There is little doubt that the damage being done by climate-change policies currently exceeds the damage being done by climate change, and will for several decades yet. Hunger, rainforest destruction, excess cold-weather deaths and reduced economic growth are all exacerbated by the rush to biomass and wind. These dwarf any possible effects of worse weather, for which there is still no actual evidence anyway: recent droughts, floods and storms are within historic variability.

The harm done by policy falls disproportionately on the poor. Climate worriers claim that at some point this will reverse and the disease will become worse than the cure. An acceleration in temperature rise, they say, is overdue. The snag is, the best science now says otherwise. Whereas the politicians, activists and businessmen who make the most noise about — and money from — this issue are sticking to their guns, key scientists are backing away from predictions of rapid warming.

Yesterday saw the publication of a paper in a prestigious journal, Nature Geoscience, from a high-profile international team led by Oxford scientists. The contributors include 14 lead authors of the forthcoming Intergovernmental Panel on Climate Change scientific report; two are lead authors of the crucial chapter 10: professors Myles Allen and Gabriele Hegerl.

So this study is about as authoritative as you can get. It uses the most robust method, of analysing the Earth’s heat budget over the past hundred years or so, to estimate a “transient climate response” — the amount of warming that, with rising emissions, the world is likely to experience by the time carbon dioxide levels have doubled since pre-industrial times.

The most likely estimate is 1.3C. Even if we reach doubled carbon dioxide in just 50 years, we can expect the world to be about two-thirds of a degree warmer than it is now, maybe a bit more if other greenhouse gases increase too. That is to say, up until my teenage children reach retirement age, they will have experienced further warming at about the same rate as I have experienced since I was at school.

At this rate, it will be the last decades of this century before global warming does net harm. As the economist Bjørn Lomborg recently summarised the economic consensus: “Economic models show that the overall impact of a moderate warming (1-2C) will be beneficial [so] global warming is a net benefit now and will likely stay so till about 2070.”

Now contrast the new result with the Met Office’s flagship climate model, the one that ministers and their advisers place most faith in. Called HadGEM2-ES, it expects a transient climate response of 2.5C, or almost double the best estimate that the Oxford team has just published. Indeed, the latter’s study concludes that it is more than 95 per cent certain that the response is below 2C, considerably short of the Met Office model’s estimate.

Why trust the new results rather than the Met Office model? The new study not only uses the most robust method, but joins several other observationally based studies from the past year that also find lower climate sensitivity than complex climate models exhibit.

Notice that this new understanding is consistent with what we have actually experienced: about 0.1C per decade over the past 50 years. The most remarkable thing about the recent milestone of 0.04 per cent carbon dioxide in the atmosphere (400 parts per million) is that it comes after 15 years of no net warming at all.

The new paper also fits the known physics of the greenhouse effect, which predicts a warming of 1.1C for a doubling of carbon dioxide. Only unverified assumptions by modellers about the added effects of water vapour and clouds have allowed politicians and activists to claim that a much higher number fits the laws of physics. Only now-disproven claims about how much the sulphur pollution in the air was masking the warming enabled them to reconcile their claims with the actual data.

It is true that the “transient climate response” is not the end of the story and that the gradual warming of the oceans means that there would be more warming in the pipeline even if we stopped increasing carbon dioxide levels after doubling them. But given the advance of nuclear and solar technology, there is now a good chance we will have decarbonised the economy before any net harm has been done.

In an insightful new book, The Age of Global Warming, Rupert Darwall makes the point that “in believing scientists and politicians can solve the problems of a far distant future, the tangible needs of the present are neglected”. The strong possibility that climate change will be slow and harmless must be taken seriously before we damage more lives, landscapes and livelihoods in its name.

For further detailed commentary on the Otto et al study, see Nic Lewis's essay here

Here we go again. A new bird-flu virus in China, the H7N9 strain, is spreading alarm. It has infected about 130 people and killed more than 30. Every time this happens, some journalists compete to foment fear, ably assisted by cautious but worried scientists, and then tell the world to keep calm. We need a new way to talk about the risk of a flu pandemic, because the overwhelming probability is that this virus will kill people, yes, but not in vast numbers.

In recent years flu has always proved vastly less perilous than feared. In 1976 more people may have died from bad reactions to swine-flu vaccine than from swine flu. Since 2005, H5N1 bird flu has killed 374 people, not the two million to 7.4 million deemed possible by the World Health Organization. In 2009, H1N1 Mexican swine flu proved to be a normal flu episode despite apocalyptic forecasts.

No doubt some readers will remind me that, in the story of the boy who cried "Wolf!", there eventually was a wolf. And that in 1918 maybe 50 million people died of influenza world-wide. So we should always worry a bit. But perhaps it's not just luck that has made every flu pandemic since then mild; it may be evolutionary logic.

The new virus is said to need just five mutations to turn it into a human-to-human pathogen, two of which have already happened. But evolution is not just about mutation; it is also about selection. Assuming that a virus acquires the capacity to spread from person to person, will its virulence rise or fall as it spreads? As Maciej Boni of Oxford University and his colleagues argue in a new paper, this is an evolutionary question, because the change will come about through the relative success of different genetic strains.

Imagine you are a flu virus. Your job is to see your progeny—copies of your genome—safely into as many new people as possible. There's competition from other mutant versions. Would you rather have your victim lying on his deathbed or out and about meeting people, albeit with a headache and a cough?

In casual-contact diseases, there is a general tendency for virulence to decline. Colds are caused by hundreds of kinds of virus, none of which has ever been seriously lethal. Mosquito-borne diseases, by contrast, benefit from making their victims so ill that they lie still in darkened rooms perspiring and attracting insects.

Why was flu so lethal in 1918? Perhaps the peculiarly crowded and intimate conditions of the trenches and field hospitals of World War I suited a high-virulence flu, though nobody can be sure. Jeffery Taubenberger of the Armed Forces Institute in Rockville, Md., and David Morens of the National Institutes of Health in Bethesda argued in a recent paper that the virus was essentially novel and that all subsequent flu pandemics consist of its low-virulence genetic descendants, sometimes with added genes from other strains. It was indeed "the mother of all pandemics."

Calculations by Dr. Boni and his colleagues show that with 60% mortality, H5N1 bird flu is still four times too lethal to be able to spread within a human population. In captive ferrets (the experimental animal of choice for flu research) it is rapidly evolving toward lower virulence. Ironically, the most worrying sign for a bird-flu pandemic would be if the virulence dropped significantly—then it could spread. There are signs this might be happening in Egypt.

There's no mystery as to why we talk up the risk every time: All the incentives point that way. Who among the headline-seeking journalists, reader-seeking editors, fund-seeking scientists, contract-seeking vaccine makers or rear-end-covering politicians has even a modest incentive to say: "It may not be as bad as all that"?

A provocative calculation by two biologists suggests that life might have arrived on Earth fully formed—at least in microbe form.

Alexei Sharov of the National Institute on Aging in Baltimore and Richard Gordon of the Gulf Specimen Marine Laboratory in Panacea, Fla., plotted the genome size of different kinds of organisms against their presumed date of origin. Armed with just five data points they concluded that genome complexity doubles every 376 million years in a sort of geological version of Moore's Law of progress in computers.

There are an awful lot of "ifs" in such a calculation. After all, the increase in complexity could have started fast and slowed down. Also, it isn't the first time somebody has suggested "panspermia," or microbial life hitching a ride here.

The molecular biologist Francis Crick wrote a whole book called "Life Itself" on one of these theories that involved intentional colonization. Crick argued that the universe was already so old when Earth was born that, if planets are common (check) and life is probable (still unknown), it was unlikely ours was the first life, in which case it was likely that advanced civilizations already existed when Earth was young and that one of them sent microbes out to seed other solar systems, knowing that the civilization itself could not manage the trip.

But then, as Enrico Fermi first asked, why have we not heard radio transmissions from these advanced civilizations? The deathly silence of the universe remains a paradox.

If it takes 10 billion years to achieve technology and civilization, Drs. Sharov and Gordon think the spore travelers were probably launched by accident from a primitive planet, rather than on purpose from an advanced one. For the same reason, they think they may have resolved the Fermi paradox, because if it takes so long to get to our stage of technology, then we may indeed be among the first to get there. And they predict that we may find life (or remains of it) on Mars, because we are unlikely to have been the only landing site for the wandering spores.

Earlier this month the National Aeronautics and Space Administration announced that its Kepler space telescope has discovered planets orbiting distant stars in the "Goldilocks" zone—neither too hot nor too cold for liquid water. Of the three planets detected, the most Earthlike is probably Kepler-62f, which is just 40% larger than Earth and orbits a star somewhat dimmer than our own sun, 1,200 light years from here.

That's too far away for direct observation, but the planet's passage across the face of its sun dims the starlight, so the size of the planet can be calculated. The ease with which Kepler is picking such planets up confirms that even small planets with rocky crusts and tepid-enough surfaces to hold oceans are probably fairly common in the universe.

Being watery creatures ourselves, depending on the free movement of soluble substances within our cells, we inevitably expect water and life to go together. It's harder to imagine evolution getting started in a gas or a solid, though perhaps this is aqua-centric. Anyway, it seems that opportunities even for water-based life may abound. Does that mean life is common? No. We still don't know if it's very easy or very hard for life to emerge from nonlife even in the right conditions.

Leave the last word to the Monty Python "Galaxy Song": "And pray that there's intelligent life somewhere up in space / 'Cause there's bugger-all down here on Earth."

Bitcoins — a form of digital private money — shot up in value from $90 to $260 each after Cypriot bank accounts were raided by the State, then plunged last week before recovering some of their value. These gyrations are symptoms of a bubble. Just as with tulip bulbs or dotcom shares, there will probably be a bursting. All markets in assets that can be hoarded and resold — as opposed to those in goods for consumption — suffer from bubbles. Money is no different; and a new currency is rather like a new tulip breed.

Yet it would be a mistake to write off Bitcoins as just another bubble. People are clearly keen on new forms of money safe from the confiscation and inflation that looks increasingly inevitable as governments try to escape their debts. Bitcoins pose a fundamental question: will some form of private money replace the kind minted and printed by governments?

It has happened before. Pennies and halfpennies were effectively privatised by industrialists in Birmingham in the 1790s. New industrial employers had to pay workers in cash rather than kind, as farmers had done. But there was a chronic shortage of small coins. The Royal Mint had given up making silver coins because people melted them down when their value as metal exceeded their face value and had stopped striking copper halfpennies, which were too easily counterfeited.

So Thomas Williams, the owner of an Anglesey copper mine, and Matthew Boulton, keen to put steam engines to work, offered to make pennies for the government. Rebuffed, Williams made coins anyway. Called druids, they were harder to fake or clip (because they had raised rims) and cheaper to strike than state coins. Being convertible into guineas and pounds at a fixed price of one penny, they were soon accepted all over Birmingham and even in London.

By 1797 there were 600 tons of such tokens in circulation and the counterfeiters were put out of business. The coiners started making silver tokens too but a jealous Royal Mint lobbied Parliament to outlaw the competition. It succeeded in 1818, three years before it could produce new copper coins to match the high standards of the private ones, so the coin famine resumed.

More recent private currencies — from Green Shield stamps and air miles to Lewes “pounds” (designed to encourage spending in the East Sussex town) — have been less ambitious than the Birmingham tokens, whose story is told in an outstanding book Good Money. Its author, the economist George Selgin, has now turned his attention to Bitcoins, which he thinks come close to having the characteristics of an ideal currency.

Bitcoins are virtual money created by a piece of computer software designed to grind away inexorably producing them at a decelerating rate — it halves every four years — until almost 21 million are in circulation, by which time the rate of production will be extremely slow. About 11 million have currently been “mined”. Private software writers can improve their “mining” rate (by solving maths problems of increasing difficulty), but only at the expense of competitors; they cannot increase the supply.

Thus, Bitcoins resemble “commodity money”, like gold or cowrie shells, which rely on scarcity and indestructibility to be a good store of value. Real commodity money is vulnerable to inflation if there is suddenly a new discovery of gold — or deflation if there is suddenly a demand to use the commodity differently. In theory “fiat money”, such as we use today, avoids these problems — but governments have always removed the check on supply by printing money at whim to reduce debts.

There might be a way to cross fiat with commodity money and capture the benefits of both. Selgin calls this “synthetic commodity” money. Unlike fiat money it would have absolute scarcity; unlike commodity money it would have no non-monetary use. For example, a government could print paper money and then ostentatiously destroy the lithograph plates to show that it would never print any more.

In effect, this happened to the Swiss Iraqi dinar in the 1990s. Saddam’s regime used high-quality money engraved in Switzerland and printed in Britain. But during the first Gulf war in 1990 the supply dried up because of sanctions. Saddam began to print dinars at home, but these were easily faked, so they fell in value. The Swiss dinars remained in circulation for many years (though growing tatty) and held their value against the dollar.

Metaphorically, Bitcoin’s creators have destroyed the plates by making it impossible for anybody to change the programmed supply. So far that part of the experiment is succeeding, but Bitcoins are not yet ready for prime time. A friend who acquired some is sitting on a handsome profit, but finds the only thing he can exchange them for in his nearest city is chocolate.

Selgin points out that to get an exchange network going from scratch is hard enough when a new currency is fully compatible with established money, as in Birmingham; or when it consists of a commodity with other uses. But to do so using something with no non-monetary uses, so no one ought to want it at all except as a means of trade, should be almost impossible.

This only makes Bitcoin’s modest foothold even more impressive. An appetite for new kinds of money is there. The use of mobile phone credits as a currency in Africa, pioneered by M-pesa, is another example, and has had as jealous a reaction from central banks as Birmingham’s private coins did from the Royal Mint.

Remember the lesson of the Anglesey druids: private entrepreneurs designed far better coins far more cheaply than sclerotic bureaucracies. Entrepreneurial innovation among Bitcoin’s imitators may yet solve the unsolved money problem — how to provide a ready medium of exchange that is also a trustworthy store of value.

The usually placid world of molecular biology has been riven with two fierce disputes recently. Although apparently separate, the two conflagrations are converging.

The first row concerns the phrase "junk DNA." Coined in 1972 by the geneticist Susumu Ohno, it is an attempt to explain why vast stretches of animal genomes, far more in some species than in others, seem to serve no purpose. Genes of all kinds and their control sequences make up maybe 9% of the human genome at the very most. The rest may be nonfunctional "junk," mainly there because it is good at getting itself duplicated. Yet the phrase has always caused a surprising amount of offense. Reports of the discrediting of junk-DNA theory have been frequent.

Why does it matter? Partly because scientists want to know if they are right to focus on part of the genome, ignoring the rest, but mainly because the issue tests an evolutionary theory about how DNA sequences can proliferate even if they do not benefit the body.

Late last year, a huge team of scientists running a consortium called Encode published an analysis of the human genome that they said showed some kind of activity in 80% of the genome. They later conceded that perhaps 20% is actually functional, yet insisted the phrase "junk DNA" could now be "totally expunged from the lexicon."

According to Dan Graur of the University of Houston and his colleagues, even this is a wild overestimate—not least because it uses a "causal role" definition of function that is all wrong, as if you were to describe among the heart's functions adding 10.5 ounces to the weight of the body, along with pumping blood. After a few exchanges, the Encode team leader Ewan Birney conceded that in hindsight, the team overstated its conclusions. But he added that whatever the interpretation, the Encode data are sound.

Are they? Here's where the junk-DNA row meets the other conflagration in molecular biology. All the Encode data were derived from cancer-cell lines. To describe human cancer cells as having the human genome looks increasingly unwise. Most cancer cells have extra chromosomes, fragmented and rearranged DNA and unusual patterns of gene activity.

As if to illustrate the point, last month a consortium of scientists based in Heidelberg, Germany, analyzed and sequenced the genome of one type of HeLa cell, an immortal laboratory cell line widely used since 1952. They described a genome that looks like a bomb has gone off in it. There are three copies of most chromosomes, yet only one copy of many genes. Hefty chunks have been reshuffled to other chromosomes, and some chromosomes have suffered from "chromothripsis," which one of the scientists describes as being "blown apart and stuck back together in a random order." A person with this genome could never be born.

Yet—and here's the source of the controversy—the HeLa cell line was derived from the tumor that killed a poor, black tobacco farmer named Henrietta Lacks in Baltimore in 1951. As Rebecca Skloot has documented in a remarkable best seller ("The Immortal Life of Henrietta Lacks"), the medical community never got her consent and treated her family with tactless disrespect for years—until Ms. Skloot's book began to make a difference.

Not enough of a difference, apparently. The German team did not seek the consent of the Lacks family before publishing the HeLa sequence, claiming it revealed nothing specific about Ms. Lacks's own genome. "Your claim is so wrong that I don't know where to start," replied one geneticist. The sequence has since been unpublished.

So here's the paradox: A cancer genome like HeLa may not be sufficiently representative of human genomes to resolve the junk DNA question, but may still give away private information about the human being from whom it derived.

We’ve discovered that we own an island. But dreams of independence and tax-havenry evaporate when we try to picnic there on Easter Sunday: we watch it submerge slowly beneath the incoming tide. It’s a barnacle-encrusted rock, about the size of a tennis court, just off the beach at Cambois, north of Blyth, which for some reason ended up belonging to my ancestor rather than the Crown. Now there’s a plan for a subsidy-fired biomass power station nearby that will burn wood (and money) while pretending to save the planet. The outlet pipes will go under our rock and we are due modest compensation. As usual, it’s us landowners who benefit from renewable energy while working people bear the cost: up the coast are the chimneys of the country’s largest aluminium smelter — killed, along with hundreds of jobs, by the government’s unilateral carbon-floor price in force from this week.

There were dead puffins on the beach, as there have been all along the east coast. This cold spring has hit them hard. Some puffin colonies have been doing badly in recent years, after booming in the 1990s, but contrary to the predictions of global warming, it’s not the more southerly colonies that have suffered most. The same is true of guillemots, kittiwakes and sandwich terns: northern colonies are declining.

It’s not just here that the cold has been relentless. Germany’s average temperature for March was below zero. Norwegian farmers cannot plant vegetables because the ground’s frozen three feet down. In America snow fell as far south as Oklahoma last week. It’s horrible for farmers. But in past centuries, bad weather like that of the past 12 months would kill. In the 1690s, two million French people starved because of bad harvests. I’ve never understood why people argue that globalisation makes for a more fragile system: the opposite is the case. Harvest failures can be regional, but never global, so world trade ensures that we have the insurance policy of access to somebody else’s bumper harvest.

Gloriously, the poor old Met Office got it wrong yet again. In December it said: ‘For February and March… above-average UK-mean temperatures become more likely.’ This time last year it said the forecast ‘slightly favours drier-than-average conditions for April-May-June, and slightly favours April being the driest of the three months’ before the wettest of all Aprils. The Met Office does a great job of short-term forecasting, but the people who do that job must be fed up with the reputational damage from a computer that’s been taught to believe in rapid global warming. In September 2008 it foretold a ‘milder than average’ winter, before the coldest winter in a decade. The next year it said ‘the trend to milder and wetter winters is expected to continue’ before the coldest winter for 30 years. The next year it saw a ‘60 per cent to 80 per cent chance of warmer-than-average temperatures this winter’ before the coldest December since records began.

At least somebody’s happy about the cold. Gary Lydiate runs one of Northumberland’s export success stories, Kilfrost, which manufactures 60 per cent of Europe’s and a big chunk of the world’s aircraft de-icing fluid, so he puts his money where his mouth is, deciding how much fluid to send to various airports each winter. Back in January, when I bumped into him in a restaurant, he was beaming: ‘Joe says this cold weather’s going to last three months,’ he said. Joe is Joe Bastardi, a private weather forecaster, who does not let global warming cloud his judgment. Based on jetstreams, el Niños and ocean oscillations, Bastardi said the winter of 2011–12 would be cold only in eastern Europe, which it was, but the winter of 2012–13 would be cold in western Europe too, which it was. He’s now predicting ‘warming by mid month’ of April for the UK.

David Rose of the Mail on Sunday was vilified for saying that there’s been no global warming for about 16 years, but even the head of the Intergovernmental Panel on Climate Change now admits he’s right. Rose is also excoriated for drawing attention to papers which find that climate sensitivity to carbon dioxide is much lower than thought — as was I when I made the same point in the Wall Street Journal. Yet even the Economist has now conceded this. Tip your hat to Patrick Michaels, then of the University of Virginia, who together with three colleagues published a carefully argued estimate of climate sensitivity in 2002. For having the temerity to say they thought ‘21st-century warming will be modest’, Michaels was ostracised. A campaign began behind the scenes to fire the editor of the journal that published the paper, Chris de Freitas. Yet Michaels’s central estimate of climate sensitivity agrees well with recent studies. Scientists can behave remarkably like priests at times.

A new study by Dirk Helbing at ETH Zurich in Switzerland and colleagues has modeled the emergence of “nice” behavior in idealized human beings. It’s done by computer, using the famous “prisoner’s dilemma” game, in which a prisoner has to decide between cooperating with a comrade to get a mutual reward or avoiding a punishment by being the first of the two to defect to the other side. The Zurich team found that so long as players in the game stay near their (modeled) parents, the birth of a nice guy predisposed to cooperate can trigger “a cascade” of generous acts.

In other words, more togetherness and physical proximity across the generations allows the development of more pro-social behavior. “The clustering of friendly agents, which promotes other-regarding preferences, is not supported when offspring move away.” They also argue that networking via social media can promote niceness, which might surprise regular users of Twitter.

This is not the first work to find mathematical evidence that there are conditions under which cooperative behavior drives out selfish behavior. The key insight of the Zurich team is that both nice “homo socialis” and nasty “homo economicus” (the selfish boogeyman who supposedly reigns in classical economics) can be promoted by evolution under particular circumstances. So long as there is little geographic mobility, clusters of networked kin and friends develop, putting an advantage on being nice.

Most evolutionists now accept that kindness might be just as ancient and innate as selfishness. But it’s also clearly conditional: People tend to cooperate with relatives and frequently encountered acquaintances, not indiscriminately.

But does commerce promote or hinder cooperative behavior? Most people assume it hinders, but economists have been arguing since before Adam Smith that markets promote good behavior as people discover the mutual advantage in exchange. “Sweet commerce,” Montesquieu called it. A virtuous circle of voluntary cooperation allows both the producers and consumers of, say, bread or electricity to be better off.

As Joe Henrich of the University of British Columbia and colleagues found in a study a few years ago, the more people in small-scale societies are exposed to modern commerce, the more generous they prove to be when faced with a test called the “ultimatum game,”­ in which participants must offer to share part of a windfall but lose it all if the recipient rejects the offer.

So the notion of “Homo economicus,” schooled by capitalism to be shortsightedly selfish, is these days something of a straw man (“Homo stramineus”?). It is found more often being beaten up in the literature of social science than being celebrated in economics.

It is futile to ask whether people are naturally cooperative or selfish. They can be either, depending on the circumstances. Dr. Helbing cites “tragedies of the commons” where open access to a common-pool resource such as a fishery tends to result in overfishing that harms everybody—a sort of extended real-world version of the prisoner’s dilemma.

Yet various economists, including the late Nobel Prize winner Elinor Ostrom, have shown that in some cases communities can and do come together to solve such tragedies, often finding a middle way between nationalizing and privatizing the threatened resource.

Likewise, the bubbles and crashes that have afflicted asset markets ever since Holland’s tulipmania in the 17th century and right up to the subprime housing bubble are also cousins of the prisoner’s dilemma. If people would only cooperate not to bid asset prices above their fundamental values, then there would not be winners and losers when prices spike and crash.

As the Nobel-winning economist Vernon Smith (now of Chapman University) and colleagues found in laboratory experiments, markets in goods for consumption promote cooperation, but markets in assets for speculation and resale produce bubbles and crashes. Once again, the difference lies in the conditions, not in the people themselves.

The east wind could cut tungsten; the daffodils are weeks behind; the first chiffchaffs are late. It’s a cold spring and the two things everybody seems to agree upon are that there’s something weird about the weather, and it’s our fault. Both are almost certainly wrong.

On weird weather, it is true that the contrast with last year’s warm March is striking, as is the difference between the incessant rain of the last twelve months and the long drought that preceded it in most of England. In the last year, America’s had a heatwave, a superstorm and now a bitterly cold spring. Australia has just had an “angry summer”. And so on.

The government’s retiring chief scientist, Sir John Beddington, claimed this week that “we are seeing more variability”. Is he right? On the whole, no. Forget the anecdotes and examine the data.

Start with America. Professor Roger Pielke of the University of Colorado has documented that floods, hurricanes, tornadoes and east-coast winter storms have shown no increase since the 1950s, while droughts have shown a slight decrease. The only thing that has changed is the financial damage done by storms, but as he drily remarks “The actual reason for the increasing number of damaging tropical storms has to do with the reporting of damages.”

What about elsewhere in the world? There has been no trend in tropical cyclone intensity or frequency worldwide at all. The Intergovernmental Panel on Climate Change itself, though heavily infiltrated by environmentalists in recent years, stated in a recent special report on climate extremes that over the coming two to three decades “signals are relatively small compared to natural climate variability” (as Matthew Parris pointed out last week, don’t you hate this habit of making forecasts in the present tense?), and that “even the sign of projected changes in some climate extremes over this time frame is [sic] uncertain”. Translated: the weather is just as likely to become less extreme as more extreme.

So why is everybody convinced otherwise? Partly because they have been listening too much to the big insurance companies, which have a vested interest in bidding up our anxiety, as Dr Pielke’s remark reminds us. Also it seems even government chief scientists suffer from what psychologists call “availability heuristic” – when people judge the probability of events from how easy it is to think of examples. Here’s an instance: “I cannot recall such a cold March”, says a man with dim memories of 1963 as he reads a Met Office report that March 2013 is the coldest in Britain since…1963. Do you remember March 1963? I don’t.

So next time some pub bore tells you this cold month is caused by the extensive melting of Arctic sea ice last summer, ask him if the same thing happened in 1983. In any case, even if there were evidence for changing weather, blaming every weather event on climate change is lazy at best and dishonest at worst. As I wrote in these pages during the cold December of 2010, “It's not climate change. It's weather: just a cold snap.”

Not that politicians took my advice. Mayor Michael Bloomberg of New York and Governor Chris Christie of New Jersey were quick to blame “superstorm” Sandy on climate change not least because it was a convenient way to deflect blame for the disastrous power and fuel shortages that afflicted communities for so long after the storm.

There was perhaps an echo of this last month when Lord Smith, chairman of the Environment Agency, incautiously blamed recent flooding on “increasing instances” of “convective rain, which sits in one place and just dumps itself in a deluge over a long period of time.” Not only did this sound to annoyed flood victims and their MPs as an excuse; it drew a sharp rebuke from the veteran weather forecaster Bill Giles, who said “There is nothing new about convective rain. Perhaps next time he should get a meteorologist to check his answers.”

As we have just experienced in a year, the variability of weather matters far more than the trend in climate. Noise matters more than signal. The world grew about half a degree warmer in the last third of the twentieth century, but the difference between March 2012 and March 2013 was almost ten times as great as that (7.7C vs 3.1C).

Suppose we get another half a degree of warming in the next three decades – and we may well do, even though there’s been no net global warming now for 16 years and the latest peer-reviewed studies (from James Annan of the Japan Agency for Marine Earth Science and Technology, Magne Aldrin of the Norwegian Computing Center and Michael Schlesinger of the University of Illinois among others) all confirm that the climate is less sensitive to carbon dioxide than the IPCC has been saying. That warming would be one-tenth as much change over 30 years as we just experienced between two versions of March in consecutive years. It would be equivalent to moving house to a new village 250 feet lower down a hill (temperature changes by 0.65C per 100 metres of altitude), or a couple of counties to the south.

It would also be about one-quarter as much warming as you would experience if you moved from rural Surrey to central London. Nearly all the stories of recent years about how much earlier flowers have been blooming came from within the massive urban heat island that is London: Kew for example has experienced more local warming than it has global warming. There is much less evidence of changing seasons from rural Britain. My diary records of the date I first heard first chiffchaff sing since 1986 show lots of variation, but no trend at all.

In the heyday of climate-change mania of a few years ago we were all told to plant cacti and drought resistant lawn grass. Yet we’ve just had a run of three out of four hard winters and they killed off the eucalypts and Wollemi pines my father planted in his arboretum. It’s a racing certainty that you will still have to plan for occasional hard winters and you won’t have to tell your children what snow is.

The lesson that weather matters more than climate is not just a bit of fun. Airports and our councils forgot to plan for snow a few years ago, because they were more focused on the trend than the variability. In 2010 Brisbane disastrously overfilled a dam because it expected drought to return; the dam could not absorb a flood when it came.

Climate is what you expect; weather is what you get. Which is presumably what the first chiffchaffs will be soon be saying to themselves as they desperately search the barren tree branches for frozen insects.

I have published the following article in the Newcastle Journal (paywalled) today:

Three hundred years ago this year, in 1713, some of the very first Newcomen steam engines in the world were being built in the North-east to pump water out of mines. One was at Oxclose near Washington, another a Norwood near Ravensworth and a third at Byker.

The Byker one had been commissioned -- probably without a licence from the patent holder in London -- by my ancestor Richard Ridley. It cost a huge sum but proved a great success, clearing the water from a flooded pit that had ruined more than one previous owner. Within a few years, much improved by the engineer Henry Beighton (who doubled the operating speed to 16 cycles a minute), these great clanking monsters were going up all over the North-east.

Their effect was dramatic. Pits became more productive so cheap energy became a fact of life in the region; metal-workers had a new market building cylinders and beams for steam engines; machinery inventors had new customers lured into automation by cheap fuel; jobs were created outside agriculture, in glass making, salt production, brewing and other trades. And the great flywheel of the industrial revolution began to whir.

Within a few decades, Newcastle probably had the highest average income of any city in the world, and a very high ratio of labour costs to energy costs. For the first time the economy began to grow not through an increase in land or labour, but through an increase in energy and productivity.

An extraordinary surge in human living standards came about as a result of those engines and continues to this day. The world economy is expanding at about 3-5% a year even now, largely thanks to the harnessing of cheap energy in place of cheap labour in farming, manufacturing and services.

Yet here in Britain we face stagnation. One of the reasons we as a country are not sharing in this growth today, in my view, is because we have a policy of pursuing expensive energy: subsidizing costly and unreliable wind and biomass power, while closing down coal and delaying gas. We’re in danger of losing much of our chemical industry industry to North America because of their cheap shale gas, now one third of the price of gas in this country. Even computer-server firms are looking to move to the USA, where electricity is cheaper.

Maybe I am biased, as somebody who still makes money from coal as my ancestors did. But I have no vested interest in the really exciting energy opportunity that’s within the North-east’s reach: offshore coal gasification. For we could do it again. We could steal a march on the world in the field of energy.

There’s 3,000 billion tonnes of coal under the British sector of the north sea, says Harry Bradbury of Five Quarter, a Newcastle University spin out. He argues that it’s soon going to be possible to turn the offshore oil industry into a coal gasification industry instead, getting methane, hydrogen and carbon monoxide out of that subsea coal and putting carbon dioxide back in. In other words, a hugely abundant, potentially cheap, low-carbon source of energy on our doorstep.

For the North-east this is exciting news. It’s an example of what Lord Heseltine said recently – there’s an enormous amount of entrepreneurial energy in the regions waiting to be unleashed if Whitehall would just stop telling us what not to do.

So don’t let’s underestimate the importance of what our predecessors on Tyneside achieved for the entire world. It’s the fashion these days to vilify coal as the root of all environmental evil, but I think that’s mistaken. Coal and the technologies it spawned made it possible to double human lifespan, end famine, provide electric light and spare forests for nature. Because we get coal out of the ground, we do not have to cut down forests; because we use petroleum we don’t have to kill whales for their oil; because we use gas to make fertilizer we don’t have to cultivate so much land to feed the world.

This country can compete with China on the basis of either cheap labour or cheap energy. I know which I’d prefer.

Obsidian was once one of humankind's most sought-after materials, the "rich man's flint" of the stone-age world. This black volcanic glass fragments into lethally sharp, tough blades that, even after the invention of bronze, made it literally a cutting-edge technology.

Because sources of obsidian are few and far between, obsidian artifacts are considered some of the earliest evidence of commerce: Long-distance movement of obsidian, even hundreds of thousands of years ago, suggests the early stirring of true trade.

Differences in the trace elements in each volcanic source let archeologists trace the origin of individual obsidian artifacts and reconstruct trade routes. A new study, by Ellery Frahm of the University of Sheffield and Joshua Feinberg of the University of Minnesota, has used such obsidian tracing to shed light on how trade collapsed in the Akkadian empire of the early Bronze Age around 4,200 years ago in what is now northern Syria.

In the 23rd century B.C., a usurper named Sargon became king of Akkad and conquered all of Mesopotamia, but his empire collapsed soon after his death. At a site called Tell Mozan, which seems to have been "Urkesh"—the capital of the Hurrians, a people whom Sargon conquered—Drs. Frahm and Feinberg uncovered 97 obsidian artifacts from a palace and temple complex. The objects date from before and after 2200 B.C., which is when the Akkadian empire apparently disintegrated, as evidenced by the abandonment of cities and a change in the variety and standard of pottery.

Three of the 97 obsidian objects came from sites much farther west, places whose obsidian normally ended up being used around the Mediterranean. This probably implies occasional VIPs passing through, rather than regular trade. The remaining objects originated from sites in Eastern Anatolia.

However, there was a dramatic change in the obsidian objects at Urkesh around the time of the collapse. Before, the objects came from six different sources in Anatolia, implying that Urkesh was a cosmopolitan city visited by traders from different places. Afterward, the objects came from just two of the nearer sites.

Moreover, using a new magnetic technique, Drs. Frahm and Feinberg can identify which quarries at the two sites were used, and they find that, after the collapse, different quarries were being used from before. The obsidian thus confirms the suggestion from pottery evidence that there was some sudden disruption at this time and that trade atrophied.

Why? For many years the Akkadian collapse has been explained according to the academic fashion of the time. The first culprit was thought to be unsustainable agricultural practices, leading to the exhaustion of the soil and the displacement of farmers by shepherds. More recently, climate change has been blamed. A megadrought supposedly resulted from global cooling, caused by either a large volcanic eruption or a big meteorite strike elsewhere on the planet. But the evidence for a global climate event around this time is shaky.

A regional rainfall failure does seem to have happened, as evidenced near Tell Mozan by changes in crops, river flow and the disappearance of forests. Yet Karl Butzer of the University of Texas at Austin argues in a new paper that pollen records and an increase in contemporary canal building further downstream in the lower Euphrates valley (implying an increase in available water) mean "it is implausible that the Akkadian heartland collapsed because of a megadrought."

Instead, Dr. Butzer argues that Sargon's conquest itself caused the collapse of trade by destroying cities and disrupting what had till then been "an inter-networked world-economy, once extending from the Aegean to the Indus Valley." In other words, as with the end of the Roman empire, the collapse of trade caused the collapse of civilization more than the other way around.

Move over shale gas, here comes methane hydrate. (Perhaps.) On Tuesday the Japanese government’s drilling ship Chikyu started flaring off gas from a hole drilled into a solid deposit of methane and ice, 300 metres beneath the seabed under 1000 metres of water, 30 miles off the Japanese coast.

The real significance of this gas flare probably lies decades in the future, though the Japanese are talking about commercial production by 2018. The technology for getting fuel out of hydrated methane, also known as clathrate, is in its infancy. After many attempts to turn this “fire ice” into gas by heating it proved uneconomic, the technology used this week – depressurizing the stuff – was first tested five years ago in Northern Canada. It looks much more promising.

Methane hydrate is found all around the world beneath the seabed near continental margins as well as in the Arctic under land. Any combination of low temperature and high pressure causes methane and water to crystallise together in a sort of molecular lattice. Nobody knows exactly how much there is, but probably more than all the coal and oil put together, let alone other gas.

The proof that hydrate can be extracted should finally bury the stubborn myth that the world will run out of fossil fuels in any meaningful sense in the next few centuries, let alone decades. In 1866, William Stanley Jevons persuaded Gladstone that coal would soon run out. In 1922 a United States Presidential Commission said “Already the output of gas has begun to wane. Production of oil cannot long maintain its present rate.” In 1956, M. King Hubbert of Shell forecast that American gas production would peak in 1970. In 1977 Jimmy Carter said oil production would start to decline in “six or eight years”. Woops.

The key will be cost. However, Japan currently pays more than five times as much for natural gas as America so even high-cost gas will be welcome there. The American economy, drunk on cheap shale gas, will not rush to develop hydrate. (Unlike oil, there is no world price of gas because of the expense of liquefying it for transport by ship.)

(chart from here: http://images.rcp.realclearpolitics.com/172408_5_.jpg)

The shale gas revolution is effectively already putting a ceiling on the price of energy. America has lost its appetite for gas imports, which now go to Europe and Asia instead, but is gaining an appetite for exporting gas. Domestically, America’s cheap gas has caused electricity generators to switch from coal to gas, and buses and trucks to start switching from oil to gas. Even if hydrate proves stubbornly expensive – and it’s generally wise not to bet against Japanese ingenuity – it will put a roof over this price ceiling.

Hydrate and shale are not the only new sources of gas. Thanks to newly perfected drilling technology, new deep-sea gas fields are coming online off Brazil, Africa, and in the eastern Mediterranean. The days when gas production was concentrated in a few charming places like Iran, Russia, Venezuela and Qatar are gone.

Indeed, one of the best ways to love the new gas-fired future is to list the people who detest it. As recounted in a new documentary film called “FrackNation”, Vladimir Putin, at a dinner with journalists in 2011, suddenly became agitated about the supposed devastation of Pennsylvania by shale gas industry. His new-found concern for the Appalachian countryside might just have something to do with the threat that shale gas poses to Gazprom’s stranglehold on European markets.

For those still concerned about climate change, this is also good news. In atomic terms, methane is one-fifth carbon and four-fifths hydrogen. Not even the most die-hard environmentalist can find anything bad to say about burnt hydrogen, or “water”. Given that combined-cycle gas turbines run at higher energy-conversion efficiency than coal-fired steam turbines, the carbon dioxide output from gas-fired electricity is well below half that of coal-fired.

Thanks to shale gas, America’s carbon dioxide emissions in energy production have plummeted by nearly 20% in five years without political targets or policies, while Europe’s have hardly changed despite expensive schemes to subsidise the producers of renewable energy and penalize fossil fuels. (Apart from hydro, which has little capacity for expansion, and biomass, which is environmentally worse than fossil fuels, renewable energy remains an irrelevance in the energy debate. Even now, Britain still gets less than one percent of its total energy from wind.)

Moreover, there is a possibility that methane hydrate could be almost carbon neutral. The University of Bergen in Norway has developed a process that pumps carbon dioxide into the hydrate deposits, where it replaces the methane, turning methane hydrate into carbon dioxide hydrate. The results from a field trial in Alaska are expected any day. If this process can be scaled up, and if the carbon dioxide from burning the methane could be captured economically (big ifs), in future Japan could run on fossil fuels but generate almost no carbon emissions.

As it takes market share from oil and coal, gas will dominate the world’s energy supply for much of this century, before perhaps giving way to something cheaper. That could be cheaper and safer forms of nuclear energy based probably on thorium rather than uranium, or maybe solar power.

Not only has cheap gas given the United States falling carbon dioxide emissions, it has also delivered it a huge competitive advantage in manufacturing. Firms are “re-shoring” their operations from Europe and even China, as the low cost of American gas outbids the low cost of Chinese labour. To be competitive, countries must have either cheap labour or cheap energy. The European elite’s strange determination to have neither is the root cause of its current stagnation.

Update: Predictably one reader did indeed object to the statement that "not even the most die-hard environmentalist can find anything bad to say about burnt water". Here's my reply:

You say in response to my Times article that the production of H2O through the burning of fossil fuels is "actually worth worrying about". It made me get out my calculator! I'm not much of a physicist or mathematician, so feel free to check my working.

We produce about 26 billion tonnes of CO2 a year by burning fossil fuels.

CO2 molecular weight is about 6 times that of water.

So, assuming our average fossil fuel atomic ratio is about CH2 (i.e., half way between gas and coal),

Then we produce about 9 billion tonnes of water vapour each year by burning fossil fuels.

Total worldwide evaporation and precipitation of H2O is 550,000km3/yr.

1 km3 = 1.57 billion tonnes.

So 863,000 billion tonnes of water falls from the sky each year.

9/863,000 = c 1/100,000

So fossil fuel burning adds 0.001% to the natural water cycle. 99.999% of rainfall is natural.

Of course, local effects could be larger, but are just as likely to be beneficial as bad, and that would make the general effect smaller still.

"Worth worrying about"? Surely not compared with other environmental issues?

2nd update: I made two mistakes above, according to those with better physics knowledge than me. The molecular weight of CO2 is 2.5 times that of water; and  1 km3 of water weighs 1 billion tonnes (of course). So the true result is that fossil fuel burning is adding 0.002% to natural precipitation, not 0.001%. Still well short of "worth worrying about".

Extinct species are gone forever. Or are they? For some time now the dream of re-creating something like a mammoth from its DNA has been floating about on the fringes of the scientific world (and in movies like "Jurassic Park") without being taken seriously.

Now, however, the science is getting serious. A new organization, Revive and Restore, under the auspices of the Long Now Foundation (a hip think tank), with the help of National Geographic and TED (a hip conference organizer), is setting out its stall at TEDxDeExtinction, a meeting in Washington, D.C., on March 15.

The founders of Revive and Restore aren't mainstream scientists, but they're not people to be taken lightly, either. Stewart Brand and Ryan Phelan are a husband-and-wife team with a track record of starting unusual but successful organizations—in his case, the Whole Earth Catalog and the Global Business Network; in hers, the consumer-focused startups Direct Medical Knowledge and DNA Direct. They've attracted the interest of the pioneering Harvard University DNA sequencing and synthesis expert George Church.

Their argument is that it's time to start tentatively trying de-extinction and thinking through its ethical and ecological implications. There are already projects under way to revive extinct subspecies like the European aurochs (a type of wild cattle) and the Pyrenean ibex, or bucardo. In the latter case, when the last female (Celia) was killed by a falling tree in 2000, her tissue was cloned. At least one fetus survived to term in a surrogate mother goat, but it died soon after birth.

A full species that's been extinct for decades like the thylacine (Tasmanian tiger) or the passenger pigeon—the last one of which, Martha, died in the Cincinnati Zoo 99 years ago—will be a taller order, since the DNA from long dead specimens is fragmented. Yet Ben Novak, a young researcher working with the ancient-DNA expert Beth Shapiro at the University of California, Santa Cruz, has extracted passenger pigeon DNA from the toe pad of a museum specimen and sequenced it. Dr. Church hopes to use one of the newly invented letter-by-letter gene-replacement techniques, such as Talens or Crispr, to transform the genome of a related species called the band-tailed pigeon into that of a passenger pigeon.

There's little doubt that this will succeed. Until recently the next step looked harder—to persuade another species to lay a passenger pigeon egg. But now Michael McGrew of the Roslin Institute in Scotland and colleagues at Dubai's Central Veterinary Research Laboratory have extracted chicken germ cells and put them into ducks so that the duck produced chicken sperm. The "chimeric" duck then mated with a chicken and produced normal chicken chicks. So a pair of chimeric ducks or chickens could in theory produce passenger pigeon chicks.

Of course, that's where the ecological and ethical fun starts. Some ecologists are opposed to the whole idea, fearing that it will make people less concerned about species extinction. Mr. Brand counters that the project should redouble the urgency of preserving habitats for extinct species to reoccupy. Others worry that the passenger pigeons won't have parents to teach them where to migrate. But the restorers of endangered species like whooping cranes and California condors have surmounted such hurdles. Hand-reared cranes are taught to migrate following microlight aircraft.

Ms. Phelan emphazises that there's plenty of time to get it right. It will take years to re-create the birds perfectly and more years to build their population through captive breeding. Further time will be needed to ensure that their old habitat (and the inevitable regulators) will welcome them. Perhaps the passenger pigeon might turn into a pest. It was once probably the most numerous bird in the world, with flocks that darkened the skies for hours. What a nice problem that would be to have again.

Last week, just as a meteorite exploded over Russia, I used this space for an email to Charles Darwin, wherever he is. I told him about the now overwhelming evidence for an asteroid impact having caused the extinction of dinosaurs. I thought he would be interested because it is a striking exception to his "uniformitarian" assumption that, in the past, evolution was shaped by the same forces still operating on Earth today.

His ghost emailed back to say that he wanted to know what happened after the impact. He always had a long-standing interest in colonization—how animals and plants find and fill vacant lots in nature. So here's my reply:

To crdarwin@evolution.hvn

Dear Dr. D (sorry for my informality last week),

When the asteroid slammed into the Yucatán Peninsula 66,038,000 years ago, North America took the brunt of the impact, because the asteroid came in from the southeast like a golf chip shot. Most of what is now the American Midwest was then under shallow water called the Bearpaw Sea, but the land on either side was devastated. The shock wave destroyed almost every living thing for hundreds of miles, then a "divot" of dust and mud buried the continent, quickly followed by tsunamis that penetrated far to the north.

The Earth's southern continents suffered far fewer extinctions, though there was still a marked drop in the abundance and diversity of animals and plants. Nonetheless, the effects of the collision were felt globally. All around the world, the dinosaurs died out—too big and specialized to cope, even if they survived the blast. With them went the last of the flying pterosaurs, many kinds of birds and mammals, lots of plants and a huge range of sea creatures.

The animals that suffered the fewest extinctions were ones like alligators, turtles and salamanders. Perhaps protected by the water, while feasting on the dead or on water plants that did not suffer so much, they were also used to withstanding long fasts.

When the dust settled, as the paleontologist Tim Flannery recounted in a fine book "The Eternal Frontier," North America was virtually devoid of flora and fauna, except in the far North and in pockets to the west of the Sierra Nevada mountains. It must have been a great brown, dusty and muddy waste. Pollen evidence shows that ferns were the first plants to bounce back, just as they were after the eruptions of Krakatau and Mount St. Helens. The pollen and spore record shows a sharp "fern spike." Soon ferns must have dominated the landscape so much that they formed endless, impenetrable thickets.

When trees did recolonize, they did so from the far north (the North Pole was under land and ice-free at this time), meaning that deciduous types of trees came to dominate even warm parts of the North American continent. Mammals reappeared within 20,000 years, probably from Asia via an Arctic land bridge. South America was off doing its own thing, farther south than it is now, and could not supply animals, apart from birds, to its northern neighbor.

All this we now know. The amazing thing about this story, Charles, is that not a jot of it was known even when I was a boy, let alone you. There is something almost miraculously exciting about the way we can recover and relive the past adventures of the planet in glorious detail thanks to modern science.

You once wrote, in a letter to your sister from the Falkland Islands in 1834, of the pleasure of "finding a fine group of fossil bones, which tell their story of former times with almost a living tongue." Today, almost 180 years later, the fossils, isotopes and spores not only speak softly of slow and gradual changes but cry out the story of a violent and truly terrible catastrophe that once transformed life on Earth.

The future has a richer past than the past did. By this I mean that one of the great benefits of modern science is that it enriches our knowledge of the past. Imagine how thrilled Charles Darwin would have been to learn this week that it's now all but certain that the extinction of the dinosaurs was caused by an asteroid (much bigger than the one that missed us this week) slamming into Mexico about 66,038,000 years ago. In fact, I might send him an email to explain.

To: crdarwin@evolution.hvn

Hi, Charlie (if I may),

You know how you championed the cause of "uniformitarianism" in geology? For instance, that fossils of sea creatures on mountain tops weren't put there by big catastrophes, like Noah's flood, but by unimaginably slow and gradual changes of the same kind we see today acting over immensely long periods. Well, you were mostly right, but there's now an important exception.

Don't worry, it doesn't involve Noah. In 1980, father-and-son scientists, Louis and Walter Alvarez, found a thin layer of enriched iridium in rocks from the end of the Cretaceous period, when the dinosaurs died out. Iridium is rare on Earth, more common in space. Maybe, they said, a comet or an asteroid hit the earth, and the ensuing dark, cold, acidic conditions killed off the dinosaurs and a lot of other creatures.

Many geologists and zoologists resisted the idea, if only because it seemed a return to the special pleading of catastrophism that your friend the geologist Charles Lyell had first challenged. But in 1990, based on the work of a geologist named Glen Penfield, a crater was identified—a 110-mile-wide circle dating to the same period as the extinction event and buried deep beneath limestone centered on Chicxulub, on the northern shore of the Yucatán Peninsula.

Other evidence accumulated—shocked quartz grains, spherules of molten rock, charcoal from forest fires, tsunami beds, even a few fragments of the object itself, a carbonaceous chondrite asteroid. The layer of clay that separates the age of the dinosaurs from the one that followed bears witness to a lot of sediment in the air and water. A rock, 6 to 9 miles across, had slammed into the shallow sea, instantaneously opening a 2-mile-deep crater in the Earth's crust with the force of a billion Hiroshimas (which I'll explain later).

By the turn of the 21st century, even the scientists most committed to gradualism had to admit that a very big collision had happened. But many resisted the conclusion that it had wiped out the dinosaurs, chiefly because the dates seemed not to match: Several studies put the impact 180,000 years too early. Others said it came too late.

Now Paul Renne at the University of California at Berkeley and colleagues have used an argon/argon dating technique to narrow down the timing of both the extinction (in a layer of coal from Montana) and the impact (in specks of molten rock from Haiti). Using the technique, which depends on the radioactive decay of a potassium isotope into argon gas, Dr. Renne was able to establish that the two events coincided, in his words, to within "a gnat's eyebrow": to within 11,000 years of each other.

Dr. Renne and colleagues do concede that the climate had become more unstable before the crash, with a sharp cooling of eight degrees Celsius evident in North Dakota about 100,000 years earlier, perhaps because of huge volcanic eruptions. That might (or might not) have weakened the dinosaurs' resistance and made them more vulnerable, but there's now little doubt that it was the impact that finished them off.

Charlie, I have to dash now, but ping me if you want another email next week about what happened after the asteroid hit and how North America, which bore the brunt of the devastation, gradually got its plants and animals back.

It is more than a third of a century since a human disease was extinguished. The last case of smallpox was in 1977, and in those days health experts expected other diseases to follow smallpox quickly into oblivion. Polio has repeatedly disappointed campaigners by hanging on, though it now affects less than 1% as many people as at its peak in the 1950s.

The generosity of Bill Gates has done much to speed the decline of polio, and he and most experts now see its end within six years at most. India, 10 years ago the worst-affected country, has been polio-free since 2011, and only three countries still host the virus: Pakistan, Afghanistan and especially Nigeria. Though the murder of nine polio vaccinators in Pakistan by Islamists in December was a tragic setback, last year there were just 222 new polio cases world-wide.

As Mr. Gates recounted in his 2013 annual letter from the Gates Foundation, the reason for his optimism is that a new approach is bearing fruit, especially in northern Nigeria. Volunteers on foot (but guided by GPS and satellite imagery) map unrecorded villages and houses to identify gaps in vaccination programs.

The Guinea worm, a disease that the Carter Center has relentlessly pursued, will probably edge out polio to the disease extinction line. In 1986, more than 3.5 million Africans and Asians were afflicted with Guinea worm, or dracunculiasis; in 2012, just 542 caught the parasite.

The larvae of this nematode worm live inside freshwater copepods, or "water fleas." When the copepods are ingested in drinking water, the worms burrow through the stomach wall into the body cavity and mate. The females, which can reach 3 feet in length, then drill their way down the inside of the victim's legs over a year before erupting painfully from a burning blister on the foot. The victim is tempted to immerse the blister in water to cool it, which allows the worm to release its larvae to seek copepods. The only cure is to pull the worm out over many weeks, inch by inch, winding it round a stick as it emerges. There is no vaccine.

Filtering water to prevent the ingestion of water fleas and making sure infected people do not enter water are the best means of prevention. Guinea worm was first targeted for eradication before polio, and it, too, has been disappointingly stubborn. But last year the number of cases halved from the year before, meaning that there are fewer guinea worms left in the world than black rhinos. The handful of cases in Chad (10), Mali (7) and Ethiopia (4) are expected to dwindle to nothing this year, but there were 521 cases in South Sudan (mostly in just one county), where eradication might take one or two more years of hard work, urged on by Mr. Carter and backed by money from the Gates Foundation, the British government and other donors. Guinea worm would be the first animal to be deliberately driven extinct.

Supposing these two welcome eradications do happen this decade, what parasites go next? Don Hopkins of the Carter Center says lymphatic filariasis, another worm carried by mosquitoes, could be gone by 2020. Onchocerciasis, or river blindness, carried by black flies, is almost gone from the Americas but will take longer to eradicate in Africa.

The first bacterium to be driven extinct could be yaws, an infection of children related to the organism that causes syphilis, which disfigures many people, especially in Ghana, Ivory Coast, Papua New Guinea and the Solomon Islands. Easily treated now with a single dose of azithromycin, an antibiotic, yaws should be gone by 2020.

A friend who once studied courtship in dung beetles alerted me last week to a discovery. On moonless nights, African scarab beetles, which roll balls of dung, can use the Milky Way to navigate in fairly straight lines away from dung piles, thus avoiding other dung beetles keen to steal their dung balls. "Now this is real science, simple, fascinating and completely wonderful," enthused my friend.

Marie Dacke of Lund University in Sweden and her colleagues put dung beetles inside a planetarium at Wits University in South Africa with a pile of dung, and with or without little caps over their eyes. The results of the beetles' peregrinations clearly showed that being able to see the stars keeps the beetles relatively straight, even if just the Milky Way is projected overhead without other stars. This is the first demonstration of star navigation by insects and of Milky Way navigation by any animal.

As my friend implies, insect navigation is about as ivory-tower as science gets-practical uses seem far-fetched in the extreme. But as I delved further into the topic, I soon began to bump into things that might eventually be, if not of use, then perhaps of relevance to human beings. At least one of the molecular mechanisms used by insects for navigation is shared with people, hinting that we may have at least a vestigial capability to sense direction.

Far more spectacular than the short-distance scrambles of dung beetles are the migrations of monarch butterflies, which home in on one small region of Mexico for the winter then return as far north as Canada in a flight of thousands of miles that takes more than one generation. Clearly the insects have an inherited "map" of where to go, but what compass do they use?

It seems they have at least two compasses. One is a "time-compensated sun compass," located in their antennae, which calculates bearings from the angle of the sun corrected for the time of day. Steven M. Reppert of the University of Massachusetts Medical School and colleagues found that removing one antenna does not disrupt navigation, but painting one black does, because it messes up the clock mechanism in the animal's brain.

But butterflies can also use the Earth's magnetic field to navigate. The butterfly antennae contain a protein molecule called cryptochrome, which can apparently act as a magnetic compass when exposed to blue or violet light. Human beings and other mammals also have a cryptochrome in their retinas, albeit in slightly different form, but until recently it was thought not to have magnetic directional properties.

Recently Dr. Reppert and his colleagues took the human version of the gene that's the recipe for cryptochrome and genetically engineered it into flies, replacing the flies' own version. They then showed that, presented with two routes in a maze, the flies could choose a magnetic direction they had been trained to associate with a sugar reward, and they did so just as well with the "human" cryptochrome as with their own.

If it is at least possible to use our cryptochrome molecules to sense direction from the Earth's magnetic field, do we? Birds do. Night-migrating songbirds, when they cannot see the stars, use the Earth's magnetic field as a cue. From recent research, it appears that they "see" it, using cryptochrome-rich neurons in the retina of the eye.

To us that sensation, seeing a magnetic field, sounds unfamiliar to say the least, though it could be unconscious. So far the evidence that people can navigate magnetically is bedeviled by unreliable experiments and extravagant claims. Chances are that our navigational instinct was either not used for long-distance migration or has atrophied; stories of people returning to the same spot over thousands of miles are hardly common. Without a compass, travel agent or GPS, that is.

A war within anthropology over the causes of war itself seems to be reaching resolution. The great ethnographer of the gardener-hunter Yanomamo Indians of Venezuela, Napoleon Chagnon, has long been battling colleagues over whether men in prestate societies go to war over protein or women. Next month he'll publish a memoir, "Noble Savages," detailing (as the subtitle puts it) "My Life Among Two Dangerous Tribes-the Yanomamo and the Anthropologists." This is a good time to look back at how his argument has fared.

In the 1960s, cultural anthropologists led by Marvin Harris argued that conflict among prestate people was mostly over access to scarce protein. Dr. Chagnon disputed this, arguing that Yanomamo Indians' chief motive for raiding and fighting-which they did a great deal-seemed to be to abduct, recover or avenge the abduction of women. He even claimed that Indian men who had killed people ("unokais") had more wives and more children than men who had not killed, thus gaining a Darwinian advantage.

Such claims could not have been more calculated to enrage the presiding high priests of cultural anthropology, slaughtering as it did at least three sacred cows of the discipline: that uncontacted tribal people were peaceful, that Darwinism had nothing to say about human behavior and culture, and that material resources were the cause of conflict.

Sure enough, Dr. Chagnon, who is now at the University of Missouri, was subjected to an escalating series of political assaults, abetted by some indigenous peoples' champions and Catholic missionaries with whom he had also fallen out after he exposed their tendency to supply shotguns to Yanomamo Indians to lure them into settlements. He was eventually exonerated, most recently in an exhaustive study by the historian and bioethicist Alice Dreger of Northwestern University-but not before his reputation had been dragged through mud.

Meanwhile the science has been going Dr. Chagnon's way. Recent studies have confirmed that mortality from violence is very common in small-scale societies today and in the past. Almost one-third of such people die in raids and fights, and the death rate is twice as high among men as among women. This is a far higher death rate than experienced even in countries worst hit by World War II. Thomas Hobbes's "war of each against all" looks more accurate for humanity in a state of nature than Jean-Jacques Rousseau's "noble savage," though anthropologists today prefer to see a continuum between these extremes.

A Darwinian explanation of warfare would imply that similar kinds of violence might have evolved in other group-living animals. In recent years, Richard Wrangham of Harvard University has described chronic intergroup violence among chimpanzees. In a paper, he and Luke Glowacki note that both nomadic human hunter-gatherer bands and chimpanzee troops practice lethal attacks on neighboring groups. But they do so, according to the paper, "only in carefully selected contexts (local 'imbalances of power') that impose little risk of harm on the aggressors"-unlike modern warfare.

In the Andaman Islands, for example, one ethnographer's description eerily recalls the way primatologists describe chimpanzee violence: "The most elementary form of warfare is a raid (or type of raid) in which a small group of men endeavor to enter enemy territory undetected in order to ambush and kill an unsuspecting isolated individual, and to then withdraw rapidly without suffering any casualties."

But what is the motive for such killing? Robert Walker of the University of Missouri, Columbia, and Drew Bailey of Carnegie Mellon University last year published a survey of "Body Counts in Lowland South American Violence" and concluded that motives include revenge for previous killings, jealousy over women, capture of women and children and, less often, theft of material goods.

Come to think of it, sounds just like the Trojan War.

Not only is the capacity for forming large social networks in monkeys partly genetic, but some of the genes that affect this ability may now be known. So suggests a new study of an isolated population of free-living macaques on an island off Puerto Rico.

Lauren Brent of Duke University and her colleagues collected information on the social networks of about 100 monkeys, measuring how much time they spent grooming each other and how close together they sat. The researchers recorded not only how many "friends" each had but how many "friends of friends." The latter measure, in both social animals and human beings, has proved valuable in determining rank and well-being.

Because the family tree of this isolated population of monkeys is well known, Dr. Brent and her colleagues could tease apart the influences of nature and nurture. They found that, correcting for things such as sex and age, a monkey's "tendency to interact frequently in an affiliative manner with partners who themselves interact affiliatively at high rates with others" could be at least partly predicted from its genetic parentage.

Moreover, based on which version the monkeys had of the genes SLC6A4 and TPH2, the researchers were able to predict which individuals spent a lot of time grooming partners who themselves spend a lot of time grooming their own partners. The statistical significance of this finding remains tentative, but it looks as if having the rare version of both genes made monkeys less social, while either mutation alone had no effect.

The mutations making monkeys less social have been tied to anxiety and a tendency to avoid risks. This may explain why they persist. Although well-connected monkeys generally have more offspring, anxious monkeys may be more vigilant to threats.

It's a measure of the way the intellectual world has evolved that 50 years ago such a study would have shocked the scientific world and brought down a storm of protest.

When the great California Institute of Technology geneticist Seymour Benzer set out in the mid-1960s to find mutations in fruit flies that affected behavior, rather than mere anatomy, he was ridiculed for challenging the consensus that all behavior must be learned.

Benzer told the geneticist Max Delbrück about the plan to find behavioral mutants; Delbrück said it was impossible. To which Benzer replied: "But, Max, we found the gene, we've already done it!" (Benzer's mother was more succinct: "From this, you can make a living?") He was soon able to identify mutations related to hyperexcitability, learning, homosexuality and unusual circadian rhythms, like his own: Benzer was almost wholly nocturnal.

Since then, thanks to studies of human twins and a rash of genetic investigations in animals, it has become routinely accepted that most things, including personality, sexual orientation and intelligence, are to some degree affected by genes. The University of Virginia's Eric Turkheimer has declared what he calls the "first law of behavior genetics": that all human behavioral traits are heritable.

In 2009 a study of human twins by James Fowler of the University of California at San Diego and colleagues found evidence of genetic heritability of social networks similar to that now reported in monkeys. Frankly, there's nothing surprising here. We all know people who are intrinsically less sociable than others, because of their personalities not their circumstances.

As always in such nature-nurture debates, the red herring to avoid is "determinism." A discovery that genes affect behavior is no more or less deterministic than a discovery that family or education does so. Whether you are antisocial because your mother was unemotional-a fashionable theory in the 1960s-or because of a mutation tells you nothing about whether your condition can be remedied by some intervention.

Just to get your mind around this feat, imagine taking about 5,000 different novels and reprinting them in normal font size on 23 very long cotton ribbons. Since each word takes up about half an inch, the ribbons, placed end to end, would stretch for roughly three million miles-120 times around the world. But to be a bit more realistic, twist and tangle the ribbons so much that they only go around the planet once.

One of the books written on your ribbons is "A Tale of Two Cities," but you don't even know which ribbon it is on, let alone where on that ribbon. Your task is to find the clauses "It was the beast of times, it was the worst of times" and correct the misprint.

Little wonder that precision genetic engineering has taken a while to arrive. In truth, it has been moving steadily toward greater precision for 10,000 years. Early farmers in what's now Turkey introduced a mutation to wheat plants in the "Q gene" on chromosome 5A, which made the seed-head less brittle and the seed husks easier to harvest efficiently.

They did so unknowingly, of course, by selecting from among random mutations.

Fifty years ago, scientists used a nuclear reactor to fire gamma rays at barley seeds, scrambling some of their genes. The result was "Golden Promise," a high-yielding, low-sodium barley variety popular with (ironically) organic farmers and brewers. Again, the gene editing was random, the selection afterward nonrandom.

Twenty years ago, scientists inserted specific sequences for four enzymes into rice plants so that they would synthesize vitamin A and relieve a deadly vitamin deficiency-the result being "golden rice." This time the researchers knew exactly what letters they were putting in but had no idea where they would end up.

In recent years, it has become possible to insert a DNA sequence into a specific location on a chromosome using "zinc finger proteins," which recognize target sequences. But these will work only for certain sequences, and with low efficiency. More recently, a process known by the acronym Talens has proved more adaptable.

This week, Recombinetics of St. Paul, Minn., patented gene-editing technologies that employ Talens for use in livestock improvement. As a first application in agriculture, Recombinetics has used Talens to introduce into Holstein dairy cattle the key mutation (found naturally in Red Angus beef cattle) that keeps horns from growing. The plan is to avoid having to physically dehorn dairy calves, a stressful and expensive procedure.

Scott Fahrenkrug, chief executive of Recombinetics, points out that you could crossbreed Holstein and Angus to achieve the same result, but it would dilute the milk-producing traits in the Holstein. The firm aims to produce pigs and cattle that are more resistant to disease and to use the technology to correct fertility-compromising mutations in cattle that have emerged in selective-breeding programs.

The latest technique, from a team led by Feng Zhang of MIT, promises to be even cheaper than Talens, but it is still in the early stages of development. It hijacks a recently discovered genetic trick that bacteria use to fight off viruses, known by the acronym Crispr. One of the Crispr enzymes in particular, Cas9, the scientists report, can be used for "precise cleavage"-accurate DNA cutting-in human and mouse cells. Moreover, both Talens and Crispr can be aimed at several sites simultaneously-greatly accelerating the process of gene editing.

Precise, multiple editing of DNA has arrived. "I'm expecting a revolution in genetics," says Dr. Fahrenkrug.

Here's Mark Lynas on those who still oppose GM food: "I look forward to their opening up an honest and self-critical debate on this, rather than attacking others like myself who challenge green orthodoxy where it likely harms society and the environment."

Here's Mark Lynas on wind power: "Matt Ridley's massive Spectator anti-wind rant seems completely fact-free. Any references to back this up, @mattwridley?" [There were scores of facts and references, starting with my assertion that wind power provides 0.3% of the UK's total energy, a fact that Lynas challenged, then called specious, then conceded].

Yes, indeed, Mark, I challenge green orthodoxy on wind power precisely because I think it "likely harms society and the environment", and am indeed attacked for it - by you.

You are welcome to the ranks of those who challenge green orthodoxy; glad you eventually joined us. I look forward to you re-examining some other green orthodoxies. I look forward to you "opening up an honest and self-critical debate" on wind power.

Did you know that the Earth is getting greener, quite literally? Satellites are now confirming that the amount of green vegetation on the planet has been increasing for three decades. This will be news to those accustomed to alarming tales about deforestation, overdevelopment and ecosystem destruction.

This possibility was first suspected in 1985 by Charles Keeling, the scientist whose meticulous record of the content of the air atop Mauna Loa in Hawaii first alerted the world to the increasing concentration of carbon dioxide in the atmosphere. Mr. Keeling's famous curve showed not only a year-by-year increase in carbon dioxide levels but a season-by-season oscillation in the concentration.

During summers in the Northern Hemisphere, the Earth breathes in carbon dioxide as green plants (most of which are north of the equator) absorb the gas and turn it into carbohydrate. In the northern winter, the Earth breathes the gas out again, as the summer's leaves rot.

Mr. Keeling and colleagues noticed that the depth of the breathing had increased in Hawaii by 20% [by 1995] since the 1960s: The Earth was taking in more carbon dioxide each northern summer and giving out more each winter. Since the inhalation is done by green leaves, they reasoned, the amount of greenery on the planet must be growing larger. In the 1980s forest biologists started to report striking increases in the growth rates of trees and the density of forests: in Douglas firs in British Columbia, Scots pines in Finland, bristlecone pines in Colorado and even tropical rain forests.

Around the same time, a NASA scientist named Compton Tucker found that he could map global vegetation changes by calculating a "Normalized Difference Vegetation Index" (NDVI) from the data produced by a satellite sensor. The data confirmed Mr. Keeling's suspicion: Greenery was on the increase. At first, this was thought to be a northern phenomenon, caused by faster growth in the great spruce and birch forests of Siberia and Canada, but the satellites showed it was happening all over the world and especially strongly in the Amazon and African rain forests.

Using the NDVI, one team this year reported that "over the last few decades of the 20th century, terrestrial ecosystems acted as net carbon sinks," i.e., they absorbed more carbon than they were emitting, and "net greening was reported in all biomes," though the effect had slowed down in recent years. see also here.

The latest and most detailed satellite data, which is yet to be published but was summarized in an online lecture last July by Ranga Myneni of Boston University, confirms that the greening of the Earth has now been going on for 30 years. Between 1982 and 2011, 20.5% of the world's vegetated area got greener, while just 3% grew browner; the rest showed no change.

What explains this trend? Man-made nitrogen fertilizer causes crops to grow faster, but it is having little effect on forests. There are essentially two possibilities: climate and carbon dioxide itself. Warmer, wetter weather should cause more vegetation to grow. But even without warming, an increase in carbon dioxide should itself accelerate growth rates of plants. CO2 is a scarce resource that plants have trouble scavenging from the air, and plants grow faster with higher levels of CO2 to inhale.

Dr. Myneni reckons that it is now possible to distinguish between these two effects in the satellite data, and he concludes that 50% is due to "relaxation of climate constraints," i.e., warming or rainfall, and roughly 50% is due to carbon dioxide fertilization itself. In practice, the two interact. A series of experiments has found that plants tolerate heat better when CO2 levels are higher.

The inescapable if unfashionable conclusion is that the human use of fossil fuels has been causing the greening of the planet in three separate ways: first, by displacing firewood as a fuel; second, by warming the climate; and third, by raising carbon dioxide levels, which raise plant growth rates.

Post-script:

In a comprehensive survey of the litertature on this subject, which I recommend as a short cut to many of the individual studies and the continent-by-continent details, Craig Idso reaches the following conclusions:

In the ensuing report we present a meta-analysis of the peer-reviewed scientific literature, examining how the productivities of Earth's plants have responded to the 20th and now 21st century rise in global temperature and atmospheric CO2, a rise that climate alarmists claim is unprecedented over thousands of years (temperature) to millions of years (CO2 concentration). Based on that analysis, we find the following:

 The productivity of the planet's terrestrial biosphere, on the whole, has been increasing with time, revealing a great greening of the Earth that extends throughout the entire globe.

 Satellite-based analyses of net terrestrial primary productivity (NPP) reveal an increase of around 6-13% since the 1980s.

 There is no empirical evidence to support the model-based claim that future carbon uptake by plants will diminish on a global scale due to rising temperatures. In fact, just the opposite situation has been observed in the real world.

 Earth's land surfaces were a net source of CO2-carbon to the atmosphere until about 1940. From 1940 onward, however, the terrestrial biosphere has become, in the mean, an increasingly greater sink for CO2-carbon.

 Over the past 50 years, for example, global carbon uptake has doubled from 2.4 ± 0.8 billion tons in 1960 to 5.0 ± 0.9 billion tons in 2010 (see figure below).

 The observed global greening has occurred in spite of all the many real and imagined assaults on Earth's vegetation that have occurred over the past several decades, including wildfires, disease, pest outbreaks, deforestation, and climatic changes in temperature and precipitation, more than compensating for any of the negative effects these phenomena may have had on the global biosphere.

 There is compelling evidence that the atmosphere's rising CO2 content - which alarmists consider to be the chief culprit behind all of their concerns about the future of the biosphere (via the indirect threats they claim it poses as a result of CO2-induced climate change) - is most likely the primary cause of the observed greening trends.

 In the future, Earth's plants should be able to successfully adjust their physiology to accommodate a warming of the magnitude and rate-of-rise that is typically predicted by climate models to accompany the projected future increase in the air's CO2 content. Factoring in plant productivity gains that will occur as a result of the aerial fertilization effect of the ongoing rise in atmospheric CO2, plus its accompanying transpiration- reducing effect that boosts plant water use efficiency, the world's vegetation possesses an ideal mix of abilities to reap a tremendous benefit in the years and decades to come.

A "rational optimist" like me thinks the world will go on getting better for most people at a record rate, not because I have a temperamental or ideological bent to good cheer but because of the data. Poverty, hunger, population growth rates, inequality, and mortality from violence, disease and weather - all continue to plummet on a global scale.

But a global optimist can still be a regional pessimist. When asked what I am pessimistic about, I usually reply: bureaucracy and superstition. Using those two tools, we Europeans seem intent on making our future as bad as we can. Like mandarins at the court of the Ming emperors or viziers at the court of Abbasid caliphs, our masters seem determined to turn relative into absolute decline. It is entirely possible that ten years from now the world as a whole will be 50 per cent richer, but Europeans will be 50 per cent poorer.

Not that the world economy is a zero-sum game. It is a good thing if Africans and Latin Americans join Asians in getting richer at breakneck pace, as many now seem to be doing, even if we don't join in: not only because want and misery are bad whoever they happen to, but also because if others grow productive and inventive they can supply us with valuable goods and services. Why should the development of new antibiotics or thorium nuclear power remain a burden exclusively on the shoulders of Western taxpayers?

Even so, relative decline can be painful. Spanish people are richer and live longer than when their silver-sated conquistador ancestors strutted the European stage, but I am sure it does not feel like it to an unemployed youth in Bilbao. Whatever happens, we Europeans will probably have to get used to watching Asians book the best restaurants and launch the biggest aircraft carriers in the years ahead.

Absolute decline is far more scary. If Europe cannot rediscover how to grow its economy, then it will have to default on its vast debts, either directly or by inflation. Either way savers will be poorer, tax receipts will be lower and spending on schools and hospitals and roads will be lower: genuine austerity.

As the MP Douglas Carswell reminds us in his book The End of Politics, here in Britain we have public and private debts that are five times our annual economic output; we are spending £46 out of every £100 we earn to buy government - a product that, unlike most, delivers less output for more cost each year. As the Ming empire found out, the more government you buy, the less economic activity you get. A Fujian travelling salesman in 1400 was enmeshed in such a tangled bureaucracy that he could neither travel nor sell without bribes and permits, and he had to submit a monthly inventory of his stocks to the emperor.

Sound familiar? Every small businessman I talk to these days has a horror story to tell about the delays and costs that have been visited upon him by planners, inspectors, officials and consultees. Using the excuse of "cuts", the bureaucracy is taking even longer to make decisions than five years ago. In the time it has taken Britain's Government to decide whether to allow a fifth exploratory shale gas well to be drilled in Lancashire, and from the same standing start, the same investors have drilled 72 producing wells in Argentina. That the country of Watt and Stephenson should look a potential cheap-energy gift horse in the mouth in this way is staggering to this jaded optimist.

From ancient Egypt to modern North Korea, always and everywhere, economic planning and control have caused stagnation; from ancient Phoenicia to modern Vietnam, economic liberation has caused prosperity. In the 1960s, Sir John Cowperthwaite, the financial secretary of Hong Kong, refused all instruction from his LSE-schooled masters in London to plan, regulate and manage the economy of his poor and refugee-overwhelmed island. Set merchants free to do what merchants can, was his philosophy. Today Hong Kong has higher per capita income than Britain.

In July 1948 Ludwig Erhard, director of West Germany's economic council, abolished food rationing and ended all price controls on his own initiative. General Lucius Clay, military governor of the US zone, called him and said: "My advisers tell me what you have done is a terrible mistake. What do you say to that?" Erhard replied: "Herr General, pay no attention to them! My advisers tell me the same thing." The German economic miracle was born that day; Britain kept rationing for six more years. Where are Europe's Cowperthwaites and Erhards today?

A growth-preventing bureaucracy is not the only thing suppressing enterprise in Europe. Superstition is also playing a part, as it has done in past episodes of economic decline. The great flowering of Arab prosperity and culture under the Abbasids was brought to an end with the burning of books, the shutting down of inquiry and a mistrust of novelty.

Again there are echoes. Many of the ideas that led to the genetic modification of plants - which has boosted yields, cut insecticide use, saved fuel and soil, and helped the poorest farmers - were pioneered in this country. Yet today there is almost none of this work done in Britain and none of its boons are permitted to farmers and their customers. The labs are ghostly quiet. Why? Entirely because of neophobic superstition that has animated reactionary elites into opposing change on the basis of myths peddled by green mystics. (The biggest superstition of all is surely the worship of the euro: the sacrifice of growth, youth and truth at the altar of a mere currency.) By contrast, America, for all its fiscal incontinence, is still friendly to enterprise and open to novelty, as any time spent in Silicon Valley will prove. To avoid the fate of Ming China Europe needs to rediscover economic rationality.

Knot No. 1 is the chick-and-egg problem of energy. Living things burn energy at a furious rate to stay alive. Every time a bacterium divides, it uses up 50 times its own mass of energy-currency molecules (called ATP)-and that's with efficient and specialized modern protein machinery to do the job. When starting out, life would have been a far more wasteful process, needing more energy, yet would have had none of its modern machinery to harness or store energy.

Knot No. 2 is entropy. Life uses energy to make order out of chaos. So the putative location preferred by previous evolutionists-Alexander Oparin's primordial soup in Charles Darwin's "warm little pond" with a little lightning-is just too unconstrained: Life would just keep dissolving away before it got started.

Before the cell existed, life needed a controlled supply of concentrated energy in a confined space. Comparing gene sequences leads to the conclusion that at the very root of life's family tree lie the "chemi-osmotic" bacteria and archaea (single-celled creatures like bacteria). These are microbes that effectively charge their electrochemical batteries by converting carbon dioxide into methane or the organic compound acetate.

Where did they originate? In 2000 explorers found vents in the mid-Atlantic, the Lost City hydrothermal field, that are quite unlike the better known hot, acidic "black smoker" deep-sea vents: They last for much longer, are highly alkaline and modestly warm.

Now Nick Lane of University College London and William Martin of Heinrich Heine University in Düsseldorf, Germany, have concluded that this environment carries uncanny echoes of life's method of storing energy.

Cells store energy by pumping charged "ions" usually of sodium or hydrogen across membranes, effectively creating an electrical voltage. This is a peculiar but universal feature of life, whose ubiquity has never been explained. The scientists think it was originally borrowed from vents like those at Lost City.

Four billion years ago, at such a vent, hot alkaline fluid rich in hydrogen met acidic oceans saturated in carbon dioxide. There would have been natural proton gradients across the thin iron-nickel-sulfur walls of the vents, with a voltage very like the membrane potential of modern chemi-osmotic microbes. The authors write: "In our view-and given the near universality of proton gradients across life-this is no coincidence."

Today's microbes that live at these hydrothermal vents use proton gradients to add electrons to a protein called ferredoxin, which in turn converts carbon dioxide into organic molecules needed for growth. The vents' rocks are riddled with interconnected micro-pores, where these organic chemicals might once have accumulated, some of them further accelerating the reaction.

Drs. Lane and Martin have an ingenious suggestion for how life then became free-living. A geochemical proton gradient could freely drive a biochemical sodium-ion pump, in effect allowing a membrane to exclude sodium, forming another electrical energy storage mechanism-one that would have been much more reliable as the first leaky membranes began to seal off into cells. This would explain why many primitive energy proteins use both sodium and hydrogen (protons) indiscriminately, and why all living cells have less sodium in them than seawater.

In effect, the energy reactions that happen chemically at alkaline hydrothermal vents were borrowed and refined by living cells, which is why there are so many chemical similarities today.

Here are:

1. The article

2. An essay by Nic Lewis expanding on many of the points in the article.

3. My response to one of the critiques of the article

Forget the Doha climate jamboree that ended earlier this month. The theological discussions in Qatar of the arcana of climate treaties are irrelevant. By far the most important debate about climate change is taking place among scientists, on the issue of climate sensitivity: How much warming will a doubling of atmospheric carbon dioxide actually produce? The Intergovernmental Panel on Climate Change has to pronounce its answer to this question in its Fifth Assessment Report next year.

The general public is not privy to the IPCC debate. But I have been speaking to somebody who understands the issues: Nic Lewis. A semiretired successful financier from Bath, England, with a strong mathematics and physics background, Mr. Lewis has made significant contributions to the subject of climate change.

Mr. Lewis tells me that the latest observational estimates of the effect of aerosols (such as sulfurous particles from coal smoke) find that they have much less cooling effect than thought when the last IPCC report was written. The rate at which the ocean is absorbing greenhouse-gas-induced warming is also now known to be fairly modest. In other words, the two excuses used to explain away the slow, mild warming we have actually experienced-culminating in a standstill in which global temperatures are no higher than they were 16 years ago-no longer work.

In short: We can now estimate, based on observations, how sensitive the temperature is to carbon dioxide. We do not need to rely heavily on unproven models. Comparing the trend in global temperature over the past 100-150 years with the change in "radiative forcing" (heating or cooling power) from carbon dioxide, aerosols and other sources, minus ocean heat uptake, can now give a good estimate of climate sensitivity.

The conclusion-taking the best observational estimates of the change in decadal-average global temperature between 1871-80 and 2002-11, and of the corresponding changes in forcing and ocean heat uptake-is this: A doubling of CO2 will lead to a warming of 1.6°-1.7°C (2.9°-3.1°F).

This is much lower than the IPCC's current best estimate, 3°C (5.4°F).

Mr. Lewis is an expert reviewer of the recently leaked draft of the IPCC's WG1 Scientific Report. The IPCC forbids him to quote from it, but he is privy to all the observational best estimates and uncertainty ranges the draft report gives. What he has told me is dynamite.

Given what we know now, there is almost no way that the feared large temperature rise is going to happen. Mr. Lewis comments: "Taking the IPCC scenario that assumes a doubling of CO2, plus the equivalent of another 30% rise from other greenhouse gases by 2100, we are likely to experience a further rise of no more than 1°C."

A cumulative change of less than 2°C by the end of this century will do no net harm. It will actually do net good-that much the IPCC scientists have already agreed upon in the last IPCC report. Rainfall will increase slightly, growing seasons will lengthen, Greenland's ice cap will melt only very slowly, and so on.

Some of the best recent observationally based research also points to climate sensitivity being about 1.6°C for a doubling of CO2. An impressive study published this year by Magne Aldrin of the Norwegian Computing Center and colleagues gives a most-likely estimate of 1.6°C. Michael Ring and Michael Schlesinger of the University of Illinois, using the most trustworthy temperature record, also estimate 1.6°C.

The big question is this: Will the lead authors of the relevant chapter of the forthcoming IPCC scientific report acknowledge that the best observational evidence no longer supports the IPCC's existing 2°-4.5°C "likely" range for climate sensitivity? Unfortunately, this seems unlikely-given the organization's record of replacing evidence-based policy-making with policy-based evidence-making, as well as the reluctance of academic scientists to accept that what they have been maintaining for many years is wrong.

***

How can there be such disagreement about climate sensitivity if the greenhouse properties of CO2 are well established? Most people assume that the theory of dangerous global warming is built entirely on carbon dioxide. It is not.

There is little dispute among scientists about how much warming CO2 alone can produce, all other things being equal: about 1.1°-1.2°C for a doubling from preindustrial levels. The way warming from CO2 becomes really dangerous is through amplification by positive feedbacks-principally from water vapor and the clouds this vapor produces.

It goes like this: A little warming (from whatever cause) heats up the sea, which makes the air more humid-and water vapor itself is a greenhouse gas. The resulting model-simulated changes in clouds generally increase warming further, so the warming is doubled, trebled or more.

That assumption lies at the heart of every model used by the IPCC, but not even the most zealous climate scientist would claim that this trebling is an established fact. For a start, water vapor may not be increasing. A recent paper from Colorado State University concluded that "we can neither prove nor disprove a robust trend in the global water vapor data." And then, as one Nobel Prize-winning physicist with a senior role in combating climate change admitted to me the other day: "We don't even know the sign" of water vapor's effect-in other words, whether it speeds up or slows down a warming of the atmosphere.

Climate models are known to poorly simulate clouds, and given clouds' very strong effect on the climate system-some types cooling the Earth either by shading it or by transporting heat up and cold down in thunderstorms, and others warming the Earth by blocking outgoing radiation-it remains highly plausible that there is no net positive feedback from water vapor.

If this is indeed the case, then we would have seen about 0.6°C of warming so far, and our observational data would be pointing at about 1.2°C of warming for the end of the century. And this is, to repeat, roughly where we are.

The scientists at the IPCC next year have to choose whether they will admit-contrary to what complex, unverifiable computer models indicate-that the observational evidence now points toward lukewarm temperature change with no net harm. On behalf of all those poor people whose lives are being ruined by high food and energy prices caused by the diversion of corn to biofuel and the subsidizing of renewable energy driven by carboncrats and their crony-capitalist friends, one can only hope the scientists will do so.

Addendum:

Here is Nic Lewis's detailed account of his reasoning:

Guest post by Nic Lewis

There has been much discussion on climate blogs of the leaked IPCC AR5 Working Group 1 Second Order Draft (SOD). Now that the SOD is freely available, I can refer to the contents of the leaked documents without breaching confidentiality restrictions.

I consider the most significant - but largely overlooked - revelation to be the substantial reduction since AR4 in estimates of aerosol forcing and uncertainty therein. This reduction has major implications for equilibrium climate sensitivity (ECS). ECS can be estimated using a heat balance approach - comparing the change in global temperature between two periods with the corresponding change in forcing, net of the change in global radiative imbalance. That imbalance is very largely represented by ocean heat uptake (OHU).

Since the time of AR4, neither global mean temperature nor OHU have increased, while the IPCC's own estimate of the post-1750 change in forcing net of OHU has increased by over 60%. In these circumstances, it is extraordinary that the IPCC can leave its central estimate and 'likely' range for ECS unchanged.

I focused on this point in my review comments on the SOD. I showed that using the best observational estimates of forcing given in the SOD, and the most recent observational OHU estimates, a heat balance approach estimates ECS to be 1.6-1.7°C - well below the 'likely' range of 2‑4.5°C that the SOD claims (in Section 10.8.2.5) is supported by the observational evidence, and little more than half the best estimate of circa 3°C it gives.

The fact that ECS, as derived using the new aerosol forcing estimates and a heat balance approach, appears to be far lower than claimed in the SOD is highlighted in an  article by Matt Ridley in the Wall Street Journal, which uses my calculations. There was not space in that article to go into the details - including the key point that the derived ECS estimate is very well constrained - so I am doing so here.

How does the IPCC arrive at its estimated range for climate sensitivity?

Methods used to estimate ECS range from:

(i) those based wholly on simulations by complex climate models (GCMs), the characteristics of which are only very loosely constrained by climate observations, through

(ii) those using simpler climate models whose key parameters are intended to be constrained as tightly as possible by observations, to

(iii) those that rely wholly or largely on direct observational data.

The IPCC has placed a huge emphasis on GCM simulations, and the ECS range exhibited by GCMs has played a major role in arriving at the IPCC's 2-4.5°C 'likely' range for ECS. I consider that little credence should be given to estimates for ECS derived from GCM simulations, for various reasons, not least because there can be no assurance that any of the GCMs adequately reflect all key climate processes. Indeed, since in general GCMs significantly overestimate aerosol forcing compared with observations, they need to embody a high climate sensitivity or they would underestimate historical warming and be consigned to the scrapheap. Observations, not highly complex and unverifiable models, should be used to estimate the key properties of the climate system.

Most observationally-constrained studies use instrumental data, for good reason. Reliance cannot be placed on paleoclimate proxy-based estimates of ECS - the AR4 WG1 report concluded (Box 10.2) that uncertainties in Last Glacial Maximum studies are just too great, and the only probability density function (PDF) for ECS it gave from a last millennium proxy-based study contained little information.

Because it has historically been difficult to estimate ECS purely from instrumental observations, a standard estimation method is to compare observations of key observable climate variables, such as zonal temperatures and OHU, with simulations of their evolution by a relatively simple climate model with adjustable parameters that represent, or are calibrated to, ECS and other key climate system properties. A number of such 'inverse' studies, of varying quality, have been performed; I refer later to various of these. But here I estimate ECS using a simple heat balance approach, which avoids dependence on models and also has the advantage of not involving choices about niceties such as truncation parameters and Bayesian priors, which can have a major impact on ECS estimation.

Aerosol forcing in the SOD - a composite estimate is used, not the best observational estimate

Before going on to estimating ECS using a heat balance approach, I should explain how the SOD treats forcing estimates, in particular those for aerosol forcing. Previous IPCC reports have just given estimates for radiative forcing (RF). Although in a simple world this could be a good measure of the effective warming (or cooling) influence of every type of forcing, some forcings have different efficacies from others. In AR5, this has been formalised into a measure, adjusted forcing (AF), intended better to reflect the total effect of each type of forcing. It is more appropriate to base ECS estimates on AF than on RF.

The main difference between the AF and RF measures relates to aerosols. In addition, the AF uncertainty for well-mixed greenhouse gases (WMGG) is double that for RF. Table 8.7 of the SOD summarises the AR5 RF and AF best estimates and uncertainty ranges for each forcing agent, along with RF estimates from previous IPCC reports. The terminology has changed, with direct aerosol forcing renamed aerosol-radiation interactions (ari) and the cloud albedo (indirect) effect now known as aerosol-cloud interactions (aci).

Table 8.7 shows that the best estimate for total aerosol RF (RFari+aci) has fallen from −1.2 W/m² to −0.7 W/m² since AR4, largely due to a reduction in RFaci, the uncertainty band for which has also been hugely reduced. It gives a higher figure, −0.9 W/m², for AFari+aci. However, −0.9 W/m² is not what the observations indicate: it is a composite of observational, GCM-simulation/aerosol model derived, and inverse estimates. The inverse estimates - where aerosol forcing is derived from its effects on observables such as surface temperatures and OHU - are a mixed bag, but almost all the good studies give a best estimate for AFari+aci well below −0.9 W/m²: see Appendix 1 for a detailed analysis.

It cannot be right, when providing an observationally-based estimate of ECS, to let it be influenced by including GCM-derived estimates for aerosol forcing - a key variable for which there is now substantial observational evidence. To find the IPCC's best observational (satellite-based) estimate for AFari+aci, one turns to Section 7.5.3 of the SOD, where it is given as −0.73 W/m² with a standard deviation of 0.30 W/m². That is actually the same as the Table 8.7 estimate for RFari+aci, except for the uncertainty range being higher. Table 8.7 only gives estimated AFs for 2011, but Figure 8.18 gives their evolution from 1750 to 2010, so it is possible to derive historical figures using the recent observational AFari+aci estimate as follows.

The values in Figure 8.18 labelled 'Aer-Rad Int.' are actually for RFari, but that equals the purely observational estimate for AFari (−0.4 W/m² in 2011), so they can stand. Only the values labelled 'Aer-Cld Int.', which are in fact the excess of AFari+aci over RFari, need adjusting (scaling down by (0.73−0.4)/(0.9−0.4), all years) to obtain a forcing dataset based on a purely observational estimate of aerosol AF rather than the IPCC's composite estimate. It is difficult to digitise the Figure 8.18 values for years affected by volcanic eruptions, so I have also adjusted the widely-used RCP4.5 forcings dataset to reflect the Section 7.5.3 observational estimate of current aerosol forcing, using Figure 8.18 and Table 8.7 data to update the projected RCP4.5 forcings for 2007-2011 where appropriate. The result is shown below.

The adjustment I have made merely brings estimated forcing into line with the IPCC's best observationally-based estimate for AFari+aci. But one expert on the satellite observations, Prof. Graeme Stephens, has stated that AFaci is at most ‑0.1 W/m², not ‑0.33 W/m² as implied by the IPCC's best observationally-based estimates: see  here and slide 7 of the linked GEWEX presentation. If so, ECS estimates should be lowered further.

Reworking the Gregory et al. (2002) heat balance change derived estimate of ECS

The best known study estimating ECS by comparing the change in global mean temperature with the corresponding change in forcing, net of that in OHU, is Gregory et al. (2002). This was one of the studies for which an estimated PDF for ECS was given in AR4. Unfortunately, ten years ago observational estimates of aerosol forcing were poor, so Gregory used a GCM-derived estimate. In July 2011 I wrote an open letter to Gabi Hegerl, joint coordinating lead author of the AR4 chapter in which Gregory 02 was featured, pointing out that its PDF was not computed on the basis stated in AR4 (a point since conceded by the IPCC), and also querying the GCM-derived aerosol forcing estimate used in Gregory 02. Some readers may recall my blog post at Climate Etc. featuring that letter,  here. Using the GISS forcings dataset, and corrected Levitus et al. (2005) OHU data, the 1861-1900 to 1957-1994 increase in Q − F (total forcing - OHU) changed from 0.20 to 0.68 W/m². Dividing 0.68 W/m² into ΔT', the change in global surface temperature, being 0.335°C, and multiplying by 3.71 W/m² (the estimated forcing from a doubling of CO2 concentration) gives a central estimate (median) for ECS of 1.83°C.

I can now rework my Gregory 02 calculations using the best observational forcing estimates, as reflected in Figure 8.18 with aerosol forcing rescaled as described above. The change in Q - F becomes 0.85 W/m². That gives a central estimate for ECS of 1.5°C.

An improved ECS estimate from the change in heat balance over 130 years

The 1957-1994 period used in Gregory 02 is now rather dated. Moreover, using long time periods for averaging makes it impossible to avoid major volcanic eruptions, which involve uncertainty as to the large forcing excursions involved and their effects. I will therefore produce an estimate based on decadal mean data, for the decade to 1880 and for the most recent decade, to 2011. Although doing so involves an increased influence of internal climate variability on mean surface temperature, it has several advantages:

a) neither decade was significantly affected by volcanic activity;

b) neither decade encompassed exceptionally large ENSO events, such as the 1997/98 El Nino, and average ENSO conditions were broadly neutral in both decades (arguably with a greater tendency towards warm El Nino conditions in the recent decade); and

c) the two decades are some 130 years apart, and therefore correspond to similar positions in the 60-70 year quasi-periodic AMO cycle (which appears to have a peak-to-peak influence on global mean temperature of the order of 0.1°C).

Since estimates of OHU have become much more accurate during the latest decade, as the ARGO network of diving buoys has come into action, the loss of accuracy by measuring OHU only over the latest decade is modest.

I summarise here my estimates of the changes in decadal mean forcing, heat uptake and global temperature between 1871-1880 and 2002-2011, and related uncertainties. Details of their derivations are given in Appendix 2.

Now comes the fun bit, putting all the figures together. The best estimate of the change from 1871-1880 to 2002-2011 in decadal mean adjusted forcing, net of the Earth's heat uptake, is 2.09 − 0.43 = 1.66 W/m². Dividing that into the estimated temperature change of 0.727°C and multiplying by 3.71 W/m² gives an estimated climate sensitivity of 1.62°C, close to that from reworking Gregory 02.

Based on the estimated uncertainties, I compute a 5-95% confidence interval for ECS of 1.03‑2.83°C - see Appendix 3. That implies a >95% probability that ECS is below the IPCC's central estimate of 3°C.

ECS estimates from recent studies - good ones…

As well as this simple estimate from heat balance implying a best estimate for ECS of approximately 1.6°C, and the reworking of the Gregory 02 results suggesting a slightly lower figure, two good quality recent observationally-constrained studies using relatively simple hemispheric-resolving models also point to climate sensitivity being about 1.6°C:

§ Aldrin et al. (2012), an impressively thorough study, gives a most likely estimate for ECS of 1.6°C and a 5-95% range of 1.2-3.5°C.

• Ring et al. (2012) also estimates ECS as 1.6°C, using the HadCRUT4 temperature record (1.45°C to 2.01°C using other records).

And the only purely observational study featured in AR4, Forster & Gregory (2006), which used satellite observations of radiation entering and leaving the atmosphere, also gave a best estimate of 1.6°C, with a 95% upper bound of 4.1°C.

and poor ones…

Most of the instrumental-observation constrained studies featured in IPCC reports that give PDFs for ECS peaking at significantly over 2°C have some identifiable deficiency. Two such studies were featured in Figure 9.21 of AR4 WG1: Forest 06 and Knutti 02. Forest 06 has several statistical errors (see  here) and other problems. Knutti 02 used a weak statistical procedure and an arbitrary combination of five ocean models, and there is little information content in its probabilistic ECS estimate.

Five of the PDFs for ECS from 20th century studies featured in Figure 10.19 of the AR5 SOD peak significantly above 2°C:

• one is Knutti 02;
• three are various cases from Libardoni and Forest (2011), a study that suffers the same deficiencies as Forest 06;
• one is from Olson et al. (2012); the Olson PDF, like Knutti 02′s, is extremely wide and contains almost no information.

Conclusions

In the light of the current observational evidence, in my view 1.75°C would be a more reasonable central estimate for ECS than 3°C, perhaps with a 'likely' range of around 1.25-2.75°C.

Nic Lewis

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Appendix 1: Inverse estimates of aerosol forcing - the expert range largely reflects the poor studies

The AR5 WG1 SOD composite AFari+aci estimate of −0.9 W/m² is derived from mean estimates from satellite observations (−0.73 W/m²), GCMs (−1.45 W/m² from AR4+AR5 models including secondary processes, −1.08 W/m² from CMIP5/ACCMIP models) and an "expert" range of −0.68 to −1.52 W/m² from combined inverse estimates. These figures correspond to box-plots in the lower panel of Figure 7.19. One of the inverse studies cited hasn't yet been published and I haven't been able to obtain it, but I have examined the other twelve studies.

Because of its strong asymmetry between the northern and southern hemispheres, in order to estimate aerosol forcing with any accuracy using inverse methods it is essential to use a model that, at a minimum, resolves the two hemispheres separately. Only seven of the twelve studies do so. Of the other five:

• one is just a survey and derives no estimate itself;
• one (Gregory 02) merely uses an AOGCM-derived estimate of a circa 100-year change in aerosol forcing, without itself deriving any estimate;
• three are based on global-mean only data (with two of them assuming an ECS of 3°C when estimating aerosol forcing).

One of the seven potentially useful studies is based on GCM simulations, which I consider to be untrustworthy. A second does not estimate aerosol forcing over 90S-28S, and concludes that over 1976-2007 it has been large and negative over 28S-28N and large and positive over 28N-60N, the opposite of what is generally believed. A third study is Andronova and Schlesinger (2001), which it turns out had a serious code error. Its estimate of −0.54 to ‑1.30 W/m² falls to −0.42 to −0.99 W/m² when using the corrected model (Ring et al., 2012). Three of the other studies, all using four latitude zones, estimate aerosol forcing to be even lower: in the ranges −0.14 to −0.74, −0.3 to −0.95 and −0.19 to −0.83 W/m². The final study estimates it to be around or slightly above ‑1 W/m², but certainly below ‑1.5 W/m². One recent inverse estimate that the SOD omits is −0.7 W/m² (mean - no uncertainty range given) from Aldrin et al. (2012).

In conclusion, I wouldn't hire the IPCC's experts if I wanted a fair appraisal of the inverse studies. A range of −0.2 to −1.3 W/m² looks more reasonable - and as it happens, is centred almost exactly on the mean of the estimates derived from satellite observations.

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Appendix 2: Derivation of the changes in decadal mean global temperature, forcing and heat uptake

Since it extends back before 1880 and includes a correction to sea surface temperatures in the mid-20th century, I use HadCRUT4 global mean temperature data, available as annual data  here. The difference between the mean for the decade 2002-2011 and that for 1871-1880 is 0.727°C. The uncertainty in that temperature change is tricky to work out because the various error sources are differently correlated in time. Adding the relevant years' total uncertainty estimates for the HadCRUT4 21-year smoothed decadal data (estimated 5-95% ranges 0.17°C and 0.126°C), and very generously assuming the variance uncertainty scales inversely with the number of years averaged, gives an error standard deviation for the change in decadal temperature of 0.08°C (all uncertainty errors are assumed to be normally distributed, and independent except where otherwise stated). There is also uncertainty arising from random fluctuations in the internal state of the climate. Surface temperature simulations from a GCM control run suggest that error source could add a further error standard deviation of 0.08°C for both decades. However, the matching of their characteristics as set out in the main text, points a) to c), and the fact that some fluctuations will be reflected in OHU, suggests a reduction from the 0.11°C error standard deviation implied by adding two 0.08°C standard deviations in quadrature, say increasing halfway, to 0.095°C. Adding that to the observational error standard deviation of 0.08°C gives a total standard deviation of 0.124°C.

The change between 1871‑1880 and 2002-2011 in decadal mean AF, with aerosol forcing scaled to reflect the best recent observational estimates, is 2.09 W/m², taking the average of the Figure 8.18 and RCP4.5 derived estimates (which are both within about 1% of this figure). The total AF uncertainty estimate of ± 0.87 W/m² in Table 8.7 equates to an error standard deviation of 0.44 W/m², which is taken as applying for 2002-2011. Using the observational aerosol forcing error estimate given in Section 7.5.3 instead of the corresponding Table 8.7 uncertainty range gives the same result. Although there would be some uncertainty in the small 1871-1880 mean forcing estimate, the error therein will be strongly correlated with that for 2002-2011. That is because much of the uncertainty relates to the relationships between:

§ concentrations of WMGG and the resulting forcing

§ emissions of aerosols and the resulting forcing,

the respective fractional errors in which are common to both periods. Therefore, the error standard deviation for the change in forcing between 1871-1880 and 2002-2011 could well be smaller than that for the forcing in 2002-2011. However, for simplicity, I assume that it is the same. Finally, I add an error standard deviation of 0.05 W/m² for uncertainty in volcanic forcing in 1871-1880 and a further 0.05 W/m² for uncertainty therein in 2002-2011, small though volcanic forcing was in both decades. Solar forcing uncertainty is included in Table 8.7. Summing the uncertainties, the total AF change error standard deviation is 0.45 W/m².

I estimate 2002-2011 OHU from a regression over 2002-2011 of 0-2000 m pentadal ocean heat content estimates per Levitus et al. (2012), inversely weighting observations by their variance. OHU in the 2000-3000 m layer is estimated to be negligible. After conversion from zeta Joules/year, the trend equates to 0.433 W/m², averaged over the Earth's surface. The standard deviation of the OHU estimate as computed from the regression residuals is 0.031 W/m², but because of the autocorrelation implicit in using overlapping pentadal averages the true figure will be much higher. Multiplying the standard deviation by sqrt(5) provides a crude adjustment for the autocorrelation, bringing the standard deviation to 0.068 W/m². There is no alternative to using GCM-derived estimates of OHU for the 1871-1880 period, since there were no measurements then. I adopt the OHU estimate given in Gregory 02 for the bracketing 1861-1900 period of 0.16 W/m², but deduct only 50% of it to compensate for the Levitus et al. (2012) regression trend implying a somewhat lower 2002-2011 OHU than is given in the SOD. Further, to be conservative, I treble Gregory 02′s optimistic-looking standard deviation, to 0.03 W/m². That implies a change in OHU of 0.353 W/m², with a standard deviation of 0.075 W/m², adding the uncertainty variances. Although Gregory 02 ignored non-ocean heat uptake, some allowance should be made for that and also for any increase in ocean heat content below 3000 m. The (slightly garbled) information in Section 3.2.5 of the SOD implies that 0-3000 m ocean warming accounts for 80-85% of the Earth's total heat uptake, with the error standard deviation for the remainder of the order of 0.03 W/m². Allowing for all components of the Earth's heat uptake implies an estimated change in total heat uptake of 0.43 W/m² with an error standard deviation of 0.08 W/ m². Natural variability in decadal OHU should be the counterpart of natural variability in decadal global surface temperature, so is not accounted for separately.

================================================================

Appendix 3: Derivation of the 5-95% confidence interval

In the table of changes in the variables between 1871-1880 and 2002-2011, I split the AF error standard deviation between that for CO2 and other greenhouse gases (0.291 W/m²), and for all other items (0.343 W/m²). The reason for doing so is this. Almost all the SOD's 10.2% error standard deviation for greenhouse gas AF relates to the AF magnitude that a given change in the greenhouse gas concentration produces, not to uncertainty as to the change in concentration. When estimating ECS, whatever that error is, it will affect equally the 3.71 W/m² estimated forcing from a doubling of equivalent CO2 concentration used to compute the ECS estimate. Most of the uncertainty in the ratio of AF to concentration is probably common to all greenhouse gases. Insofar as it is not, and the relationship between changes in greenhouse gases is different in the future to in the past, then the two AF estimation fractional errors will differ. I ignore that here. As most of the past greenhouse gas forcing is due to CO2 and that is expected to be the case in future, any inaccuracy from doing so should be minor.

So, I estimate a 5-95% confidence interval for ECS as follows. Randomly draw a million realisations from each of the following independent Normal(mean, standard deviation) distributions:

a: AF WMGG uncertainty - before scaling - from N(0,1)

b: Total AF without WMGG uncertainty - from N(2.09,0.343)

c: Earth's heat uptake - from N(0.43,0.08)

d: Surface temperature - from N(0.727,0.124)

and for each quartet of random numbers compute ECS as: 3.71 * (1 + 0.102*a) * d / (0.291*a + b − c).

One then computes a histogram for the million ECS estimates and finds the points below which 5% and 95% of the total estimates lie. The resulting 5-95% range comes out at 1.03 to 2.83°C.

UPDATE: Dr. Judith Curry provides her take on the issue, and endorses the leak:

http://judithcurry.com/2012/12/19/climate-sensitivity-in-the-ar5-sod/

And here is my response to one of the critiques of the Wall Street Journal article:

Joe Romm of ThinkProgress described my Wall Street Journal op-ed http://online.wsj.com/article/SB10001424127887323981504578179291222227104.html as:

riddled with basic math and science errors

Yet he fails to find a single basic math or science error in my piece.

He says I :

can't do simple math

and then fail to produce a single example of my failing to do simple math.

He says I apparently don't know the difference between water vapor and clouds. He produces no evidence for this absurd claim, which is wrong. Water vapor is a gas; clouds are droplets of liquid water that condense from water vapor. I do know the difference.

He quotes a scientist as saying

it is very clear water vapor … is an amplifying effect. It is a very strong warmer for the climate.

I agree. My piece states:

water vapor itself is a greenhouse gas.

So there is no confusion there. At least not on my part.

However, I do discuss the possibility that clouds, formed from water vapor, either amplify or damp warming - and nobody at this stage knows which. This is the point that my physicist informant was making: the consequence of increased temperatures and water vapor in the atmosphere may be changes in clouds that have a cooling effect. You will find few who disagree with this. As the IPCC AR4 said:

Cloud feedbacks remain the largest source of uncertainty.

Joe Romm disagrees with this consensus, saying

The net radiative feedback due to all cloud types is likely positive.

He gives no backing for this dogmatic conclusion. By contrast, Professor Judith Curry of Georgia Tech says (http://judithcurry.com/2012/12/19/climate-sensitivity-in-the-ar5-sod/#more-10669):

The key point is this.  The cloud forcing values are derived from climate models; we have already seen that climate models have some fundamental problems in how clouds are treated (e.g. aerosol-cloud interactions, moist thermodynamics).  So, climate model derived values of cloud forcing should be taken with a grain of salt.   Empirically based determinations of cloud forcing are needed.  At AGU, I spoke with a scientist that has completed such a study, with the paper almost ready for submission.  Punchline:  negative cloud feedback.

Joe Romm quotes Robert Kaufman as saying

"I know of no evidence that would suggest that the temperature effect of sulfur emissions are small."

My piece never claimed that aerosols arising from sulfur emissions had a small effect, however as Nic Lewis points out (http://bishophill.squarespace.com/blog/2012/12/19/why-doesnt-the-ar5-sods-climate-sensitivity-range-reflect-it.html), in the draft AR5 report,

"Table 8.7 shows that the best estimate for total aerosol RF (RFari+aci) has fallen from −1.2 W/m² to −0.7 W/m² since AR4, largely due to a reduction in RFaci, the uncertainty band for which has also been hugely reduced. It gives a higher figure, −0.9 W/m², for AFari+aci. However, −0.9 W/m² is not what the observations indicate: it is a composite of observational, GCM-simulation/aerosol model derived, and inverse estimates."

With regard to the rate of ocean heat absorption, which I wrote was fairly modest, Joe Romm quotes Kevin Trenberth as writing:

"On the contrary there is now very good evidence that a lot of heat is going into the deep ocean in unprecedented ways…"

and then provides a link to an article citing a study estimating the Earth's current heat absorption as 0.5 W/ m².  So what "fairly modest" figure does Nic Lewis use? Actually slightly higher: 0.52 W/m²!

Romm then says:

Ridley apparently doesn't have the first clue what the climate sensitivity means

This is not true. I define sensitivity clearly as the temperature change for a doubling of CO2. I am not talking about the Transient Climate Response, which relates to temperature change only over a 70 year period. There is no confusion at my end.

Romm then says that

Schlesinger notes that an aggressive program of carbon mitigation can limit warming to 2°C and avoid the worst impacts

and that

"It is worth pointing out that there is a healthy debate about Schlesinger's low estimate".

So maybe there is some confusion at Romm's end about what Schlesinger concludes. This is what his paper says (in "Causes of the Global Warming Observed since the 19th Century" in Atmospheric and Climate Science 2012) -

"Additionally, our estimates of climate sensitivity using our SCM and the four instrumental temperature records range from about 1.5 ̊C to 2.0 ̊C. These are on the low end of the estimates in the IPCC's Fourth Assessment Report. So, while we find that most of the observed warming is due to human emissions of LLGHGs, future warming based on these estimations will grow more slowly compared to that under the IPCC's "likely" range of climate sensitivity, from 2.0 ̊C to 4.5 ̊C."

Many other recent papers have come to similar conclusions: For example, Schmittner et al. in Science Dec. 11, 2011 URL http://www.sciencemag.org/content/334/6061/1385.short:

Combining extensive sea and land surface temperature reconstructions from the Last Glacial Maximum with climate model simulations, we estimate a lower median (2.3 K) and reduced uncertainty (1.7 to 2.6 K as the 66% probability range, which can be widened using alternate assumptions or data subsets). Assuming that paleoclimatic constraints apply to the future, as predicted by our model, these results imply a lower probability of imminent extreme climatic change than previously thought.

Meanwhile for transient climate response, similar low estimates are also now being made. See for example Gillett et al.'s 2012 article "Improved constraints on 21st-century warming derived using 160 years of temperature observations" in Geophysical Research Letters at http://www.agu.org/pubs/crossref/2012/2011GL050226.shtml:

Our analysis also leads to a relatively low and tightly-constrained estimate of Transient Climate Response of 1.3-1.8°C, and relatively low projections of 21st- century warming under the Representative Concentration Pathways.

Or Padilla et al.'s 2011 article  "Probabilistic estimated of transient climate sensitivity subject to uncertainty in forcing and natural variability" in the Bulletin of the American Meteorological Association at URL: http://journals.ametsoc.org/doi/abs/10.1175/2011JCLI3989.1:

For uncertainty assumptions best supported by global surface temperature data up to the present time, this paper finds a most likely present-day estimate of the transient climate sensitivity to be 1.6 K, with 90% confidence the response will fall between 1.3 and 2.6 K, and it is estimated that this interval may be 45% smaller by the year 2030. The authors calculate that emissions levels equivalent to forcing of less than 475 ppmv CO2 concentration are needed to ensure that the transient temperature response will not exceed 2 K with 95% confidence.

Mr Romm seems confused about methane outgassing feedbacks, arguing that even if climate sensitivity is low, these may dominate. Suffice to say that in this he has drifted a long way from the consensus.

Mr Romm seems determined to rule out even the possibility of low climate sensitivity in the teeth of strong evidence. I can see why he wishes to do so, his job depending on there being a dangerous future. I do not understand where he gets his certainty.

Finally, Mr Romm throws the term "anti-science" at me, again with no evidence. I cited peer reviewed papers and made the scientific argument that the latest data be considered in estimating sensitivity. That is pro science. What is anti-science is to make false accusations and try to shut down legitimate debate. Hard working people all over the world are now risking their lives as well as their wallets for the consequences of current climate policy (see Indur Goklany's paper "Could biofuel policies increase death and disease in developing countries?" http://www.jpands.org/vol16no1/goklany.pdf). They have a right to ask that those who determine the science behind such policies are open-minded. On the evidence of MrRomm's astonishing outburst, my doubts about this are growing.

It's a brave scientist who dares to announce the turning point of a trend, the top of a graph. A paper published this week does just that, persuasively arguing that a centurieslong trend is about to reverse: the use of land for farming. The authors write: "We are confident that we stand on the peak of cropland use, gazing at a wide expanse of land that will be spared for Nature."

Jesse Ausubel and Iddo Wernick of Rockefeller University, and Paul Waggoner of the Connecticut Agricultural Experiment Station, have reached this conclusion by documenting the gradual "dematerialization" of agriculture. Globally, the production of a given quantity of crop requires 65% less land than it did in 1961, thanks to fertilizers, tractors, pesticides, better varieties and other factors. Even corrected for different kinds of crops, the acreage required is falling at 2% a year.

In the U.S., the total corn yield and the total corn acreage tracked each other in lock step between 1870 and 1940-there was no change in average yield per acre. But between 1940 and 2010, corn production almost quintupled, while the acreage devoted to growing corn fell slightly. Similar divergences appeared later in other countries. Indian wheat production increased fivefold after 1970, while wheat acreage crept up by less than 1.5 times. Chinese corn production rose sevenfold over the same period while corn acreage merely doubled.

Yet the amount of farmland in the world was still rising until recently. The reason is that increased farm productivity has been matched by rising demand for food, driven by population growth and swelling affluence. But the effects of these trends are waning.

Global population growth has slowed markedly in recent years-the rate of change halving since 1970 to about 1% a year today. Growing affluence leads people to eat more calories, and especially more meat. Since it takes two to 10 calories of maize or wheat to produce a calorie of meat, depending on the animal, carnivory demands more cropland. But as a country gets richer, total calorie intake soon levels off, even as wealth continues to rise, and the change in meat consumption decelerates. Chinese meat consumption is now rising less than half as fast as Chinese affluence; Indians have grown richer without taking to meat much at all.

What the Rockefeller team did was plug some highly conservative assumptions about the future into a model and see how much land would be required for growing crops in 2060. Compared with current trends, they assumed population growth will fall more slowly, that affluence will increase faster and that the gluttony of people will rise more rapidly. Conversely, they assumed that farm yields would rise more slowly than they have been doing. This seems highly implausible given that the gigantic continent of Africa seems to be at last embarking on a yield-boosting green revolution as far-reaching as Asia's was.

Even with these cautious assumptions, the researchers find that over the next 50 years people are likely to release from farming a land area "1½ times the size of Egypt, 2½ times the size of France, or 10 Iowas, and possibly multiples of this amount."

Indeed, the authors find that this retreat from the land would have already begun but for one factor so lunatic that they cannot imagine it will not be reversed soon: biofuels. If the world had not decided to subsidize the growing of energy crops on 3.4% of arable land, then absolute declines in the acreage of arable land "would have begun during the last decade." The prospect of "the restoration of vast acreages of Nature" is enticing for nature lovers.

Predictions of peak oil have repeatedly proved wrong. But the factors that made them wrong-productivity and technology-are essentially the ones that make a prediction of peak farmland likely to be right.

On 1 June this year a Mr Andrew Noakes was having lunch in Shropshire when "I thought I heard something. The sound only went on for a few seconds and then it stopped. There was no shaking cutlery or furniture." It was a natural earthquake, bigger than the ones caused by fracking in Lancashire last year. Worldwide there are a million a year of a similar size. Very few are even noticed. A magnitude 2.3 tremor is to a dangerous earthquake as a tiny stream is to the Amazon: the same sort of thing but much less likely to drown you.

By contrast, an earthquake that was 180 million times more energetic killed 80,000 people in 2008 in Sichuan. We now know it was almost certainly man-made, or at least man-triggered. The Zipingpu reservoir, designed to generate hydro-electric power, had been filled with water shortly before the fault beneath it failed.

A report by Fan Xiao, chief engineer of the Regional Geological Survey Team of the Sichuan Geology and Mineral Bureau, analysed 60 studies of the event and concluded that "the mounting body of evidence and analysis indicates that the magnitude 8 earthquake was triggered by the mass loading and increased pore pressure caused by the Zipingpu reservoir".

Admittedly the study was translated and published by Probe International, a Canadian pressure group that campaigns against large dams and is funded partly by the nuclear industry, but others have reached the same conclusion. Professor Christian Klose of Think Geohazards in New York has concluded that the 300m tonnes of water in the Zipingpu reservoir effectively "advanced the clock" on a fault that would not have failed for another 60 years.

That dams cause earthquakes is not a new or far-fetched idea. Dr Klose has catalogued 92 man-made earthquakes, about half of which were caused by dams. One at Koyna in India is still occasionally causing the ground to shake decades after being filled. But think of the implications of this news. It would make the Sichuan earthquake the second largest man-made death toll in a single event, after Hiroshima, but bigger than Nagasaki and Dresden.

To put it unfashionably, the second biggest man-made disaster on record was caused by the search for renewable energy. Geothermal energy, too, can cause earthquakes. Two years ago the city of Basel called a halt to a project intended to extract heat from the rocks deep beneath the city after an earthquake was caused by the drilling. Basel was destroyed by an earthquake in 1356.

[Update: I am told that the company responsible for the Basel event began an intensive programme of hydraulic fracturing at depths up to 5km in contradiction to expert advice and on an active fault boundary. Basel is actually the site of Central Europe's largest ever earthquake in 1356 measuring 7.1 on Richter. The lesson is NOT that geothermal energy -- or dams or gas -- are inherently dangerous but that any of these activities in a seismically sensitive zone near a build-up area are unwise though quite safe elsewhere. Britain is a very very low risk place for big earthquakes. It's the location, not the technology that matters.]

Compared with dams and geothermal projects, the seismic risks of fracking, a procedure that has been used for 60 years to open the pores in rocks to release oil or gas, are not only very small, but extremely well tested. More than 100,000 frackings were carried out in the United States last year and none caused a tremor larger than the Blackpool one-which was in any case barely enough to cause a ripple on your coffee.

If it's earthquakes that worry you, campaign against dams, not gas.

Last week saw a 50th-anniversary celebration in Stockholm of the Nobel Prize for the discovery of DNA's structure. That structure instantly revealed a key secret of life: that an infinitely recombinable sequence of four chemical bases, pairing with each other in two ways, explains life's ability to grow and copy itself. Appropriately, two pairs of people made the discovery: James Watson and Francis Crick in Cambridge, England; and Maurice Wilkins and Rosalind Franklin in London.

But there was a fifth person, who's often forgotten in the telling of the tale: Raymond Gosling. He at last tells part of his own tale in some of the sidebar annotations of a remarkable new book, "The Annotated and Illustrated Double Helix," edited by Alex Gann and Jan Witkowski. The book's text is Dr. Watson's original and brilliant novelistic account of how the discovery was made, but Drs. Gann and Witkowski have added photos, extracts of letters and footnotes to fill out the picture, in the process vindicating almost all of Watson's characterizations.

I spoke to Dr. Gosling at the book's launch in London. He bears no bitterness at being left out of the Nobel Prize. A graduate student at the time, he was working under the direction of others, and his own career went a different way, into medical physics. But it was he, supervised by Maurice Wilkins, who in 1950 first took an X-ray photograph of a DNA fiber, which he had wound around a bent paper clip. Of that moment, he writes: "Those discrete diffraction spots emerging on the film in the developing dish was a truly eureka moment. Maurice and I drank several glasses of his sherry."

It was this photo that electrified Dr. Watson when he saw it presented by Dr. Wilkins at a conference in Naples, Italy. If, as the image implied, the gene had a regular structure, then elucidating that structure might explain its properties. And this quest brought Dr. Watson to (then) Mr. Crick, whom he persuaded to moonlight from the study of proteins and help him tackle DNA.

It was a different photo, taken in May 1952, that led to the solution by giving crucial clues to the dimensions and angles of the DNA molecule. Francis Crick was told about this "Photograph 51" by Jim Watson, who had been shown it by Maurice Wilkins, who had been given it by Rosalind Franklin. It's usually described as her photo, but Raymond Gosling says that he took it as well. By that time he'd been transferred from Dr. Wilkins's to Dr. Franklin's supervision.

Dr. Gosling's frequent omission might annoy a less equable man. Two other Nobel Prizes from the same era-for streptomycin and for pulsars-have led to much more contentious allegations of oversight. In the first, Selman Waksman and Albert Schatz fought bitterly over whether Dr. Waksman unjustly got the prize alone. In the second, Antony Hewish got the prize but his student, Jocelyn Bell Burnell, did not.

In the DNA story, there has long been a movement to rescue the reputation of Rosalind Franklin, who suffered from the typical sexism of the 1950s and died too soon to win the Nobel Prize. The role played by Dr. Franklin's data was certainly underplayed in most early accounts, but her rehabilitation has ironically obscured somewhat the fact that Dr. Gosling deserves a lot more credit than he generally gets for collecting those data.

When I put this to Dr. Gosling, he deflected me by saying that John Randall, the head of the lab where he, Dr. Wilkins and Dr. Franklin all worked, never gets enough credit for gambling early that DNA was as important as protein and that its structure might yield to attack. Self-effacing as ever, he was quick to remind me that science always requires a broad collaboration: Many people build the arch, even if the person who places the keystone gets most of the credit.

The chief medical ambition of those who study stem cells has always been that the cells would be used to repair and regenerate damaged tissue. That's still a long way off, despite rapid progress exemplified by the presentation of the Nobel Prize next week to Shinya Yamanaka of Kyoto University for a key stem-cell breakthrough. But there's another, less well known application of stem cells that is already delivering results: disease modeling.

Dr. Yamanaka used a retrovirus to insert four genes into a mouse cell to return it to a "pluripotent" state-capable of turning into almost any kind of cell. Last month a team at Johns Hopkins University and the Sloan-Kettering Institute for Cancer Research, using a version of Dr. Yamanaka's technique, successfully grew nerve cells from a patient suffering from a rare disease called Riley-Day syndrome, which is linked to early mortality, seizures and other symptoms and caused by a fault in one gene.

But the purpose was not to put these cells back into the patient. Instead the scientists tested 6,912 chemical compounds on the cells to see if they could find one that "rescued" the "expression" of the gene: that is to say, caused it to produce the protein it is supposed to produce. One of the compounds worked, inducing the gene to be actively transcribed by the cell.

In the not-very-distant future, when something is going wrong in one of your organs, one treatment may be to create some stem cells from your body in the laboratory, turn them into cells of that organ, or even rudimentary structures, and then subject them to experimental treatments to see if something cures the problem. The goal of personalized medicine, in other words, may be reached by stem-cell researchers before it's reached by geneticists.

Further breakthroughs are coming thick and fast to bring that goal closer. Just last week a team largely from Cambridge University announced that they had grown abundant stem cells from particular kinds of blood cells. Amer Rana and his colleagues isolated "late outgrowth endothelial progenitor cells" from patients' blood and then induced them to become stem cells, from which they will be able to grow blood vessels. The first use will be to test drugs on those vessels.

The advantage of these blood-derived stem cells, compared with those derived from skin cells, is that they can be generated in stable form in quantities that allow multiple drug testing. Dr. Rana's team induced stem cells from both healthy people and those with various kinds of a disorder known as pulmonary arterial hypertension. Studying the differences and testing treatments comes next.

Until Dr. Yamanaka's breakthrough of five years ago, few biologists held out much hope that the cells of an adult person could be made into stem cells, in contrast to those of an embryo. Debate still continues among biologists about whether such adult cells approach the gold standard of adaptability that embryonic stem cells show, but few would now bet against that goal being achieved one day.

It's not far-fetched to conclude that, thanks to induced pluripotent stem cells, the embryonic stem-cell debate is fading fast into history. If stem cells derived from the patient's own blood are to offer the same therapeutic benefits as embryonic stem cells, without the immunological complication of coming from another individual, then there would be no need to use cells derived from embryos.

Indeed, that was one of Dr. Yamanaka's original motivations when he set out to induce pluripotency in adult cells. Though he supported embryonic stem-cell research in principle, he once said: "I thought, we can't keep destroying embryos for our research. There must be another way."

I have an op-ed in the Daily Telegraph on the economics of shale gas in Britain:

As part of today's Autumn Statement, George Osborne is expected to approve the building of 30 gas-fired power stations, simplify the regulatory process for fracking and provide tax breaks for shale gas production in Lancashire as early as next year. This is good news for Lancashire, for the British economy, for manufacturing firms and for the global environment. To do anything else would risk economic self-harm.

And if cutting carbon emissions is what floats your boat, you will like shale gas even more. The advent of cheap gas, by displacing coal from electricity generation, has drastically cut America's carbon dioxide emissions back to levels last seen in the early 1990s; per capita emissions are now lower than in the 1960s. (See charts here and here.) Britain's subsidised dash for renewable energy has had no such result: wind power is still making a trivial contribution to total energy use (0.4 per cent) while most renewable energy comes from wood, the highest-carbon fuel of all.

My latest Mind and Matter column in the Wall Street Journal is on yawning:

Even as scientists get better at finding explanations for animal behavior-at the genetic, physiological, evolutionary and neural level-certain habits remain implacably mysterious. And this is true even when we're the species in question and can see the behavior from the inside. Yawning, for instance: You might think that we would know why we yawn, but it has no obvious need, function or effect.

A recent study confirmed that babies who open their mouths in the womb are indeed yawning, not just gaping. This was long suspected and may help to nail shut the coffin of a theory that has refused to die: that yawning is about filling the lungs with oxygen or emptying them of carbon dioxide.

It's now 25 years since Dr. Robert Provine, now at the University of Maryland, did the obvious experiment. He enriched the oxygen or the carbon dioxide in the air breathed by experimental subjects and found not a hint of suppression or exacerbation of yawning compared with control subjects breathing normal air.

So what is known about yawning? Dr. Provine-who is a champion of what he calls "sidewalk neuroscience," experiments anybody can do at home without special equipment-has spent years teasing out the details of yawning, as recounted in his recent book "Curious Behavior: Yawning, Laughing, Hiccupping and Beyond." By asking people to pinch their noses or grit their teeth while yawning he found that "the motor program…will not run to completion" unless you can inhale through your mouth and gape your jaw wide.

Experiments by Andrew Gallup at Princeton University, his father Gordon Gallup and a colleague found that yawning is suppressed by a cool pack strapped to the forehead or by summer temperatures that are higher then body temperature, and that therefore the purpose of yawning may be to cool the brain by inhaling air. But then why do fetuses yawn and why does the need to yawn not get satiated? Having yawned, you often yawn again; it comes in bouts.

Folklore is correct that yawning is triggered by boredom, drowsiness, stretching or other people yawning. Yawning is so contagious and suggestible that even reading an article about it can trigger the reflex, though the contagion is unconscious: It isn't easy to yawn to order. Nor is such contagion confined to human beings; it has been found in baboons, perhaps, and chimpanzees, for sure.

If yawning is empathetic, Matthew Campbell and Frans de Waal of Emory University in Atlanta predicted that chimpanzees would catch yawning from their "in-group" friends but not from "out-group" strangers. Sure enough, 23 chimps yawned more while watching videos of their in-group yawning than when watching videos of strange apes yawning (or familiar apes not yawning).

Yawning can be triggered by the hormone oxytocin-which is released in the brain during empathetic actions like touching, kissing or cooperating, and which triggers a release of dopamine, a feel-good neurochemical. Fabrizio Sanna and colleagues at the University of Cagliari in Italy injected oxytocin into particular parts of the brains of rats and induced yawning, or blocked the effect by injecting an oxytocin-blocking chemical first.

But this is where introspection lets us down. Contagious yawning doesn't feel much like collaborative social bonding; it just feels like involuntary emulation with little emotional baggage. Nor does empathy suggest a physiological "reason" for yawning (after all, we yawn when alone), though Dr. Provine thinks that it may be "a response to and facilitator of change in behavioral or physiological state," maybe synchronizing a group of people about to embark on a behavioral transition. There's a persistent anecdote that parachutists yawn just before jumping out of airplanes.

Perhaps the main purpose of yawning is to remind us how mysterious human beings still are, even to themselves.

You don't need a physics degree to ride a bicycle. Nor, Nassim Nicholas Taleb realized one day, do traders need to understand the mathematical theorems of options trading to trade options. Instead traders discover "heuristics," or rules of thumb, by trial and error. These are then formalized by academics into theorems and taught to new generations of traders, who become slaves to theory, ignore their own common sense and end by blowing up the system. In a neat echo of its own thesis, Mr. Taleb's paper making this point sat unpublished for seven years while academic reviewers tried to alter it to fit their prejudices.

Mr. Taleb, a former trader and expert on probability, tells this story in "Antifragile: Things That Gain from Disorder" to illustrate the point that "we don't put theories into practice. We create theories out of practice." It is a startling insight, which he applies not just to finance but to medicine, science and philosophy. Successful medicine was a "craft built around experience-driven heuristics" that had to fight against entrenched, top-down theorizing from Galen and other wise fools.

Discovery is a trial and error process, what the French molecular biologist François Jacob called bricolage. From the textile machinery of the industrial revolution to the discovery of many pharmaceutical drugs, it was tinkering and evolutionary serendipity we have to thank, not design from first principles. Mr. Taleb systematically demolishes what he cheekily calls the "Soviet-Harvard" notion that birds fly because we lecture them how to-that is to say, that theories of how society works are necessary for society to work. Planning is inherently biased toward delay, complication and inflexibility, which is why companies falter when they get big enough to employ planners.

If trial and error is creative, then we should treat ruined entrepreneurs with the reverence that we reserve for fallen soldiers, Mr. Taleb thinks. The reason that restaurants are competitive is that they are constantly failing. A law that bailed out failing restaurants would result in disastrously dull food. The economic parallel hardly needs spelling out.

The author is a self-taught philosopher steeped in the stories and ideas of ancient Greece (a civilization founded, of course, by traders like Mr. Taleb from Lebanon, as Phoenicia is now known). Anti-intellectual books aren't often adorned by sentences like: "I have been trying to bring alive the ideas of Aenesidemus of Knossos, Antiochus of Laodicea, Menodotus of Nicomedia, Herodotus of Tarsus, and of course Sextus Empiricus." So he takes his discovery-that knowledge and progress are bottom-up phenomena-and derives an abstract theory from it: anti-fragility.

Biological evolution, too, is anti-fragile. The death of unfit individuals is what causes a species to adapt and improve. The body is anti-fragile: Without stress it weakens. To build muscles, you must push them to the point of failure. Though he has no truck with homeopathy, Mr. Taleb is intrigued by hormesis, an old idea, now enjoying a revival, that a small dose of a harmful substance is actually beneficial.

It follows that, in Mr. Taleb's world, the greatest sin is to be a "fragilista," somebody who encourages an institution to become fragile. This word is defined in the book's glossary thus: "somebody who causes fragility because he thinks he understands what's going on. See Iatrogenics." The latter term is from medicine, meaning when doctors do more harm than good, for example, by bleeding the patient in the past, or by putting ice on swellings today.

The Federal Reserve, in Mr. Taleb's view, is an iatrogenic institution run by fragilistas doing more harm than good by trying to root out randomness. This might seem a cheap shot were it not for Mr. Taleb's track record in spotting some of the ingredients of the recent financial crisis. In particular, after 2003, he took a lot of criticism because "I kept telling everybody who would listen to me, including random taxi drivers (well almost), that the company Fannie Mae was sitting on a 'barrel of dynamite.'" He has little mercy for the Keynesian economist Joseph Stiglitz and the Orszag brothers, Peter and Jonathan, economic consiglieres to Democratic administrations, who insisted around the same time that the probability of default in the government-sponsored enterprises was "so small that it is difficult to detect."

As this illustrates, Mr. Taleb doesn't suffer fools, a category in which he includes virtually the entire profession of economics and many other academics. Consider the definition of "touristification," from his glossary: "the attempt to suck randomness out of life. Applies to soccer moms, Washington civil servants, strategic planners, social engineers, 'nudge' manipulators, etc." The opposite, strategy, which he approves, is to embrace "optionality"-like a traveler without an itinerary feeding off randomness by grabbing opportunities as they arise. The author's heroes, from Thales of Miletus, the first Western philosopher, to his intuitive street-wise trader friend Fat Tony, are people who find out how to do things empirically.

There are a few places in the book where I thought Mr. Taleb went wrong-for instance, he seems to underplay the degree to which unnatural medicine, while occasionally doing harm, also greatly prolongs healthy life; and he doesn't notice that climate models deserve as much of his scorn as economic ones. Sometimes he is led astray by his contrarianism, but then that is his point: If you don't take risks, you don't get results.

This is a bold, entertaining, clever book, richly crammed with insights, stories, fine phrases and intriguing asides. Does it achieve its goal, or does it cram and twist the world on to a Procrustean bed of one theory, thereby somewhat contradicting its own empirical and pragmatic outlook? I am not sure. I will have to read it again. And again.

Mr. Ridley writes the Journal's Mind & Matter column.

When an IBM computer program called Deep Blue defeated Garry Kasparov at chess in 1997, wise folk opined that since chess was just a game of logic, this was neither significant nor surprising. Mastering the subtleties of human language, including similes, puns and humor, would remain far beyond the reach of a computer.

Last year another IBM program, Watson, triumphed at just these challenges by winning "Jeopardy!" (Sample achievement: Watson worked out that a long, tiresome speech delivered by a frothy pie topping was a "meringue harangue.") So is it time to take seriously the prospect of artificial intelligence emulating human abilities?

Yes, argues the inventor and futurist Ray Kurzweil in his new book "How to Create a Mind." Mr. Kurzweil reckons that a full understanding and simulation of the human brain is a lot closer than most people think. Since he has a more impressive track record of predicting technological progress than most, he deserves to be heard.

It's become fashionable to think of the brain as so intricate as to be almost beyond even theoretical comprehension. For example, Paul Allen, the Microsoft co-founder, criticized both IBM's Watson and Mr. Kurzweil in a recent article, claiming that the former's knowledge was brittle and domain-specific, while the latter failed to understand that every structure in the brain "has been precisely shaped by…evolution to do a particular thing." Mr. Allen posits a "complexity brake" that would necessarily limit the understanding and replication of the brain.

Mr. Kurzweil's reply in his book is persuasive. For a start, the brain is built from a relatively small and simple body of information-the 25 million bytes of the genome. The complexity comes from ordered growth and elaboration. Second, the brain contains massive redundancy, with certain kinds of basic pattern-recognizing circuits repeated maybe 300 million times in different brain regions. Third, as Van Wedeen of Harvard Medical School and colleagues found in a recent study, much of the brain has a horizontal grid of fibers running at right angles, connecting vertically: a bit like the streets and elevators of Manhattan.

Moreover, the design of artificial intelligence systems has been converging with the way brains developed. Using evolutionary algorithms (a fancy form of trial and error), Mr. Kurzweil himself developed some of the successful speech-recognition software that we all take for granted.

Mr. Kurzweil agrees with another innovator turned neuroscientist, Jeff Hawkins (the PalmPilot's inventor), in believing that the human brain is basically a set of prediction machines that work by forecasting how a pattern of perceptions will develop. As we put together the pieces of, say, a visual image, information is flowing up (by the neural grid's elevators) from basic pattern recognizers to higher and more abstract integrations, but also back down from the higher levels predicting what patterns will be found in missing parts of the image or as an image changes. Failed predictions-"surprises"-may be passed (via the neural grid's streets) to higher levels in the neural hierarchy for conscious resolution.

If this picture is broadly right, then replicating a brain isn't impossible. Engineers trying to reduce circuitry features to five microns once scoffed at ever reaching one micron, while today they're at 0.022 microns. So, says Mr. Kurzweil, the neuro-pessimists will be wrong because "the project to reverse-engineer the human brain is making similar progress."

Moreover, says Mr. Kurzweil, the brain is an essentially linear organ, sequentially processing information, which may be why we find it so hard to comprehend the nonlinear trends that so dominate the progress of technology. With both hardware and software changing exponentially, it would be foolish, not wise, to bet against the emulation of the human brain in silicon within a couple of decades.

Evolution by sexual selection is an idea that goes back to Charles Darwin. He had little doubt that it explained much about human beings, and modern biologists generally agree. One of them has even put a figure on it, concluding that some 54.8% of selection in human beings is effectively caused by reproduction of the sexiest rather than survival of the fittest.

Some years ago, the evolutionary psychologist Geoffrey Miller in his book "The Mating Mind" explored the notion that since human males woo their mates with art, poetry, music and humor, as well as with brawn, much of the expansion of our brain may have been sexually selected.

Psychological evidence points the same way. In one experiment, men who were shown pictures of women promptly expressed more extravagant desires for expensive luxuries, whereas women showed no such effect after seeing pictures of men. There's historical evidence, too. As Aristotle Onassis is supposed to have said, "If women did not exist, all the money in the world would have no meaning."

Moreover, Michael Shermer, in his book "The Mind of the Market," argues that you can trace anticapitalist egalitarianism to sexual selection. Back in the hunter-gatherer Paleolithic, inequality had reproductive consequences. The successful hunter, providing valuable protein for females, got a lot more mating opportunities than the unsuccessful. So it's possible that men still walk around with a relatively simple equation in their brains, namely that relative success at obtaining assets results in more sexual adventures and more grandchildren.

If so, this might explain why it is relative, rather than absolute, inequality that matters so much to people today. In modern Western society, when even relatively poor people have access to transport, refrigeration, entertainment, shoes and plentiful food, you might expect that inequality would be less resented than a century ago-when none of those things might come within the reach of a poor person. What does it matter if there are people who can afford private jets and designer dresses?

But clearly that isn't how people think. They resent inequality in luxuries just as much if not more than inequality in necessities. They dislike (and envy) conspicuous consumption, even if it impinges on them not at all. What hurts is not that somebody is rich, but that he is richer.

This is a classic statement of sexual selection. It isn't the peacock with the big-enough tail that gets to mate; it's the peacock with the biggest tail. If this sounds old-fashioned in an age of working women, gender equality and relative sexual continence, then open your eyes and look around you: The man with the most money or power still gets more sexual opportunities than the man with the least. Ask David Petraeus.

In human beings, females compete for males as well as vice versa. In many species, sexual selection is a force that acts on only one sex, usually the male. Peahens, which can share the best males and don't require them to be diligent parents after mating, do not grow colorful tails. But in other species, notably some seabirds and parrots, where males and females share parenting duties equally, both sexes are equally colorful-a result of competition by both sexes to attract the best mates.

Never has an undercover video sting delighted its victims more. A Greenpeace investigation has caught some Tory MPs scheming to save the countryside from wind farms and cut ordinary people's energy bills while Lib Dems, Guardian writers and Greenpeace activists defend subsidies for fat-cat capitalists and rich landowners with their snouts in the wind-farm trough. Said Tories will be inundated with fan mail.

Yet, for all the furore wind power generates, the bald truth is that it is an irrelevance. Its contribution to cutting carbon dioxide emissions is at best a statistical asterisk. As Professor Gordon Hughes, of the University of Edinburgh, has shown, if wind ever does make a significant contribution to energy capacity its intermittent nature would require a wasteful "spinning" back-up of gas-fired power stations, so it would still make no difference to emissions or might make them worse.

And wind is not the worst of the renewables. By far the largest source of renewable energy is bio-energy (ie vegetable matter turned into solid, liquid or gaseous fuel), which is expanding fast and doing less than nothing to cut emissions. Even the big three green multinationals - Greenpeace, Friends of the Earth and WWF - have come out against biofuels.

Last year, despite a decade of subsidies and the desecration of quite a bit of countryside, 96.8 per cent of our total energy still came from fossil fuels and nuclear. The rest came from bio-energy (2.6 per cent), leaving a derisory 0.6 per cent from wind, hydro, solar, wave, tidal and geothermal put together. It is therefore a little-known fact that 77 per cent of Britain's renewable energy involves burning something. (All these figures for 2011 are from the Department of Energy).

And there is nothing carbon-saving about bio-energy. Take wood, a more carbon-rich fuel even than coal. As the environmental scientist Jesse Ausubel, of Rockefeller University in New York, has shown, when you burn wood more carbon dioxide is emitted than from coal for the same amount of energy.

Yet Britain is dashing to replace coal with wood. Many coal plants are being subsidised to switch to biomass. Drax in North Yorkshire, the country's largest power station, is switching partly from coal to biomass while Eggborough, in the same county, will convert fully to become Britain's leading renewable power plant.

By 2030, according to current plans, the UK will be burning five times the maximum timber harvest that Britain could conceivably produce. So most of it will be - and already is being - imported in the form of pellets, lumber, olive pips and peanut husks. Some will come from tropical rain forests, or will raise prices enough to encourage the felling of more rain forests.(Remember, it is fossil fuels we have to thank for reversing the great deforestation of these islands in the Middle Ages - Britain now has three times as much forest as in the 1800s.)

Although today's dash back to biomass is driven by European carbon-emissions reduction targets, not an ounce of carbon will be saved. Its champions argue that because trees grow in place of those chopped down, wood is almost carbon-neutral, whereas fossil fuels are not. But, as Professor Helmut Haberl, of the University of Klagenfurt in Austria, has pointed out, this makes no sense. Carbon is carbon. Land grows plants whether it is used for biofuel or not. Chopping down a tree to burn its wood oxidises the tree's carbon atoms decades before they would be released by decay. It could take 200 years to break even in carbon terms by planting new trees.

So it is a ludicrous myth that biomass cuts carbon emissions.

Of course, the biomass dash is excellent news for woodland owners (such as me) who are now incentivised to thin and fell woodlands at a faster rate in the hope of making, or more likely losing less, money on the management of woods. It is less good news for the coal industry, in which I also have an indirect interest. But it's the least fun for those of us who pay electricity bills, where the subsidy is artfully concealed.

The Renewable Heat Initiative, encouraging us to heat our homes at public expense with wood rather than gas, is even worse. Wood is much higher in carbon than gas, so if you switch from gas heating to wood you generate more CO2 emissions; not to mention depriving beetles of rotting logs and woodpeckers of beetles. Lorries will soon be delivering 25,000 tonnes of wood chips a year to Heathrow's Terminal 2. Compared with gas, this is madness in economic, ecological and traffic terms.

Growing crops to be turned into biofuel makes even less sense. For a start, the diesel and fertiliser come from fossil fuels, so some of the world's biofuel crops are not carbon neutral when harvested, let alone when burnt. Those that are, such as Brazilian sugar-cane ethanol, rely on cheap labour. But it's worse than that. Biofuels are displacing food crops, which raises prices and in turn encourages forest clearance to grow more crops. A Leicester University study found that such "indirect land use changes" might take 423 years to pay back the up-front carbon debt.

Copying Germany, Britain's farmers are now being enticed by subsidies to install anaerobic digesters. Contrary to popular myth these digest, not manure, but raw crops, mainly maize. Again this makes no sense.

Britain's dash for renewable energy is already costing its hard-pressed economy tens of billions of pounds a year - and rising. Yet it will not make a dent in carbon dioxide emissions, let alone enough to affect climate.

Meanwhile, across the Atlantic, huge cuts in carbon dioxide emissions are happening. America is now producing less CO2 than it did in the early 1990s, and 30 per cent less per head than it did in in 1973. It has done this while cutting rather than raising energy bills and generating revenues rather than consuming subsidies. The reason? Cheap gas replacing coal, thanks to fracking. If you are worried about carbon dioxide, why not choose a technology that works rather than one that doesn't?

My latest Mind and Matter column in the Wall Street Journal is on the Medieval Warm Period:

A flurry of recent scientific papers has tried to measure the warmth of the "Medieval Warm Period" (MWP) of about 1,000 years ago. Scientists have long debated whether it was cooler or warmer than today, and whether the warmth was global or regional. The point for nonscientists: If recent warming has precedents, some might find it less alarming.

Until the late 1990s, researchers generally agreed that the MWP was warmer than today and that the "Little Ice Age" of 1500-1800 was colder. Then in 2001 the Intergovernmental Panel on Climate Change adopted the "hockey stick" graph devised by Michael Mann at the University of Virginia and colleagues.

Using temperature indicators such as tree rings and lake sediments, the graph rewrote history by showing little warmth in the 11th century and little cold in the 17th, but a sharp spike in late-20th-century temperatures. That graph helped to persuade many people (such as me) that recent temperature rises were unprecedented in scale and speed in at least 1,400 years.

But critics of the graph pointed out that it used a statistical technique that overemphasized hockey-stick shaped data from unreliable indicators, such as tree rings in bristlecone pine trees and Scandinavian lake sediments influenced by 20th-century land-use changes. Four recent studies have now rehabilitated the MWP as a period of unusual warmth, though they disagree on whether it was as warm or warmer than today.

Jan Esper of the University of Mainz and his colleagues looked at pine wood densities from Sweden and Finland and found "evidence for substantial warmth during Roman and medieval times, larger in extent and longer in duration than 20th-century warmth." Bo Christiansen of the Danish Meteorological Institute and Fredrik Ljungqvist of Stockholm University looked at 32 indicators across the Northern Hemisphere and found the level of warmth during the peak of the MWP "in the second half of the 10th century equaling or slightly exceeding the mid-20th century warming."

Thomas Melvin of the University of East Anglia and colleagues reanalyzed one of the tree samples from Sweden used in the "hockey stick" and concluded: "We can infer the existence of generally warm summers in the 10th and 11th centuries, similar to the level of those in the 20th century."

A fourth study of creatures called diatoms in Chinese lake sediments found that the period "between ca. A.D. 1150 and 1200 was the warmest interval of the past 1,000 years."

Taken together, these studies cast doubt on the IPCC's conclusion in 2007 that "the evidence is not sufficient to support a conclusion that [Northern] hemispheric mean temperatures were as warm, or the extent of warm regions as expansive, as those in the 20th century as a whole, during any period in medieval times."

But was the medieval warm period confined to the Northern Hemisphere?

I consulted a database of papers collated by the climate-skeptic website CO2Science.org, run by the Center for the Study of Carbon Dioxide and Global Change, a nonprofit research center in Tempe, Ariz. The database contains numerous published studies of isotopes and other indicators in caves, lake sediments and other samples from Chile, New Zealand, South Africa and Antarctica that find the MWP warmer than today. Two Antarctic studies, for instance, concluded that current warming "is not yet as extreme in nature as the MWP" and that "the present state of reduced ice on the western Antarctic Peninsula is not unprecedented." A far smaller number of studies, such as one from Lake Tanganyika, found the MWP cooler than today.

It remains possible that today's warming is different from that of the Middle Ages. For example, while summers might have been warmer then, winters might be warmer today (if today's warming is caused by carbon dioxide, that should be true). And of course, it is the future, not the past, that scientists expect to be dangerous. Nonetheless, the evidence increasingly vindicates the scientists who first discovered the Medieval Warm Period.

Until recently it was possible, even plausible, to think that the faculty of vision had originated several times during the course of animal evolution. New research suggests not: vision arose only once and earlier than expected, before 700 million years ago.

Davide Pisani and colleagues from the National University of Ireland have traced the ancestry of the three kinds of "opsin" protein that animals use, in combination with a pigment, to detect light. By comparing the genome sequences of sponges, jellyfish and other animals, they tracked the origin of opsins back to the common ancestor of all animals except sponges, but including a flat, shapeless thing called a placozoan. Some time after 755 million years ago, the common ancestor of ourselves and the placozoa duplicated a gene and changed one of the copies into a recognizable opsin.

Placozoans still have just that one kind of opsin, and it lacks the key amino acid change at position 296 that makes light detection possible, so Dr. Pisani concludes that the last opsin common ancestor, dubbed LOCA, had no vision. But on the other branch, the common ancestor of ourselves, insects and jellyfish made the change to light detection, then experienced two more duplications some time between 711 million and 700 million years ago to give the three kinds of light-sensing opsins we still possess today.

That vision was a single evolutionary innovation is a discovery that would have surprised an earlier generation of evolutionary biologists, who contrasted the compound eye of the insect with the camera-like eye of human beings and imagined several parallel inventions. But some years ago it emerged that the very same gene, called Pax6, commands the development of the insect eye and the human eye, hinting at a common origin. Still more surprising, a version of a Pax gene was then found directing the development of simple eyes in jellyfish. So the single origin of vision has become gradually more plausible.

All this would come as a relief to Charles Darwin, who worried about eyes, because their perfect complexity seemed to defy gradual evolutionary assembly: What use is half an eye? In 1860 he wrote to the American botanist Asa Gray: "The eye to this day gives me a cold shudder, but when I think of the fine known gradation my reason tells me I ought to conquer the odd shudder." In fact, the anatomy of eyes shows every gradation between simple light-sensitive spots and full cameras. The detailed genetic evidence of descent with modification from a single common ancestor further vindicates Darwin and has largely silenced the Intelligent Design movement's use of the eye as a favored redoubt.

After the duplications that led to working opsin molecules, there seems to have been a long pause before complex eyes appeared.

The first lensed eyes that fossilized belonged to the trilobites which dominated the Cambrian oceans after 525 million years ago. Andrew Parker of Oxford University argued in a book a few years ago that newly perfected eyes explain the sudden appearance of many kinds of hard-bodied animals, the so-called Cambrian explosion. With predators hunting by sight for the first time, prey needed protection and mobility, so an arms race led to a plethora of new hard-body designs.

Just as eyes suddenly enabled our ancestors to see the world around them, so the capacity to read genomes enables us to see deep into the past. Long before LOCA there lived a creature called LUCA, the last universal common ancestor. It was only about 50 years ago that the unity of life became apparent for the first time. The molecular biologist Francis Crick, surveying the experiments that were deciphering the genetic code in bacteria, animals and yeast cells, and seeing that they were all converging on the same universal cipher, concluded that there is only one kind of life on the planet: that plants, animals and microbes must once have shared a common ancestor.

I'm pessimistic about the ash trees. It seems unlikely that a fungus that killed 90 per cent of Denmark's trees and spreads by air will not be devastating here, too. There is a glimmer of hope in the fact that ash, unlike elms, reproduce sexually so they are not clones - uniformly vulnerable to the pathogen. But it's only a glimmer: tree parasites, from chestnut blight to pine beauty moth, have a habit of sweeping through species pretty rampantly, because trees are so long-lived they cannot evolve resistance in time.

The Forestry Commission's apologists are pleading 'cuts' as an excuse for its failure to do anything more timely to get ahead of the threat, but as a woodland owner I am not convinced. An organisation that has the time and the budget to pore over my every felling or planting application in triplicate and come back with fussy and bossy comments could surely spare a smidgen of interest in looming threats from continental fungi that have been spreading out from Poland for 20 years. The commission was warned four years ago of the problem.

Here's what the commission was up to instead. Just last year, I received a letter from the Forestry Commission demanding access to survey one of my woods to answer the question 'what are the forecasts for timber, biomass and carbon?' in order to 'help the United Kingdom meet international commitments, such as reporting for the Global Forest Resources Assessment and the Ministerial Conference on the Protection of Forests in Europe (MCPFE)'.

Notice the Sir Humphrey-esque circular argument: surveys must be done so that the results can be reported to assessment meetings. In other words, as far as I can tell, the Forestry Commission's priority has been, as in so many government bodies, to supply talking points for the international carbon-obsessed bureaucracy. The implicit assumption here, of course, is that climate change is the greatest threat to Britain's trees, when in reality far greater threats come from diseases carried around by foresters themselves.

This is happening throughout the world of nature conservation. A climate fetish has sucked all the oxygen from the real threats to species and habitats - indeed it has actually begun to make those threats worse. Remember, climate change has extinguished no species in modern times, not one. For a while the scientists thought they had one - the golden toad of Costa Rica, supposedly extinguished by the loss of cloud to moisten its cloud-forest habitat. Climate alarmists like Tim Flannery made much of this pitiful and beautiful harbinger in their books.

But the awkward fact was that the temperature had not changed in Costa Rica. The forests were drier, true, but only because so many of the trees had been cut down on the lower slopes of the mountains. And in any case, the golden toad actually succumbed, like so many other amphibians, to a fungus brought in perhaps on the boots of conservationists. I have lived long enough to see the great amphibian decline blamed on acid rain, ozone depletion, climate change and all sorts of other red herrings. Those in the know now admit that the true culprit was probably the international laboratory trade in African clawed toads carrying a chytrid fungus. Was that conclusion delayed by the other obsessions? I think so.

As an ardent champion of free trade, by the way, I make one exception: we are far too free in trading live creatures that can carry diseases or smuggled pests. We need to get more serious about this issue.

Instead, the perpetual urge to elevate climate change as an ecological threat has distracted the world from the truth that the greatest cause of species extinction is the invasion of alien exotic species: fungi, weeds, snakes, rats, cats, goats, mink, grey squirrels. No other cause even comes close to this one. Of the 181 species of bird and mammal that have died out since 1500, just nine were on continents. The rest were on islands (Australia counts as an island in this respect, having an isolated and vulnerable fauna).

Island animals and plants are far more vulnerable to introduced predators, parasites and competitors than continental species, but even on continents invasive aliens are the biggest problem: in the British countryside, mink, grey squirrels, Spanish bluebells, Himalayan balsam, Japanese knotweed. Every chance I get I tell wildlife charities: if you want a donation from me, shut up about carbon and speak up about invasive aliens. But government effectively tells them the opposite, so they smile politely at me as if I was mad.

The Forestry Commission's comparative neglect of ash bio-security as it flits off to MCPFE meetings about carbon is emblematic of the entire problem. Indeed, the Forestry Commission was until very recently urging and bribing us to bring exotic aliens into the countryside: sitka spruce and lodgepole pine were their idea. The latter was a commercial disaster as well as useless for red squirrels and crossbills. It is a startling fact that in the 20th century, ancient semi-natural woodland in public hands had a higher probability of being felled and replanted as regiments of sitka than if it was in private hands.

The carbon fetish is not just distracting us from real conservation problems; it is actually making some worse. In the name of supposedly fixing the climate at some imaginary equilibrium, we are dashing for biomass. On current plans, by 2020 Britain will be burning 60 million tonnes of wood in power stations, 10 per cent of our transport fuel will be biofuel and large areas of the countryside will be producing crops of anaerobic digesters to make gas for electricity.

Much of this biomass will be imported. The land required to grow it will not be available to grow food, which will be displaced on to other land cleared from forests, which as the University of Leicester found in a recent study will 'actually increase emissions relative to petroleum fuels'. So we will be increasing our dependence on imports, driving up energy bills, driving up food prices for the world's poor, cutting down precious rain forests and increasing carbon emissions. Quintuple whammy: good work, lads.

The return of the wolf is one of the unexpected ecological bonuses of the modern era. So numerous are wolves that this fall Wisconsin and Wyoming have joined Idaho and Montana in opening wolf-hunting seasons for the first time in years. Minnesota follows suit next month; Michigan may do so next year. The reintroduced wolves of Yellowstone National Park have expanded to meet the expanding packs of Canada and northern Montana.

The same is happening in Europe. Wolf populations are rising in Spain, Italy and Eastern Europe, while in recent years wolves have recolonized France, Germany, Sweden and Norway, and have even been seen in Belgium and the Netherlands. Nor are wolves the only "apex predators" to boom in this way. In the U.S., bears and mountain lions are spreading, to joggers' dismay. Coyotes are reappearing even within cities like Chicago and Denver.

The effect of top predators on lesser predators, like foxes, raccoons and skunks, not to mention domestic cats, can be devastating. Wolves may kill deer and cows, but they also kill these smaller "mesopredators"-middle-of-the-food-chain carnivores. That may be good news for other creatures, especially birds. The very presence of large predators can intimidate the mesopredators: In the Bahamas, large groupers cause small ones to spend more time in hiding, allowing smaller reef fish to thrive.

In 1988 ecologists coined the term "mesopredator release" for the theory that the original disappearance of apex predators at the hand of human beings had caused a population boom in small opportunistic predators and omnivores. In Africa, for instance, baboons have boomed where leopards have been exterminated, to the detriment of antelopes as well as crops. In one marine case, overharvesting of Atlantic sharks caused an expansion in the number of rays, which in turn hurt the stocks of scallops.

Now, as exemplified by the wolf, top predators are returning little by little. This is due to legal protection and the increasing retreat of people to cities and suburbs (teenagers who play computer games would once have staked out wolf kills to protect the family's herd).

So is the return of top predators now suppressing rather than releasing mesopredators?

In parts of Europe, introduced American mink have harmed birds, water voles and other waterside wildlife. But now newly abundant predators of mink, once devastated by DDT, have caused mink populations to fall. In Finland sea eagles are hunting mink; in Britain otters are.

Complicating the picture, some species can be either apex predators or mesopredators. In Yellowstone National Park, coyotes are mesopredators that appear to have declined at the paws of wolves, which is good news for rodents and other creatures. But in suburbs the coyote is more like an apex predator, whose return lays waste the domestic cats that kill so many birds. Even in rural areas, the coyote is an efficient predator of foxes, skunks and badgers. So the arrival of coyotes in an area may be bad for rabbits but good for birds.

Likewise, raccoons are usually a classic mesopredator, but controlling their numbers in Florida to save turtle eggs from their depredations proved counterproductive, because egg-eating crabs then thrived.

Ecology is a complicated and unpredictable business. To test whether the revival of large predators is generally good news for ecosystems, Dr. Laura Prugh of the University of Alaska at Fairbanks is setting out to compare coyote, fox and lynx populations in an area with intensive wolf control, compared with nearby Denali National Park and Preserve, where wolf populations are intact. As she and her co-writers said in a recent paper, given what programs to control mesopredators cost, letting apex predators thrive may provide an "ecosystem service" by controlling them cheaply and more effectively.

In 1965, the computer expert Gordon Moore published his famous little graph showing that the number of "components per integrated function" on a silicon chip-a measure of computing power-seemed to be doubling every year and a half. He had only five data points, but Moore's Law has settled into an almost iron rule of innovation. Why is it so regular?

The technology guru Ray Kurzweil recently pointed out that a version of Moore's Law has been true since the early years of the 20th century. That is to say, before the integrated circuit even existed, the four previous technologies-electromechanical, relay, vacuum tube and transistor-had all improved along the very same trajectory: The computing power that $1,000 buys has doubled every two years for a century.

A similar graph can be plotted for the number of radio communications fitting into the electromagnetic spectrum. Ever since Guglielmo Marconi's first transmission in 1895, the number of possible simultaneous wireless communications has doubled every 30 months. (This is now known as Cooper's Law, after the inventor Martin Cooper, who demonstrated the first hand-held cellphone.)

Both graphs are roughly exponential, meaning that they curve rapidly upward (or appear as straight lines if plotted on a logarithmic scale). Why don't they move in lurches followed by stagnations? And why can't we cheat these laws by jumping ahead?

What's remarkable about the extension of these regularities back in time is that they now appear to have marched imperturbably through the upheavals of the 20th century without breaking step. How is it possible that the Great Depression did not slow down technological progress? Why didn't the great infusion of technology spending during World War II accelerate it?

There's no certain answer. The inevitable, inexorable and incremental march of technological improvement remains baffling, as does the steady march of world economic growth at 2% to 5% a year ever since the 1940s-far steadier than the progress of any individual country.

A glimmer of explanation can be found in Reed's Law, named after the computer scientist David P. Reed. This states that the utility of large networks increases exponentially with the size of the network. That is to say, it goes up faster than the number of participants or the number of possible pairs of participants (which goes up by Metcalfe's Law).

The Silicon Valley investor Steve Jurvetson thinks this may explain the exponential shape of Moore's and Cooper's laws-so long as you substitute "ideas" for participants. In other words, technology is driving its own progress by steadily expanding its own capacity to bring ideas together. The implication is that, short of arresting half the planet's people, we could not stop the march of technology even if we wanted to.

This is mainly reassuring, because bad policies can't prevent improvement-but also depressing, because good policies can't accelerate improvement. The policies and breakthroughs to which we attach such importance are all but irrelevant on the global scale, though they can, of course, result in a country missing out on the benefits or losing its natural "share" of technology or growth to another country (ask the North Koreans).

A few years ago Mr. Jurvetson added to this menagerie of laws by coining Rose's Law of quantum computing, after a Canadian executive in the field. (Such computers focus on probabilities and exploit the idea that subatomic particles can exist in multiple states at the same time.) The law's prediction of an annual doubling in quantum computing capacity-at speeds too scary to contemplate-has come to pass. If quantum computers are actually doing anything practical in their incomprehensible brains, then quantum computers will soon make their conventional cousins look primitive.

Yet to most people the word "epigenetics" has come to mean something quite different: the inheritance of nongenetic features acquired by a parent. Most scientists now think the latter effect is rare, unimportant and hugely overhyped.

There are several mechanisms of modifying DNA without altering the genetic code itself. The key point is that these modifications survive the division of cells.

This is crucial to the development of the body: It means brain cells express different genes than kidney cells. Among the implications: a faulty modification in the womb, caused perhaps by maternal dietary deficiency, may condemn the baby to future disease. Babies gestated during the "hunger winter" of 1944-45 in the Netherlands were more likely to be obese and diabetic as adults. Likewise, rat pups insufficiently licked and groomed by their mothers are more likely to be stressed when they grow up.

The far bolder claim is that these modifications can be transmitted between generations, surviving not only the normal division of cells during growth (by "mitosis") but the special processing of cells that prepares them for sexual reproduction as sperm or eggs ("meiosis").

This theory is controversial for three reasons. First, the entire epigenetic mechanism is normally stripped away when an egg or sperm is made. Second, this version of epigenetics rehabilitates the theories of the French scientist Jean-Baptiste Lamarck, who two centuries ago postulated that traits acquired during a lifetime can be genetically passed on to the next generation-a theory long since buried by experiments. Third, the evidence for such a process is sketchy-while the evidence that it has negligible impact, even if it can occasionally happen, is strong.

Caroline Relton of Britain's Newcastle University and George Davey Smith of Bristol University, the editors of a recent special issue of the International Journal of Epidemiology, conclude that epigenetic inheritance may be a distracting wild-goose chase. Yet headlines proclaim "a turning point in our understanding of heredity" and "why your DNA isn't destiny."

The evidence to back up such claims is threadbare. Frequently mentioned is a study of a remote Swedish province called Overkalix, which suffered famines whose effects are felt in the health of the second generation of descendants. But the sample size is small, the effects marginal and no specific epigenetic reprogramming has been established as the cause. Evidence from rats is slightly better: One study found energy metabolism in pregnant rats affected by what happened to the parent. But the most famous animal case, involving a mouse's coat color tied to diabetes and obesity, is somewhat unpredictable and untypical.

Moreover, beginning a century ago with Wilhelm Johannsen, who coined the word "gene," many experiments have ruled out all but the most trivial Lamarckian effects. These now- forgotten tests involved "pure lines" of genetically identical plants or animals. The variation in pure lines, in weight of beans in bean plants for example, again and again shows no heritability, ruling out heritable nongenetic effects.

As Dr. Davey Smith puts it: "The conclusion from over 100 years of research must be that epigenetic inheritance is not a major contributor" to physical resemblance across generations.

Generally, technologies are judged on their net benefits, not on the claim that they are harmless: The good effects of, say, the automobile and aspirin outweigh their dangers. Today, arguably, adopting certain new technologies is harder not just because of a policy of precaution but because of a bias in much of the media against reporting the benefits.

Shale gas is one example, genetically modified food another, where the good news is deemed less newsworthy than the bad. A recent French study claimed that both pesticides and GM corn fed to cancer-susceptible strains of rats produced an increase in tumors. The study has come in for withering criticism from mainstream scientists for its opaque data, small samples, unsatisfactory experimental design and unconventional statistical analysis, yet it has still gained headlines world-wide. (In published responses, the authors have stood by their results.)

The French study contradicts a Japanese paper that used larger samples, longer trials and accepted experimental designs, yet received virtually no notice because it found no increase in cancer in rats fed on GM crops. This is a problem that's bedeviled GM technology from the start: Studies that find harm are shouted from the media rooftops, those that do not are ignored.

So to redress the balance, I thought I'd look up the estimated benefits of genetically modified crops. After 15 years of GM planting, there's ample opportunity-with 17 million farmers on almost 400 million acres in 29 countries on six continents-to count the gains from genetic modification of crop plants. A recent comprehensive report by Graham Brookes and Peter Barfoot for a British firm, PG Economics, gives some rough numbers. (The study was funded by Monsanto, which has major operations in biotech, but the authors say the research was independent of the company and published in two peer-reviewed journals.)

The most obvious benefit is yield increase. In 2010, the report estimates, the world's corn crop was 31 million tons larger and the soybean crop 14 million tons larger than it would have been without the use of biotech crops. The direct effect on farm incomes was an increase of $14 billion, more than half of which went to farmers in developing countries (especially those growing insect-resistant cotton).

In addition, a range of non-pecuniary benefits have been recorded, from savings in fuel, time and machinery to a better health and safety record on the farm (since less pesticide is needed), shorter growing cycles and better quality of product. In India-where the International Service for the Acquisition of Agri-Biotech Applications says 88% of cotton is now genetically modified to resist pests and insecticide use has halved-bee keepers are losing fewer bees.

As this illustrates, the most striking benefits are environmental. The report calculates that a cumulative total of 965 million pounds of pesticide have not been used because of the adoption of GM crops. The biggest impacts are from insect-resistant cotton and herbicide-tolerant maize, both of which need fewer sprayings than their conventional equivalents.

The use of less fuel in farming GM crops results in less carbon-dioxide emission. In addition, herbicide-tolerant GM crops can often be grown with little or no plowing in stubble fields that are sprayed with herbicides. The result is to allow more carbon to remain in the soil, since plowing releases carbon as microbial exhalation. Taken together, Messrs. Brookes and Barfoot estimate, this means that the GM crops grown in 2010 had an effect on carbon-dioxide emissions equivalent to taking 8.6 million cars off the road.

There is a rich irony here. The rapidly growing use of shale gas in the U.S. has also driven down carbon-dioxide emissions by replacing coal in the generation of electricity. U.S. carbon emissions are falling so fast they are now back to levels last seen in the 1990s. So the two technologies most reliably and stridently opposed by the environmental movement-genetic modification and fracking-have been the two technologies that most reliably cut carbon emissions.

An individual's personality shapes his or her political ideology at least as much as circumstances, background and influences. That is the gist of a recent strand of psychological research identified especially with the work of Jonathan Haidt. The baffling (to liberals) fact that a large minority of working-class white people vote for conservative candidates is explained by psychological dispositions that override their narrow economic interests.

In his recent book "The Righteous Mind," Dr. Haidt confronted liberal bafflement and made the case that conservatives are motivated by morality just as liberals are, but also by a larger set of moral "tastes"-loyalty, authority and sanctity, in addition to the liberal tastes for compassion and fairness. Studies show that conservatives are more conscientious and sensitive to disgust but less tolerant of change; liberals are more empathic and open to new experiences.

But ideology does not have to be bipolar. It need not fall on a line from conservative to liberal. In recently published paper, Ravi Iyer from the University of Southern California, together with Dr. Haidt and other researchers at the data-collection platform YourMorals.org, dissect the personalities of those who describe themselves as libertarian.

These are people who often call themselves economically conservative but socially liberal. They like free societies as well as free markets, and they want the government to get out of the bedroom as well as the boardroom. They don't see why, in order to get a small-government president, they have to vote for somebody who is keen on military spending and religion; or to get a tolerant and compassionate society they have to vote for a large and intrusive state.

The study collated the results of 16 personality surveys and experiments completed by nearly 12,000 self-identified libertarians who visited YourMorals.org. The researchers compared the libertarians to tens of thousands of self-identified liberals and conservatives. It was hardly surprising that the team found that libertarians strongly value liberty, especially the "negative liberty" of freedom from interference by others. Given the philosophy of their heroes, from John Locke and John Stuart Mill to Ayn Rand and Ron Paul, it also comes as no surprise that libertarians are also individualistic, stressing the right and the need for people to stand on their own two feet, rather than the duty of others, or government, to care for people.

Perhaps more intriguingly, when libertarians reacted to moral dilemmas and in other tests, they displayed less emotion, less empathy and less disgust than either conservatives or liberals. They appeared to use "cold" calculation to reach utilitarian conclusions about whether (for instance) to save lives by sacrificing fewer lives. They reached correct, rather than intuitive, answers to math and logic problems, and they enjoyed "effortful and thoughtful cognitive tasks" more than others do.

The researchers found that libertarians had the most "masculine" psychological profile, while liberals had the most feminine, and these results held up even when they examined each gender separately, which "may explain why libertarianism appeals to men more than women."

All Americans value liberty, but libertarians seem to value it more. For social conservatives, liberty is often a means to the end of rolling back the welfare state, with its lax morals and redistributive taxation, so liberty can be infringed in the bedroom. For liberals, liberty is a way to extend rights to groups perceived to be oppressed, so liberty can be infringed in the boardroom. But for libertarians, liberty is an end in itself, trumping all other moral values.

Dr. Iyer's conclusion is that libertarians are a distinct species-psychologically as well as politically.

This week probably saw the Arctic Ocean's sea ice reach its minimum extent for the year and begin to expand again, as it usually does in mid-September. Given that the retreat of Arctic ice has become a key piece of evidence for those who take a more alarmed view of global warming, it's newsworthy that 2012's melt was the greatest since records began in 1979, with sea ice in the Northern Hemisphere shrinking to about 1.3 million square miles, or about half the 1979-2008 average.

As this column has sometimes pointed out ways in which the effects of global warming are happening more slowly than predicted, it is fair to record that this rate of decline in Arctic sea ice is faster than many predicted. Although an entirely ice-free Arctic Ocean during at least one week a year is still several decades away at this rate, we are halfway there after just three decades.

Arctic melts on this scale have happened before, however. Svend Funder of the Danish Museum of Natural History and his colleagues recently studied the northern coast of Greenland, where the land-fast sea ice never breaks up, even in a year like this. Yet evidence of wave action in the past (indicating open waters) and waterlogged driftwood show that for 2,500 years in the "Holocene Optimum" period, when Arctic summer temperatures were two to four degrees Celsius warmer than today, the summer melt of the Arctic Ocean routinely left half as much ice as this year. [A quote from Funder's paper: "Multiyear sea ice reached a minimum between ~8500 and 6000 years ago, when the limit of year-round sea ice at the coast of Greenland was located ~1000 kilometers to the north of its present position." hat tip, see here]

Another study, by Jørgen Berge and colleagues from the University Centre in Svalbard, Norway, and other institutions, discovered a downward migration of egg-carrying amphipod crustaceans that enables them to recolonize Arctic ice from ice-free areas using deep currents. They say this implies that some animals are well adapted to the seasonal loss of ice. ["From an evolutionary perspective, this may have been a successful adaptive strategy in a more seasonally ice-covered Arctic, as experienced several times during the past 12,000 years, some reports indicate that the Arctic Ocean was void of summer sea ice as late as 8000 years ago."]

In the Holocene Optimum there was no collapse of the polar-bear population or "point of no return." The extent of Arctic summer sea ice then increased steadily, reaching a maximum during the very recent so-called Little Ice Age of 1500-1850. Potential confirmation that this was an unusually icy epoch comes from a newly published study by Durham University (in Britain) of the genetics of Arctic foxes on Iceland.

Greger Larson and his colleagues found that the remains of 17 Arctic foxes in Iceland from the ninth to the 12th centuries shared a single genetic signature, while the modern Icelandic fox population has five different genetic types. During the cold centuries, they infer, genetically diverse Arctic foxes from the Eurasian continent apparently reached Iceland via sea ice.

Anecdotal evidence suggests that the extent of summer Arctic sea ice then shrank after 1850, before expanding in the 1960s. Clearly, the Arctic Ocean's sea ice is both more variable and more vulnerable to warming than expected. But is the current rapid retreat caused only by warming? At least some of it might be caused by soot from dirty, coal-fired power stations. Some scientists have noticed that the decline in Arctic sea ice correlates better with the rapid growth of coal consumption in China than it does with global temperature. As the argument goes: Soot falling on white ice darkens it, which results in faster melting in summer sun.

Correlation does not always mean causation, but if soot is contributing to sea-ice melt, then it is moderately good news, because cleaning up soot emissions from power stations could be both cheaper and quicker than cutting carbon-dioxide emissions.

There's also the puzzling fact that Antarctic sea ice shows no sign of summer retreat, and the current winter's peak extent is well above average. The sea-dominated Southern Hemisphere is certainly warming more slowly than the land-dominated Northern Hemisphere, but it has still been warming. If warming is supposed to be "global," shouldn't sea ice retreat at both ends of the world? [The models cannot account for the difference: see here: "The negative SIE trends in most of the model runs over 1979 - 2005 are a continuation of an earlier decline, suggesting that the processes responsible for the observed increase over the last 30 years are not being simulated correctly."]

Rachel Carson's Silent Spring, published 50 years ago this month, effectively marked the birth of the modern environmental movement. "Silent Spring came as a cry in the wilderness, a deeply felt, thoroughly researched, and brilliantly written argument that changed the course of history," wrote Al Gore in his introduction to the 1994 edition.

Mr Gore reprised this theme on his website earlier this year, proudly comparing Carson's call to arms over pesticides to his own campaigning on the issue of climate change. He frequently compares the resistance he meets, and Carson met, to that which impeded the battle to establish the link between cancer and cigarette smoking. He accuses industry of "sowing doubt [about global warming] even more effectively than the tobacco companies before them."

The tobacco companies, said Mr Gore last year, "succeeded in delaying the implementation of the surgeon general's report for 40 years - 40 years! In every one of those 40 years the average number of Americans killed by cigarettes each year exceeded the total number of Americans killed in all of World War II: 450,000 per year. My sister was one of them. … It was evil, evil, evil."

Mr Gore may not be aware of a startling irony here. Carson's mentor and the source for much of her case that synthetic pesticides, and DDT in particular, were devastating bird life and causing widespread cancer in people, was himself a fervent denier of the link between tobacco smoking and lung cancer.

His name was Wilhelm Hueper. An immigrant to the United States from Germany (who shook off an embarrassing but brief enthusiasm for Nazism that led him to seek a job back in Hitler's Germany) he became the first director of the environmental cancer section of the US National Cancer Institute. There he single-mindedly pursued the idea that cancer was on the increase and that the cause was largely synthetic chemicals in the environment.

He encountered resistance, however, and not just from the chemical industry. Medical scientists were growing convinced that the rise of lung cancer was being caused by a rise in smoking. Hueper would have none of it. Here he is writing a paper called "Lung Cancers and their Causes" in 1955 in CA, a cancer journal for clinicians: "Industrial or industry-related atmospheric pollutants are to a great part responsible for the causation of lung cancer…cigarette smoking is not a major factor in the causation of lung cancer."

In her book, Carson refers to the work of Hueper throughout and made it clear he was her most important source. Describing a disease in trout, she wrote: "Dr. Hueper has described this epidemic as a serious warning that greatly increased attention must be given to controlling the number and variety of environmental carcinogens. 'If such preventive measures are not taken,' says Dr. Hueper, 'the stage will be set at a progressive rate for the future occurrence of a similar disaster to the human population.' "

The Hueper-Carson warning - that an epidemic of cancer caused by chemicals in the environment was on the way - caused one of the first eco-scares to go mainstream. The ecologist Paul Ehrlich, writing in Ramparts magazine in 1970, said that as a result of chemical pesticides, life expectancy in the United States would drop to 42 years by 1980 due to cancer epidemics. This was a widespread view. To this day many people think that pesticides causes much cancer.

Yet cancer death rates, corrected for average age of the population, are falling steadily. In the 1980s, a definitive study by Sir Richard Doll and Sir Richard Peto concluded that whereas 30% of Americans' cancer was caused by smoking, pollution caused at most a mere 5%. In 1996, the National Academy of Sciences concluded that levels of both synthetic and natural carcinogens are "so low that they are unlikely to pose an appreciable cancer risk".

Rachel Carson herself had a mastectomy and radiation therapy for breast cancer while writing Silent Spring and she died within two years of its publication at the age of 56. In his 1994 foreword, Al Gore hints that she might have been a victim of the chemicals she criticized: "Ironically, new research points strongly to a link between this disease and exposure to toxic chemicals. So in a sense, Carson was literally writing for her life."

Yet the evidence that DDT, the chemical that Carson's book is all about, can cause breast cancer doe not exist. After several studies, experts concluded that "weakly estrogenic organochlorine compounds such as PCBs, DDT, and DDE are not a cause of breast cancer."

When environmentalists attack a climate sceptic these days, they often accuse him or her of being the kind of person who would have denied the role of smoking in cancer. Tobacco denial "was transported whole cloth into the climate debate," said Al Gore in Aspen last year, citing the book Merchants of Doubt: How a Handful of Scientists Obscured the Truth on Issues from Tobacco Smoke to Global Warming by Naomi Oreskes and Erik M. Conway. Oreskes herself, apparently unaware of Carson's reliance on a tobacco denier for much of her argument, told a Yale seminar she was "stunned to discover myself how much the scientific evidence confirmed Rachel Carson's precautionary approach".

In any case, the charge that climate scepticism goes with tobacco denial is false. The best example that Oreskes has produced is a 1994 paper written by the climate sceptic Fred Singer challenging some statistics about passive smoking. Yet Singer does not deny that smoking causes cancer, has served on the advisory board of an anti-smoking organization and dislikes passive smoking.

To conclude from this history that climate alarmists have more in common with tobacco deniers than climate sceptics do would be simply to repeat Mr Gore's and Ms Oreskes's egregious mistake. The true lesson is that arguments should be discussed on their merits, not tarred by tenuous association.

Bill Moggridge, who invented the laptop computer in 1982, died last week. His idea of using a hinge to attach a screen to a keyboard certainly caught on big, even if the first model was heavy, pricey and equipped with just 340 kilobytes of memory. But if Mr. Moggridge had never lived, there is little doubt that somebody else would have come up with the idea.

The phenomenon of multiple discovery is well known in science. Innovations famously occur to different people in different places at the same time. Whether it is calculus (Newton and Leibniz), or the planet Neptune (Adams and Le Verrier), or the theory of natural selection (Darwin and Wallace), or the light bulb (Edison, Swan and others), the history of science is littered with disputes over bragging rights caused by acts of simultaneous discovery.

As Kevin Kelly argues in his book "What Technology Wants," there is an inexorability about technological evolution, expressed in multiple discovery, that makes it look as if technological innovation is an autonomous process with us as its victims rather than its directors.

Yet some inventions seem to have occurred to nobody until very late. The wheeled suitcase is arguably such a, well, case. Bernard Sadow applied for a patent on wheeled baggage in 1970, after a Eureka moment when he was lugging his heavy bags through an airport while a local worker effortlessly pushed a large cart past. You might conclude that Mr. Sadow was decades late. There was little to stop his father or grandfather from putting wheels on bags.

Mr. Sadow's bags ran on four wheels, dragged on a lead like a dog. Seventeen years later a Northwest Airlines pilot, Robert Plath, invented the idea of two wheels on a suitcase held vertically, plus a telescopic handle to pull it with. This "Rollaboard," now ubiquitous, also feels as if it could have been invented much earlier.

Or take the can opener, invented in the 1850s, eight decades after the can. Early 19th-century soldiers and explorers had to make do with stabbing bayonets into food cans. "Why doesn't somebody come up with a wheeled cutter?" they must have muttered (or not) as they wrenched open the cans.

Perhaps there's something that could be around today but hasn't been invented and that will seem obvious to future generations. Or perhaps not. It's highly unlikely that brilliant inventions are lying on the sidewalk ignored by the millions of entrepreneurs falling over each other to innovate. Plenty of terrible ideas are tried every day.

Understanding why inventions take so long may require mentally revisiting a long-ago time. For a poorly paid Napoleonic soldier who already carried a decent bayonet, adding a can opener to his limited kitbag was probably a waste of money and space. Indeed, going back to wheeled bags, if you consider the abundance of luggage porters with carts in the 1960s, the ease of curbside drop-offs at much smaller airports and the heavy iron casters then available, 1970 seems about the right date for the first invention of rolling luggage.

Just as it made little sense to invent the wheelie-case before the great expansion of air travel, so it made little sense to invent the laptop before 1982, when computers had begin to shrink, or the bicycle before the emergence of the motorcar had resulted in the appearance of smooth roads and pneumatic tires.

The more you examine the history of technology, the more evolutionary it looks. Invention is incremental rather than revolutionary, inevitable rather than idiosyncratic, and it emerges unplanned from the cross-fertilization of ideas. Once the Internet exists, the search engine will not be far behind. Even something that seems unique to one culture, such as the boomerang in Australia, turns out not to be. There are 3,300-year-old returning boomerangs in Tutankhamun's tomb in Egypt.

Your great-grandparents faced infectious diseases that hardly threaten you today: tuberculosis, polio, cholera, malaria, yellow fever, measles, mumps, rubella, smallpox, typhoid, typhus, tapeworm, hookworm…. But there's also a long list of modern illnesses that your great-grandparents barely knew: asthma, eczema, hay fever, food allergies, Crohn's disease, diabetes, multiple sclerosis, rheumatoid arthritis. The coincidence of the rise in these "inflammation" diseases, characterized by an overactive immune system, with the decline of infection is almost certainly not a coincidence.

Natural experiments in recent decades support the idea that while modern hygiene defeats infection, it also promotes allergy and autoimmunity. Finns isolated in an impoverished Soviet province had more parasites and fewer allergies than Finns in Finland. Swedes in clean Stockholm had three times as much asthma as Estonians in smoky Estonia. Ethiopians and Gambians got allergies when they lost their intestinal worms. Growing up on a farm greatly cuts allergy risk.

In a remarkable new book, "An Epidemic of Absence," Moises Velasquez-Manoff draws together hundreds of such studies to craft a powerful narrative carrying a fascinating argument. Infection with parasites prevents or ameliorates many diseases of inflammation. The author briefly cured his own hay fever and eczema by infecting himself with hookworms-before concluding that the price in terms of diarrhea and headaches was too high.

I've touched on the "hygiene hypothesis" in these pages before. In its cartoon form the argument-that in a clean world our immune system gets bored and turns on itself or on harmless pollen-isn't very convincing. But Mr. Velasquez-Manoff makes a far subtler, more persuasive case. Parasites have evolved to damp our immune responses so that they can stay in our bodies. Our immune system evolved to expect parasites to damp it. So in a world with no parasites, it behaves like a person leaning into the wind when it drops: The system falls over.

Moreover, just as brains outsource much of their development to the outside world-the visual system is refined by visual input, the language system can only develop in a language-using society-so the immune system seems to have happily outsourced much of its regulation to friendly microbes. Without them, the immune system becomes unbalanced.

Timing seems to be key. If you pick up Epstein-Barr virus and Helicobacter early in life from your mother pre-chewing your food, they seem to help protect you against inflammation diseases. Catch them later and they may cause multiple sclerosis and stomach cancer, respectively.

One of Mr. Velasquez-Manoff's most surprising chapters is on autism, a disorder that almost exactly parallels asthma in its recent rise among affluent, urban, mainly male, disproportionately firstborn people. Better diagnosis explains perhaps half the rise, but the brains of people with autism are often inflamed, and there's anecdotal evidence that infection with worms or viruses can tame autistic symptoms, at least temporarily.

There's also a link between inflammation during pregnancy, caused by allergy or autoimmune disease (or chronic, low-grade infection), and autism in the child. Acute infections during pregnancy, on the other hand, correlate with schizophrenic symptoms, which may be why schizophrenia is growing rarer while autism grows more common.

Mr. Velasquez-Manoff even raises the possibility that heart disease, diabetes, obesity and even some kinds of cancer and depression may owe something to an unbalanced immune system caused by an impoverished microbial ecosystem. Few doctors are yet willing to recommend deliberate infection with parasites to regulate the immune system, especially not for pregnant women. But that we should all be rearing our kids to be a little bit dirtier-in a healthy, rural, probiotic sort of way-looks more and more like good advice.

The astronomer Martin Rees recently coined the neat phrase "Copernican demotion" for science's habit of delivering humiliating disappointment to those who think that our planet is special. Copernicus told us the Earth was not at the center of the solar system; later astronomers found billions of solar systems in each of the billions of galaxies, demoting our home to a cosmic speck.

Mr. Rees says further Copernican demotion may loom ahead. "The entire panorama that astronomers can observe could be a tiny part of the aftermath of 'our' big bang, which is itself just one bang among a perhaps-infinite ensemble." Indeed, even our physics could be a parochial custom: Mr. Rees says that different universes could be governed by different rules and our "laws of nature" may be local bylaws.

Copernican demotion is a habit of biologists, too. Charles Darwin told us we were just another species among millions. In the 1950s, cytologists found we had one fewer pair of chromosomes than gorillas or chimpanzees-hardly good for our self-esteem. Anthropologists reported that apes could make tools, while paleontologists told us that our brains are possibly smaller than those of Neanderthals. Then came the news that, even within our own species, relative brain size had been shrinking, not growing, over the past 10,000 years.

Geneticists were no help either. In the 1960s, they discovered the startling fact that we had one-third as much DNA as grasshoppers and one-tenth as much as salamanders. For a while we stroked our egos by telling ourselves that we must have special genes to build and run our special brains. But it turned out not to be true. When the genome was sequenced at the turn of this century, and the genes counted, it transpired that we have the same number of genes as a mouse. Indeed, give or take a handful, we have the same genes as a mouse, just switched on in a different order and pattern.

Even when uniquely human features did emerge, they were humiliatingly mundane. In the 1990s, biochemists, led by Ajit Varki of the University of California at San Diego, found that about three million years ago, human beings developed a different version of a sugar called sialic acid on cell surfaces, possibly as a defense against malaria parasites. Intriguing, but hardly the key to the soul.

Now, at last, comes news that a team of scientists led by Daniel Geschwind of the University of California at San Francisco has found something special about the human brain. Using the latest gene sequencing machines and gene chips, they have compiled the "transcriptome" of the human "telencephalon," which means (in plain English) that they have identified those genes that are active in the main part of the brain. They then compared this list with equivalent data from chimpanzees and macaque monkeys.

What they found was that the frontal lobe of the human brain-the bit that seems to determine personality-stood out as unusual, even compared with the closely related chimpanzee. "Our analysis reveals a predominance of genes differentially expressed within the human frontal lobe and a striking increase in transcriptional complexity specific to the human lineage in the frontal lobe."

What's intriguing about the new results is not just that more genes seem to be active in the human frontal lobe, especially those involved in letting brain cells link with each other, but that the extra complexity clusters around certain "hub" genes. One of these is FOXP2, a gene that is known to be crucial to the development of language. In apes, monkeys and mice, FOXP2, seems to have fewer other genes at its beck and call than in human beings. As Mr. Geschwind's team puts it, "we experimentally validate an enrichment of human FOXP2 target genes" in the human frontal lobe.

A Copernican promotion at last?

The Times has published my article on Northumberlandia today.

On Monday the Princess Royal will officially declare open a new feature of the British countryside: a sculpture made of rock, and clad in clay, soil and grass, in the shape of an enormous, recumbent, female form. Northumberlandia, the Lady of the North, is a quarter of a mile long, 100ft high and weighs nearly 1.5 million tonnes. Designed by the artist Charles Jencks, she's the largest image of a woman anywhere in the world.

I am one of the people who sponsored, and bore some of the cost of, this extraordinary work of art, made without a penny of public money. It is on my land. Why did we do it? I find that most people seem to think that we - the Blagdon estate and the coal mining company, the Banks Group, which bore most of the cost and did all the work - must have some cunning motive: to dispose of waste, say, or to make money.

The truth is, we've done it for the benefit of the local community, as a happy side-effect of mining coal. The sculpture will be handed over to a charity, the Land Trust, to run, so there's no possibility of profit. The chief purpose of the project is to provide a public park with four miles of paths, some steep, some level, for people to explore for walks, picnics, runs, kite-flying, impromptu theatricals or whatever takes their fancy. It is art you can use. It has cost the public nothing, but it will be freely available.

When the Banks Group approached my family to dig out coal from under farmland we own, creating 150 local jobs, they also came with an imaginative suggestion. Instead of waiting ten years to put the rock back and restore the surface to woods and fields, which is the normal practice, why not put some of the rock to one side to make a new landscape feature that people can use long before the mine is restored?

A friend suggested commissioning Jencks, whose landform art is internationally famous, to design the landscape. Jencks's instruction was essentially to do with bulldozers what Michelangelo did with a chisel. It was his idea to make a woman. The distant Cheviot Hills, if you squint hard enough, look a bit like a recumbent body - and a female form makes a better range of hills than a male one. He set out to echo that view and make the resemblance explicit.

She was quickly called a "naked goddess", though she's neither nude - she's wearing grass - nor divine. Britain is so full of nimbys that even new, free, public parks get criticised; the most negative response came from a rare species hitherto not recorded breeding in this bit of Northumberland: a Tory councillor.

So I had no ulterior motive - beyond having "he helped to build the biggest woman in the world" carved on my tombstone. Nonetheless, Northumberlandia does teach an important lesson: that you cannot have prosperity without cheap energy. Imagine what Capability Brown (a Northumbrian) would have done if he had had bulldozers. In the 18th century thousands of poorly paid men with spades rearranged the landscape for Brown's clients. The rich consumed the physical energy of the poor. Being rich meant having the muscles of men and horses do things for you.

Today, being of average wealth means having machines driven by electricity and petrol to do things for you. The average British family consumes about as much energy in a day as if it had 500 Bradley Wigginses on stationary bicycles in the back room, pedalling flat out for eight-hour shifts. The replacement of muscle power, burning carbohydrates, with fossil power, burning hydrocarbons, has been one of the great liberators of history.

[For those who are interested, here's my calculation that led to the 500 Bradley Wigginses number:

the average Briton used about 5,000 watts (joules per second) -- see here

the average person on an exercise bicycle puts out about 50 watts

Bradley Wiggins can probably do twice that = 100 watts

Let's (implausibly) assume that he can do that for 8 hours without a break

So the average Briton needs about 50 BWs. (5000/100)

But even a BW needs 16 hours of rest between shifts so he actually needs 150 BWs

And there are 3-4 people in an average family so 3.5 x 150 = a little over 500 BWs.

Of course, this assumes that the BWs in your back room need no standard of life of their own, otherwise they would need BWs in their back rooms and so ad infinitum. Such is the gigantic effect of inorganic energy on our lives.]

Fossil fuels not only replaced drudgery, but liberated the land. Instead of using the landscape to produce our energy - hay, timber, water and bread for labourers - we now get it mostly from underground rocks. As a result, today's people live off about one quarter as much land as before the industrial revolution. Fossil fuels have done more than any other innovations to spare the rainforest.

Fertiliser, made with natural gas, roughly doubles the global average yield of farming, which roughly halves its acreage, which spares millions of square kilometres for rainforest, golf courses or parks in the shape of huge human bodies. The only reason we can spare 50 acres for a park in the shape of a woman is that the land is not needed by peasants to grow subsistence crops as it was in the Middle Ages.

And that innovation began in the north-east of England. It was Newcastle's coal that first fuelled the industrial revolution. An ancestor of mine, a buccaneering coal merchant named Richard Ridley, was the first person to put a steam engine in a coal mine, 298 years ago, near the north bank of the Tyne. I am proud of that. His main aim was to undercut the prevailing coal cartel called the Grand Allies and supply cheaper energy to London than his rivals.

So I fervently hope that one thing Northumberlandia will do, as well as giving people a chance to stretch their legs, is to remind them that coal, oil and gas - routinely denigrated as evil in school textbooks - helped not only to give us an average income per head 12 times higher than that of our pre-industrial ancestors in real terms, stamping out most starvation and disease along the way, but helped to spare the wilderness too, so that we can afford to make nice parks with paths spiralling up rounded hills.

The theory of selfish DNA was born as a throwaway remark in the book "The Selfish Gene" by Richard Dawkins, when he pondered why there is so much surplus DNA in the genomes of some animals and plants.

Perhaps, he suggested, our genomes are riddled with digital parasites, sequences of code that proliferate at our expense and aren't there to help "us"-that is, the organism as a whole-at all.

This theory has since explained a lot of puzzling phenomena. It might be the reason that there are so many insect species on the planet. Consider Wolbachia, a bacterium that lives inside the cells of more than two-thirds of insects. This parasite is passed through the female line, because insect sperm are stripped of their cell contents when they enter the egg.

That means that Wolbachia in a male insect is in an evolutionary dead-end. A gene trapped in a reproductive dead-end that mutates so as to find a way to get into another generation will prosper-even if it damages the interests of the creature it is part of. Indeed, Wolbachia's genes are so manipulative that they can convert male insects to females, kill males, induce virgin birth in females and even cause the offspring of males to die unless they carry the very same strain of Wolbachia as the father.

The genes of insects respond by mutating to suppress Wolbachia's gerrymandering of sexual reproduction. A sort of arms race results. But in the process, lots of different insect species emerge because of the incompatibility of the Wolbachia strains. The Creator's "inordinate fondness for beetles" (a phrase attributed to J.B.S. Haldane) may be caused partly by this parasite.

Wolbachia isn't the only object inside the cell with its own genes. Mitochondria, a cell's electrochemical "batteries," also have genes, left over from when they were bacteria that set up shop inside our distant ancestors' cells. Mitochondria pass through the female line too, and sure enough, their genes have a habit of castrating the male functions of more than 150 species of hermaphroditic plants. (This "cytoplasmic male sterility" is exploited by plant breeders seeking to generate hybrid varieties, because it prevents self-fertilization.)

Now it emerges that mitochondrial genes also can run amok in animals. This month a new scientific paper discussed the finding that small nematode worms of a certain species often carry a particular mitochondrial mutation-the absence of 786 letters of code from a crucial gene.

Experiments by scientists at Oregon and Portland State Universities leave no doubt that this mutation puts its carriers at a disadvantage. But they also show that, far from dying out, in the lab the mutation increases in abundance by 1% per generation.

How can this be? Genes bad for organisms are supposed to die out, not spread. The answer is that the mutation probably makes the worms breed as self-fertilizing hermaphrodites, rather than as males, so it thrives, selfishly, even as its owner suffers.

In recent years, some scientists have argued that such selfish genetic elements serve the greater good in the long run by making species more "evolvable," like insects, and that this explains their existence. Persuasive evidence against this, and in favor of the idea that they are harmful parasites that generate greater evolvability only as a side effect, comes from asexual species.

In asexual animals or plants, evolutionary diversification is much slower because of the lack of genetic remixing that happens during sex. So selfish elements should be welcomed in such lineages if evolvability is a net benefit. Instead-as shown by some tiny animals, called rotifers, that have not had sex for 80 million years-selfish DNA is generally purged from the genomes of asexual species as a nuisance.

Truly, the more we understand what happens within and between genes, the more innocent the human world seems.

So did we or didn't we? Last week saw the publication of two new papers with diametrically opposed conclusions about whether non-African people have Neanderthal-human hybrids among their ancestors-a result of at least some interspecies dalliance in the distant past.

That non-Africans share 1% to 4% of their genomes with Neanderthals is not in doubt, thanks to the pioneering work of paleo-geneticists led by the Max Planck Institute's Svante Paabo. At issue is how to interpret that fact. Dr. Paabo originally recognized that there are two possible explanations, hybridization (which got all the press) or "population substructure."

The second explanation goes like this. Around 350,000 years ago, when the ancestors of Neanderthals first left Africa and began to populate Eurasia, the African population from which they came would not have been genetically homogeneous. The early Neanderthals would therefore have been more closely related to some of their African cousins than to others.

That would have continued to be true for long afterward, because the genes of northern Africans would not have mixed fully with those of southern Africans. It might still have been true when the ancestors of modern Eurasians left Africa, about 65,000 years ago. In other words, northern Africans might still have had genetic similarities to Neanderthals, compared with southern Africans, left over from more than 350,000 years ago-and they might have brought that genetic similarity with them to Europe.

It is this argument that Dr. Andrea Manica and Dr. Anders Eriksson have tested with mathematical modeling and found plausible. The model uses over 100 populations in Africa to represent a diversity of geographical races. "Hopefully," says Dr. Manica, "Everyone will become more cautious before invoking hybridization, and start taking into account that ancient populations differed from each other probably as much as modern populations do."

Dr. Paabo, however, along with Dr. David Reich of Harvard University and others, has now come to the opposite conclusion. Measuring the length of genetic sequences that remain intact in the DNA shared by modern people and Neanderthals, these researchers infer that "the last gene flow from Neanderthals into Europeans likely occurred 37,000-86,000 years ago, and most likely 47,000-65,000 years ago." That is much too late for the substructure theory: Neanderthals were a separate species long before then. But because this time frame matches the period of modern people's exodus from Africa, it strongly supports the notion of recent interbreeding.

Moreover, as Drs. Paabo and Reich point out, there is intriguing archeological evidence for where and when the interbreeding might have happened. Around 100,000 years ago, modern humans occupied caves in what is now Israel. By 70,000 years ago, in cooler times, the Neanderthals were in the area. By 50,000 years ago, the moderns had come to the Middle East to stay. These long epochs of to-and-fro migration must have given opportunities for sexual overlap.

The population-substructure argument also struggles to explain an even larger genetic overlap between yet another extinct human form, the "Denisovans," and people from Southeast Asia and Australasia, presumably originating from an eastern exodus out of Africa. With the addition of this case, the substructure argument requires two different, distinct human groups with different samples of pre-modern-human genetic material (Neanderthal and Denisovan) to have migrated at different times-and to have ended up in the same parts of the world as ancient populations whose genes they happen to share.

It is probably more plausible (and newsworthy) to imagine that when modern people spread around the Indian Ocean, they too encountered a distantly related human species and dallied with them under the palms.

I have a long article on apocalyptic predictions in Wired Magazine. Here's a version with about 70 links to sources. I have also added in a few paragraphs on falling sperm counts and on species extinction: these were edited from the published version of the article for space reasons.

"Who or what will cause the 20120 apocalypse?" This is the question posed by the website 2012apocalypse.net. "Super volcanos? Pestilence and disease? Asteroids? Comets? Antichrist? Global warming? Nuclear war?" the site's authors are impressively open-minded about the cause of the catastrophe that is coming at 11:11 pm on December 21 this year. but they have no doubt it will happen. after all, not only does the Mayan Long Count calendar end that day, but "the sun will be aligned with the center of the Milky Way for the first time in about 26,000 years."

Case closed: Sell your possessions and live for today.

When the sun rises on December 22, as it surely will, do not expect apologies or even a rethink. No matter how often apocalyptic predictions fail to come true, another one soon arrives. And the prophets of apocalypse always draw a following-from the 100,000 Millerites who took to the hills in 1843, awaiting the end of the world, to the thousands who believed in Harold Camping, the Christian radio broadcaster who forecast the final rapture in both 1994 and 2011.

Predictions of global famine and the end of oil in the 1970s proved just as wrong as end-of-the-world forecasts from millennialist priests. Yet there is no sign that experts are becoming more cautious about apocalyptic promises. If anything, the rhetoric has ramped up in recent years. Echoing the Mayan calendar folk, theBulletin of the Atomic Scientists moved its Doomsday Clock one minute closer to midnight at the start of 2012, commenting: "The global community may be near a point of no return in efforts to prevent catastrophe from changes in Earth's atmosphere."

Over the five decades since the success of Rachel Carson's Silent Spring in 1962 and the four decades since the success of the Club of Rome's The Limits to Growth in 1972, prophecies of doom on a colossal scale have become routine. Indeed, we seem to crave ever-more-frightening predictions-we are now, in writer Gary Alexander's word, apocaholic. The past half century has brought us warnings of population explosions, global famines, plagues, water wars, oil exhaustion, mineral shortages, falling sperm counts, thinning ozone, acidifying rain, nuclear winters, Y2K bugs, mad cow epidemics, killer bees, sex-change fish, cell-phone-induced brain-cancer epidemics, and climate catastrophes.

So far all of these specters have turned out to be exaggerated. True, we have encountered obstacles, public-health emergencies, and even mass tragedies. But the promised Armageddons-the thresholds that cannot be uncrossed, the tipping points that cannot be untipped, the existential threats to Life as We Know It-have consistently failed to materialize. To see the full depth of our apocaholism, and to understand why we keep getting it so wrong, we need to consult the past 50 years of history.

The classic apocalypse has four horsemen, and our modern version follows that pattern, with the four riders being chemicals (DDT, CFCs, acid rain), diseases (bird flu, swine flu, SARS, AIDS, Ebola, mad cow disease), people (population, famine), and resources (oil, metals). Let's visit them each in turn.

The first horseman: chemicals

Silent Spring, published 50 years ago this year, was instrumental in the emergence of modern environmentalism. "Without this book, the environmental movement might have been long delayed or never have developed at all," Al Gore wrote in his introduction to the 1994 edition. Carson's main theme was that the use of synthetic pesticides-DDT in particular-was causing not only a massacre of wildlife but an epidemic of cancer in human beings. One of her chief inspirations and sources for the book was Wilhelm Hueper, the first director of the environmental arm of the National Cancer Institute. So obsessed was Hueper with his notion that pesticides and other synthetic chemicals were causing cancers (and that industry was covering this up) that he strenuously opposed the suggestion that tobacco-smoking take any blame. Hueper wrote in a 1955 paper called "Lung Cancers and Their Causes," published in CA: A Cancer Journal for Clinicians, "Industrial or industry-related atmospheric pollutants are to a great part responsible for the causation of lung cancer … cigarette smoking is not a major factor in the causation of lung cancer."

In fact, of course, the link between smoking and lung cancer was found to be ironclad. But the link between modern chemicals and cancer is sketchy at best. Even DDT, which clearly does pose health risks to those unsafely exposed, has never been definitively linked to cancer. In general, cancer incidence and death rates, when corrected for the average age of the population, have been falling now for 20 years.

By the 1970s the focus of chemical concern had shifted to air pollution. Life magazine set the scene in January 1970: "Scientists have solid experimental and theoretical evidence to support … the following predictions: In a decade, urban dwellers will have to wear gas masks to survive air pollution … by 1985 air pollution will have reduced the amount of sunlight reaching earth by one half." Instead, driven partly by regulation and partly by innovation, both of which dramatically cut the pollution coming from car exhaust and smokestacks, ambient air quality improved dramatically in many cities in the developed world over the following few decades. Levels of carbon monoxide, sulphur dioxide, nitrogen oxides, lead, ozone, and volatile organic compounds fell and continue to fall.

In the 1980s it was acid rain's turn to be the source of apocalyptic forecasts. In this case it was nature in the form of forests and lakes that would bear the brunt of human pollution. The issue caught fire in Germany, where a cover story in the news magazine Der Spiegel in November 1981 screamed: "THE FOREST DIES." Not to be outdone, Stern magazine declared that a third of Germany's forests were already dead or dying. Bernhard Ulrich, a soil scientist at the University of Göttingen, said it was already too late for the country's forests: "They cannot be saved." Forest death, or waldsterben, became a huge story across Europe. "The forests and lakes are dying. Already the damage may be irreversible," journalist Fred Pearce wrote in New Scientist in 1982. It was much the same in North America: Half of all US lakes were said to be becoming dangerously acidified, and forests from Virginia to central Canada were thought to be suffering mass die-offs of trees.

Conventional wisdom has it that this fate was averted by prompt legislative action to reduce sulphur dioxide emissions from power plants. That account is largely false. There was no net loss of forest in the 1980s to reverse. In the US, a 10-year government-sponsored study involving some 700 scientists and costing about $500 million reported in 1990 that "there is no evidence of a general or unusual decline of forests in the United States and Canada due to acid rain" and "there is no case of forest decline in which acidic deposition is known to be a predominant cause." (See also: here and here.) In Germany, Heinrich Spiecker, director of the Institute for Forest Growth, was commissioned by a Finnish forestry organization to assess the health of European forests. He concluded that they were growing faster and healthier than ever and had been improving throughout the 1980s. "Since we began measuring the forest more than 100 years ago, there's never been a higher volume of wood … than there is now," Spiecker said. (Ironically, one of the chief ingredients of acid rain-nitrogen oxide-breaks down naturally to become nitrate, a fertilizer for trees.) As for lakes, it turned out that their rising acidity was likely caused more by reforestation than by acid rain; one study suggested that the correlation between acidity in rainwater and the pH in the lakes was very low. The story of acid rain is not of catastrophe averted but of a minor environmental nuisance somewhat abated.

The threat to the ozone layer came next. In the 1970s scientists discovered a decline in the concentration of ozone over Antarctica during several springs, and the Armageddon megaphone was dusted off yet again. The blame was pinned on chlorofluorocarbons, used in refrigerators and aerosol cans, reacting with sunlight. The disappearance of frogs and an alleged rise of melanoma in people were both attributed to ozone depletion. So too was a supposed rash of blindness in animals: Al Gore wrote in 1992 about blind salmon and rabbits ["hunters now report finding blind rabbits; fisherman catch blind salmon."], while The New York Times reported "an increase inTwilight Zone-type reports of sheep and rabbits with cataracts" in Patagonia. But all these accounts proved incorrect. The frogs were dying of a fungal disease spread by people; the sheep had viral pinkeye; the mortality rate from melanoma actually leveled off during the growth of the ozone hole; and as for the blind salmon and rabbits, they were never heard of again.

There was an international agreement to cease using CFCs by 1996. But the predicted recovery of the ozone layer never happened: The hole stopped growing before the ban took effect, then failed to shrink afterward. The ozone hole still grows every Antarctic spring, to roughly the same extent each year. Nobody quite knows why. Some scientists think it is simply taking longer than expected for the chemicals to disintegrate; a few believe that the cause of the hole was misdiagnosed in the first place. Either way, the ozone hole cannot yet be claimed as a looming catastrophe, let alone one averted by political action.

[The next chemical scare was "endocrine disruptors", chemicals that mimic sex hormones. In a book entitled Our Stolen Future, published in 1996, many plastics, pesticides and other man-made chemicals stood accused of changing the sex of fish, shrinking the penises of alligators and depressing the sperm counts of men. "Chemicals that disrupt hormone messages have the power to rob us of rich possibilities that have been the legacy of our species and, indeed, the essence of our humanity. There may be fates worse than extinction," warned the three authors melodramatically.

In 1992, Danish researchers reported that human sperm counts had fallen by 50% in 50 years, but they did so by comparing different studies in different places at different times. Other studies failed to replicate the results and by 2011 the sperm-count fall had been laid to rest as a myth following a 15-year study of Danish national-service recruits, which found "no indication that semen quality has changed". It also noted that "there is only very limited epidemiologic evidence to support the broader endocrine disruption hypothesis". Few researchers now believe there was ever much of an issue here.]

Repeatedly throughout the past five decades,the imminent advent of a new pandemic has been foretold. The 1976 swine flu panic was an early case. Following the death of a single recruit at Fort Dix, the Ford administration vaccinated more than 40 million Americans, but more people probably died from adverse reactions to the vaccine than died of swine flu.

A few years later, a fatal virus did begin to spread at an alarming rate, initially through the homosexual community. AIDS was soon, rightly, the focus of serious alarm. But not all the dire predictions proved correct. "Research studies now project that one in five-listen to me, hard to believe-one in five heterosexuals could be dead from AIDS at the end of the next three years. That's by 1990. One in five," Oprah Winfrey warned in 1987 (Quoted in "Bias", by Bernard Goldberg. Regnery Publishing 2002.)

Bad as AIDS was, the broad-based epidemic in the Americas, Europe, and Asia never materialized as feared, though it did in Africa. In 2000 the US National Intelligence Council predicted that HIV/AIDS would worsen in the developing world for at least 10 years and was "likely to aggravate and, in some cases, may even provoke economic decay, social fragmentation and political destabilization in the hardest hit countries in the developing and former communist worlds."

Yet the peak of the epidemic had already passed in the late 1990s, and today AIDS is in slow retreat throughout the world. New infections were 20 percent lower in 2010 than in 1997, and the lives of more than 2.5 million people have been saved since 1995 by antiretroviral treatment. "Just a few years ago, talking about ending the AIDS epidemic in the near term seemed impossible, but science, political support, and community responses are starting to deliver clear and tangible results," UNAIDS executive director Michel Sidibé wrote last year.

The emergence of AIDS led to a theory that other viruses would spring from tropical rain forests to wreak revenge on humankind for its ecological sins. That, at least, was the implication of Laurie Garrett's 1994 book, The Coming Plague: Newly Emerging Diseases in a World Out of Balance. The most prominent candidate was Ebola, the hemorrhagic fever that starred in Richard Preston's The Hot Zone, published the same year. Writer Stephen King called the book "one of the most horrifying things I've ever read." Right on cue, Ebola appeared again in the Congo in 1995, but it soon disappeared. Far from being a harbinger, HIV was the only new tropical virus to go pandemic in 50 years.

In the 1980s British cattle began dying from mad cow disease, caused by an infectious agent in feed that was derived from the remains of other cows. When people, too, began to catch this disease, predictions of the scale of the epidemic quickly turned terrifying: Up to 136,000 would die, according to one study. A pathologist warned that the British "have to prepare for perhaps thousands, tens of thousands, hundreds of thousands, of cases of vCJD [new variant Creutzfeldt-Jakob disease, the human manifestation of mad cow] coming down the line." Yet the total number of deaths so far in the UK has been 176, with just five occurring in 2011 and none so far in 2012.

In 2003 it was SARS, a virus from civet cats, that ineffectively but inconveniently led to quarantines in Beijing and Toronto amid predictions of global Armageddon. SARS subsided within a year, after killing just 774 people. In 2005 it was bird flu, described at the time by a United Nations official as being "like a combination of global warming and HIV/AIDS 10 times faster than it's running at the moment." The World Health Organization's official forecast was 2 million to 7.4 million dead. In fact, by late 2007, when the disease petered out, the death toll was roughly 200. In 2009 it was Mexican swine flu. WHO director general Margaret Chan said: "It really is all of humanity that is under threat during a pandemic." The outbreak proved to be a normal flu episode.

The truth is, a new global pandemic is growing less likely, not more. Mass migration to cities means the opportunity for viruses to jump from wildlife to the human species has not risen and has possibly even declined, despite media hype to the contrary. Water- and insect-borne infections-generally the most lethal-are declining as living standards slowly improve. It's true that casual-contact infections such as colds are thriving-but only by being mild enough that their victims can soldier on with work and social engagements, thereby allowing the virus to spread. Even if a lethal virus does go global, the ability of medical science to sequence its genome and devise a vaccine or cure is getting better all the time.

The third horseman: people

Of all the cataclysmic threats to human civilization envisaged in the past 50 years, none has drawn such hyperbolic language as people themselves. "Human beings are a disease, a cancer of this planet," says Agent Smith in the filmThe Matrix. Such rhetoric echoes real-life activists like Paul Watson of the Sea Shepherd Conservation Society: "We need to radically and intelligently reduce human populations to fewer than one billion … Curing a body of cancer requires radical and invasive therapy, and therefore, curing the biosphere of the human virus will also require a radical and invasive approach."

On a "stinking hot" evening in a taxi in Delhi in 1966, as Paul Ehrlich wrote in his best seller, The Population Bomb, "the streets seemed alive with people. People eating, people washing, people sleeping. People visiting, arguing, and screaming. People thrusting their hands through the taxi window, begging. People defecating and urinating. People clinging to buses. People herding animals. People, people, people, people." Ehrlich's conclusion was bleak: "The train of events leading to the dissolution of India as a viable nation" was already in progress. And other experts agreed. "It is already too late to avoid mass starvation," said Denis Hayes, organizer of the first Earth Day in 1970. Sending food to India was a mistake and only postponed the inevitable, William and Paul Paddock wrote in their best seller,Famine-1975!

What actually happened was quite different. The death rate fell. Famine became rarer. The population growth rate was cut in half, thanks chiefly to the fact that as babies stop dying, people stop having so many of them. Over the past 50 years, worldwide food production per capita has risen, even as the global population has doubled. Indeed, so successful have farmers been at increasing production that food prices fell to record lows in the early 2000s and large parts of western Europe and North America have been reclaimed by forest. (A policy of turning some of the world's grain into motor fuel has reversed some of that decline and driven prices back up.)

Meanwhile, family size continues to shrink on every continent. The world population will probably never double again, whereas it quadrupled in the 20th century. With improvements in seeds, fertilizers, pesticides, transport, and irrigation still spreading across Africa, the world may well feed 9 billion inhabitants in 2050-and from fewer acres than it now uses to feed 7 billion.

The fourth horseman: resources

In 1977 President Jimmy Carter went on television and declared: "World oil production can probably keep going up for another six or eight years. But sometime in the 1980s, it can't go up anymore. Demand will overtake production." He was not alone in this view. The end of oil and gas had been predicted repeatedly throughout the 20th century. In 1922 President Warren Harding created the US Coal Commission, which undertook an 11-month survey that warned, "Already the output of [natural] gas has begun to wane. Production of oil cannot long maintain its present rate." (Quoted in Bradley, R.L. 2007. Capitalism at Work. Scrivener Press. P 206.) In 1956, M. King Hubbert, a Shell geophysicist, forecast that gas production in the US would peak at about 14 trillion cubic feet per year sometime around 1970.

All these predictions failed to come true. Oil and gas production have continued to rise during the past 50 years. Gas reserves took an enormous leap upward after 2007, as engineers learned how to exploit abundant shale gas. In 2011 the International Energy Agency estimated that global gas resources would last 250 years. Although it seems likely that cheap sources of oil may indeed start to peter out in coming decades, gigantic quantities of shale oil and oil sands will remain available, at least at a price. Once again, obstacles have materialized, but the apocalypse has not. Ever since Thomas Robert Malthus, doomsayers have tended to underestimate the power of innovation. In reality, driven by price increases, people simply developed new technologies, such as the horizontal drilling technique that has helped us extract more oil from shale.

It was not just energy but metals too that were supposed to run out. In 1970 Harrison Brown, a member of the National Academy of Sciences, forecast in Scientific American that lead, zinc, tin, gold, and silver would all be gone by 1990. The best-selling book The Limits to Growth was published 40 years ago by the Club of Rome, a committee of prominent environmentalists with a penchant for meeting in Italy. The book forecast that if use continued to accelerate exponentially, world reserves of several metals could run out by 1992 and help precipitate a collapse of civilization and population in the subsequent century, when people no longer had the raw materials to make machinery. These claims were soon being repeated in schoolbooks. "Some scientists estimate that the world's known supplies of oil, tin, copper, and aluminum will be used up within your lifetime," one read. In fact, as the results of a famous wager between Paul Ehrlich and economist Julian Simon later documented, the metals did not run out. Indeed, they grew cheaper. Ehrlich, who claimed he had been "goaded" into the bet, growled, "The one thing we'll never run out of is imbeciles."

[Far from being congratulated for this feat, Simon was widely attacked. So he offered one of his critics, William Conway of the New York Zoological Society, a bet on species extinction: "I'll bet that the number of scientifically-proven species extinctions in the world in the year 2000 is not even one-hundredth as large as the 40,000 as conventionally forecast; any other year will be fine, too."

The estimate of 40,000 species going extinct a year came from the conservationist Norman Myers in 1979, though it was originally more an assumption than a measurement: "Let us suppose that, as a consequence of this man-handling of natural environments, the final one quarter of this century witnesses the elimination of one million species - a far from unlikely prospect. This would work out, during the course of 25 years, at an average extinction rate of 40,000 species per year."

Not that Myers's number was much different from those being suggested by others. The Harvard biologist E.O.Wilson has regularly spoken of 27,000 species going extinct each year, a number reached by calculating how much habitat is being lost and applying a mathematical formula called the species-area curve. However, a recent study by Stephen Hubbell and Fangliang He, of the University of California at Los Angeles, found that these "estimated" extinction rates are "almost always much higher than those actually observed" -- loss of forest habitat does not result in species loss at the rate predicted by the theory.

This may explain why actual recorded extinction rates, though bad enough, are so much lower than predicted. Whereas Wilson's 27,000 annual extinctions should be producing 26 bird and 13 mammal extinctions a year, in fact, on a comprehensive list kept by the American Museum of Natural History, extinctions of bird and mammal species peaked at 1.6 a year around 1900 and have since dropped to about 0.2 a year. So far 1.3% of mammals (69/4428) and 1.4% of birds (129/8971) have gone extinct in four centuries.

Each extinction is a tragedy. But this is a far cry from the extinction rates forecast by Dillon Ripley, secretary of the Smithsonian Institute, (75-80% of species by 1995), Paul and Anne Ehrlich (50% by 2005) and Thomas Lovejoy for the Global 2000 Report to President Carter (15-20% by 2000).]

Conclusion

Over the past half century, none of our threatened eco-pocalypses have played out as predicted. Some came partly true; some were averted by action; some were wholly chimerical. This raises a question that many find discomforting: With a track record like this, why should people accept the cataclysmic claims now being made about climate change? After all, 2012 marks the apocalyptic deadline of not just the Mayans but also a prominent figure in our own time: Rajendra Pachauri, head of the Intergovernmental Panel on Climate Change, who said in 2007 that "if there's no action before 2012, that's too late … This is the defining moment."

So, should we worry or not about the warming climate? It is far too binary a question. The lesson of failed past predictions of ecological apocalypse is not that nothing was happening but that the middle-ground possibilities were too frequently excluded from consideration. In the climate debate, we hear a lot from those who think disaster is inexorable if not inevitable, and a lot from those who think it is all a hoax. We hardly ever allow the moderate "lukewarmers" a voice: those who suspect that the net positive feedbacks from water vapor in the atmosphere are low, so that we face only 1 to 2 degrees Celsius of warming this century; that the Greenland ice sheet may melt but no faster than its current rate of less than 1 percent per century; that net increases in rainfall (and carbon dioxide concentration) may improve agricultural productivity; that ecosystems have survived sudden temperature lurches before; and that adaptation to gradual change may be both cheaper and less ecologically damaging than a rapid and brutal decision to give up fossil fuels cold turkey.

We've already seen some evidence that humans can forestall warming-related catastrophes. A good example is malaria, which was once widely predicted to get worse as a result of climate change. Yet in the 20th century, malaria retreated from large parts of the world, including North America and Russia, even as the world warmed. Malaria-specific mortality plummeted in the first decade of the current century by an astonishing 25 percent. The weather may well have grown more hospitable to mosquitoes during that time. But any effects of warming were more than counteracted by pesticides, new antimalarial drugs, better drainage, and economic development. Experts such as Peter Gething at Oxford argue that these trends will continue, whatever the weather.

Just as policy can make the climate crisis worse-mandating biofuels has not only encouraged rain forest destruction, releasing carbon, but driven millions into poverty and hunger-technology can make it better. If plant breeders boost rice yields, then people may get richer and afford better protection against extreme weather. If nuclear engineers make fusion (or thorium fission) cost-effective, then carbon emissions may suddenly fall. If gas replaces coal because of horizontal drilling, then carbon emissions may rise more slowly. Humanity is a fast-moving target. We will combat our ecological threats in the future by innovating to meet them as they arise, not through the mass fear stoked by worst-case scenarios.

Identifying unique features of human beings is a cottage industry in psychology. In his book "Stumbling on Happiness," the Harvard psychologist Daniel Gilbert jokes that every member of his profession lives under the obligation at some time in his career to complete a sentence which begins: "The human being is the only animal that..." Those who have completed the sentence with phrases like "makes tools," "is conscious" or "can imitate" have generally now conceded that some other animals also have these traits.

Plenty of human uniqueness remains. After all, uniqueness is everywhere in the biological world: Elephants and worms also have unique features. As fast as one scientist demotes human beings from being unique in one trait, another scientist comes up with a new unique trait: grandparental care, for instance, or extra spines on the pyramidal cells of our prefrontal cortex.

In such debates, scientists must sail between the Scylla of human hubris (for example, saying that a dreaming dog is not equivalent to a dreaming person) and the Charybdis of mistakenly attributing human traits to animals. A case of the latter problem was pointed out this month in a paper by Marco Vasconcelos and Alex Kacelnik of Oxford University writing with Karen Hollis and Elise Nowbahari of the University of Paris.

It concerned two experiments. In one, scientists at the University of Chicago put two rats in an arena, one held by a restrainer, the other free. They found that the free rat learned to "intentionally and quickly open the restrainer and free the cagemate." They interpreted this result as "providing strong evidence for biological roots of empathically motivated helping behavior."

In the other case, Drs. Hollis and Nowbahari themselves did a very similar experiment with ants. They found that ants were prepared to rescue fellow ants held in a nylon snare and showing obvious distress. Just like the rats, the hero ants would chew at the restraints (though not if the victims were anesthetized or from different colonies or species). Happy to describe such behavior as "pro-social," they did not go so far as to attribute empathy to the ants. There was no reason to think that the hero ants were motivated by a wish to alleviate the suffering of the victims. More likely, they possessed a self-interested instinct to help get a co-worker back to work.

Ant biting the nylon snare holding a nestmate down

In his 1759 book the "Theory of the Moral Sentiments," philosopher Adam Smith argued that empathy (he called it sympathy) was motivated by the capacity to imagine being another person. "When I condole with you for the loss of your only son, in order to enter into your grief, I do not consider what I, a person of such a character and profession, should suffer, if I had a son, and if that son was unfortunately to die; but I consider what I should suffer if I was really you; and I not only change circumstances, but I change persons and characters. My grief, therefore, is entirely upon your account, and not in the least upon my own. It is not, therefore, in the least selfish." (Pt 7, section 3, chap 1, 4th para.)

Either we must conclude that even ants are capable of such empathic suffering, which seems absurd, or we must view the rat experiments as proving nothing about psychological motivation, leaving human beings on a pedestal. In the same way that evolution by natural selection can produce purposeful designs without an intelligent designer to prefigure the purpose, so animals can show behavior that evolved to be purposeful but is not psychologically motivated. The rats may decide to free their fellow rats because they're descended from rats that helped relatives and thus allowed their genes to thrive, not because they feel their fellows' pain.

And human beings? Can we be so sure it is fellow-feeling rather than instinct that drives us to our virtuous as well as our vicious actions?

I argued last week that the way to combat confirmation bias-the tendency to behave like a defense attorney rather than a judge when assessing a theory in science-is to avoid monopoly. So long as there are competing scientific centers, some will prick the bubbles of theory reinforcement in which other scientists live.

For constructive critics, this is the problem with modern climate science. They don't think it's a conspiracy theory, but a monopoly that clings to one hypothesis (that carbon dioxide will cause dangerous global warming) and brooks less and less dissent. Again and again, climate skeptics are told they should respect the consensus, an admonition wholly against the tradition of science.

Last month saw two media announcements of preliminary new papers on climate. One, by a team led by physicist Richard Muller of the University of California, Berkeley, concluded "the carbon dioxide curve gives a better match than anything else we've tried" for the (modest) 0.8 Celsius-degree rise in global average temperatures over land during the past half-century-less, if ocean is included. He may be right, but such curve-fitting reasoning is an example of confirmation bias. The other, by a team led by the meteorologist Anthony Watts, a skeptical gadfly, confirmed its view that the Muller team's numbers are too high-because "reported 1979-2008 U.S. temperature trends are spuriously doubled" by bad thermometer siting and unjustified "adjustments."

Much published research on the impact of climate change consists of confirmation bias by if-then modeling, but critics also see an increasing confusion between model outputs and observations. For example, in estimating how much warming is expected, the most recent report of the Intergovernmental Panel on Climate Change uses three methods, two based entirely on model simulations.

[Here is the actual wording: "Basing our assessment on a combination of several independent lines of evidence, as summarised in Box 10.2 Figures 1 and 2, including observed climate change and the strength of known feedbackssimulated in GCMs, we conclude that the global mean equilibrium warming for doubling CO2, or 'equilibrium climate sensitivity', is likely to lie in the range 2°C to 4.5°C, with a most likely value of about 3°C."]

The late novelist Michael Crichton, in his prescient 2003 lecture criticizing climate research, said: "To an outsider, the most significant innovation in the global-warming controversy is the overt reliance that is being placed on models.... No longer are models judged by how well they reproduce data from the real world-increasingly, models provide the data. As if they were themselves a reality."

It isn't just models, but the interpretation of real data, too. The rise and fall in both temperature and carbon dioxide, evident in Antarctic ice cores, was at first thought to be evidence of carbon dioxide driving climate change. Then it emerged that the temperature had begun rising centuries earlier than carbon dioxide. Rather than abandon the theory, scientists fell back on the notion that the data jibed with the possibility that rising carbon dioxide levels were reinforcing the warming trend in what's called a positive feedback loop. Maybe-but there's still no empirical evidence that this was a significant effect compared with a continuation of whatever first caused the warming.

The reporting of climate in the media is full of confirmation bias. Hot summers (in the U.S.) or wet ones (in the U.K.) are invoked as support for climate alarmism, whereas cold winters are dismissed as weather. Yale University's Dan Kahan and colleagues polled 1,500 Americans and found that, as they learned more about science, both believers and nonbelievers in dangerous climate change "become more skillful in seeking out and making sense of-or if necessary explaining away-empirical evidence relating to their groups' positions on climate change and other issues."

As one practicing scientist wrote anonymously to a blog in 2009: "honestly, if you know anything about my generation, we will do or say whatever it is we think we're supposed to do or say. There is no conspiracy, just a slightly cozy, unthinking myopia. Don't rock the boat."

Bring on the gadflies.

If, as I argued last week, scientists are just as prone as everybody else to confirmation bias ­ to looking for evidence to support rather than test their ideas ­ then how is it that science, unlike cults and superstitions, does change its mind and find new things?

The answer was spelled out by the psychologist Raymond Nickerson of Tufts University in a paper written in 1998: "It is not so much the critical attitude that individual scientists have taken with respect to their own ideas that has given science the success it has enjoyed... but more the fact that individual scientists have been highly motivated to demonstrate that hypotheses that are held by some other scientist(s) are false."

Most scientists do not try to disprove their ideas; rivals do it for them. Only when those rivals fail is the theory bomb-proof. The physicist Robert Millikan, (who showed minor confirmation bias in his own work on the charge of the electron by omitting outlying observations that did not fit his hypothesis) devoted more than 10 years to trying to disprove Einstein¹s theory that light consisted of particles (photons). His failure convinced almost everybody but himself that Einstein was right.

The solution to confirmation bias in science, then, is not to try to teach it out of people, for that goes too much against the grain of human nature. Dr. Nickerson points out that the history of science is replete not only with examples of great scientists tenaciously persisting with theories "long after the evidence against them had become sufficiently strong to persuade others without the same vested interests to discard them" but also with brilliant people who remained wedded to their pet hates.

Galileo rejected Kepler's lunar explanation of tides; Huygens objected to Newton's concept of gravity; Humphrey Davy detested John Dalton's atomic theory; Einstein denied quantum theory.

No, the reason that science progresses despite confirmation bias is partly that it makes testable predictions, but even more that it prevents monopoly. By dispersing its incentives among many different centers, it allows scientists to check each other's prejudices. When a discipline defers to a single authority, and demands adherence to a set of beliefs, then it becomes a cult. Medicine did this with Galen and psychoanalysis with Freud.

A recent example is the case of malaria and climate. In the early days of global-warming research, scientists argued that warming would worsen malaria by increasing the range of mosquitoes. "Malaria and dengue fever are two of the mosquito-borne diseases most likely to spread dramatically as global temperatures head upward," said the Harvard Medical School's Paul Epstein in Scientific American in 2000, in a warning typical of many.

Carried away by confirmation bias, scientists modeled the future worsening of malaria, and the Intergovernmental Panel on Climate Change accepted this as a given. When Paul Reiter, an expert on insect-borne diseases at the Pasteur Institute, begged to differ-pointing out that malaria¹s range was shrinking and was limited by factors other than temperature-he had an uphill struggle. "After much effort and many fruitless discussions," he said, "I ... resigned from the IPCC project [but] found that my name was still listed. I requested its removal, but was told it would remain because 'I had contributed.' It was only after strong insistence that I succeeded in having it removed."

Yet Dr. Reiter has now been vindicated. In a recent paper, Peter Gething of Oxford University and his colleagues concluded that widespread claims that rising mean temperatures had already worsened malaria mortality were "largely at odds with observed decreasing global trends" and that proposed future effects of rising temperatures are "up to two orders of magnitude smaller than those that can be achieved by the effective scale-up of key control measures."

The IPCC, in other words, learned the hard way the value of letting mavericks and gadflies challenge confirmation bias.

There's a myth out there that has gained the status of a cliché: that scientists love proving themselves wrong, that the first thing they do after constructing a hypothesis is to try to falsify it. Professors tell students that this is the essence of science.

Yet most scientists behave very differently in practice. They not only become strongly attached to their own theories; they perpetually look for evidence that supports rather than challenges their theories. Like defense attorneys building a case, they collect confirming evidence.

In this they're only human. In all walks of life we look for evidence to support our beliefs, rather than to counter them. This pervasive phenomenon is known to psychologists as "confirmation bias." It is what keeps all sorts of charlatans in business, from religious cults to get-rich-quick schemes. As the philosopher/scientist Francis Bacon noted in 1620: "And such is the way of all superstition, whether in astrology, dreams, omens, divine judgments, or the like; wherein men, having a delight in such vanities, mark the events where they are fulfilled, but where they fail, though this happen much oftener, neglect and pass them by."

Just as hypochondriacs and depressives gather ample evidence that they're ill or ill-fated, ignoring that which implies they are well or fortunate, so physicians managed to stick with ineffective measures such as bleeding, cupping and purging for centuries because the natural recovery of the body in most cases provided ample false confirmation of the efficacy of false cures. Homeopathy relies on the same phenomenon to this day.

Moreover, though we tell students in school that, as Karl Popper argued, science works by falsifying hypotheses, we teach them the very opposite-to build a case by accumulating evidence in support of an argument.

The phrase "confirmation bias" itself was coined by a British psychologist named Peter Wason in 1960. His classic demonstration of why it was problematic was to give people the triplet of numbers "2-4-6" and ask them to propose other triplets to test what rule the first triplet followed. Most people propose a series of even numbers, such as "8-10-12" and on being told that yes, these numbers also obey the rule, quickly conclude that the rule is "ascending even numbers." In fact, the rule was simply "ascending numbers." Proposing odd numbers would have been more illuminating.

An example of how such reasoning can lead scientists astray was published last year. An experiment had seemed to confirm the Sapir-Whorf hypothesis that language influences perception. It found that people reacted faster when discriminating a green from a blue patch than when discriminating two green patches (of equal dissimilarity) or two blue patches, but that they did so only if the patch was seen by the right visual field, which feeds the brain's left hemisphere, where language resides.

Despite several confirmations by other teams, the result is now known to be a fluke, following a comprehensive series of experiments by Angela Brown, Delwin Lindsey and Kevin Guckes of Ohio State University. Knowing the word for a color difference makes it no quicker to spot.

One of the alarming things about confirmation bias is that it seems to get worse with greater expertise. Lawyers and doctors (but not weather forecasters who get regularly mugged by reality) become more confident in their judgment as they become more senior, requiring less positive evidence to support their views than they need negative evidence to drop them.

The origin of our tendency to confirmation bias is fairly obvious. Our brains were not built to find the truth but to make pragmatic judgments, check them cheaply and win arguments, whether we are in the right or in the wrong.

The first of three columns on the topic of confirmation bias.

If all goes well next month, Curiosity, NASA's latest mission to Mars, will land in the Gale crater, a 3.5-billion-year-old, 96-mile-wide depression near the planet's equator. Out will roll a car-size rover to search for signs of life, among other things. It will drill into rocks and sample the contents, using a mass spectrometer, a gas chromatograph and a laser spectrometer.

In the unlikely event that the project finds evidence of life, then what? In particular, who is in charge of deciding what we should do if we encounter living Martian creatures?

Please note that the chances of Curiosity finding actual microbes look very small. They probably lie deep beneath the surface, out of range of lethal radiation and beyond the reach of the rover's probes, and even then they will be rare, if they exist at all. A new paper, however, hints that there's a chance of finding organic molecules that may be characteristic of life. Alexander Pavlov of NASA and colleagues have calculated that simple organic molecules, such as formaldehyde, could survive as little as 2 inches below the surface of Mars, while in young craters more complex molecules like amino acids could be found at such depths.

But none of this would be actual life.

Even a promising fossil would leave doubts about whether anything still lives on the red planet. So the day when the discovery of Martian life is announced is still a very long way off. But perhaps it's time to start thinking about what should happen on that day.

In some ways it is bound to be an anticlimax. Like the announcement of the Higgs boson last week, however magical the moment may be in historical terms, it will not affect most people's daily lives. We can celebrate, congratulate, revel in the detail and philosophize on the meaning, but earthly life will continue as if little had happened.

Pretty soon, though, a political angle will emerge. For one thing, politicians and journalists from countries other than America will start to grumble that this discovery must "belong" to all humankind and not just to NASA. The U.S. government, despite having forked out all the costs of exploring Mars so far, including the $2.5 billion cost of Curiosity, will probably agree. But who will end up making the key decisions?

The United Nations is almost bound to set up an agency to oversee what experiments are planned, but the U.S. may prefer a different body. Private consortia may conceivably start to plan how to go and retrieve a sample, dreaming of the riches to be garnered from displaying it on Earth. If so, nongovernmental organizations will quickly begin to worry about the safety of such a scheme and to champion the rights of Martian microbes to be conserved and respected in their lairs.

In other words, the discovery of extraterrestrial life would produce some predictably messy earthly responses.

As far as I can discern there has been very little public discussion of these issues. The Outer Space Treaty, opened for signature in 1967 by the U.S., U.K. and Soviet Union and ratified by 100 governments, says that no country can claim political sovereignty over land in outer space. The treaty does not forbid private ownership of land in space, however, and it would be up to terrestrial courts to decide if such claims were recognized. Also NASA has clear policies on how to prevent the contamination of one planet with the life of another.

If we hear a radio signal from an extraterrestrial intelligence, there's also a protocol in place, drawn up by the International Academy of Astronautics and invoking three principles: that the decision on whether to reply should be made by an international body; that it should be sent on behalf of all humankind; and that its content should reflect a broad consensus.

But this is of no relevance to unintelligent Martian microbes. If extraterrestrial life is a mystery, so is the question of what we do when we find it.

It is not yet clear whether the current rage against the banks will do more harm than good: whether we are about to throw the baby of banking as a vital utility out with the bathwater of banking as a wasteful casino. But what is clear is that the current mood of Bankerdämmerung is an opportunity as well as a danger. The fact that so many people agree that some kind of drastic reform is needed, all the way along a spectrum from Milibands to mega-Tories, might just open the window through which far-reaching reform of the financial system enters.

All the actors involved bear some blame. First, investment bankers and the principals in financial companies that cluster around them have trousered an increasing share of the returns from the financial markets, leaving less for their customers and shareholders, while getting "too big to fail", so passing their risks to taxpayers.

Second, regulation has failed. As Niall Ferguson argued in his recent Reith Lectures, the perverse consequences of bad regulation bear more responsibility than deregulation, especially given the lack of banking trouble in lightly regulated Australia and Canada. With a Financial Services Authority handbook that runs to 6,000 pages of rules, evidence of rampant deregulation is hard to see.

Examples of bad regulation are legion: the easily gamed Basle capital rules; the US Congressional mandates that virtually forced mortgage lenders to increase lending to those who could least afford loans; the hyper-regulation of British customers in the name of preventing money laundering, making it far harder to move your account, in stark contrast to the minimal regulation of the cosy Libor-setting cartel (or "cesspit" as the Bank of England's Paul Tucker called it).

Third, central banks have failed. What we might call the Greenspan- King doctrine - that central banks should intervene by cutting interest rates if asset prices fall, but not if they rise thanks to cheap money fuelled by a deliberately undervalued Chinese currency - was merely the latest example of central banks actively, if unwittingly, encouraging volatility.

Enough diagnosis. What is the cure? A change of personnel will not do it. The search for chief executives who are not motivated by greed and for regulators who are sufficiently god-like to know how to design rules that cannot be gamed will never succeed. The truth is, the financial system, like the whole of human society, was not designed in the first place; it evolved. And the answer is to allow a better one to evolve.

My own personal experience reinforces my view here, as I was chairman of Northern Rock when it ran into trouble. During that crisis it quickly became clear that not only did I not fully appreciate the liquidity risks in the markets but nor did far more expert people, including rivals and regulators.

That experience, plus some appreciation of evolutionary biology, makes me suspicious of utopian solutions. Regulating Libor will not prevent a scandal somewhere else; reinventing Glass-Steagall's separation of retail and investment banking would not have prevented the failure of Lehmans or AIG; paying executives in shares rather than cash to lengthen their horizons has been tried and it failed; a culture of compliance can become lethally complacent.

What we need is an evolved, organic, bottom-up system that hands power back to customers and gets innovation working on potential improvements. The way to get that is to open up the banking sector to plentiful competition, dismantling its cosy, crony oligopolistic structure - in which, for example, the biggest customer, the Government, hands the bigger firms handsome income streams from the taxpayer for bond issuance.

So the first task is to tear down the barriers to entry that have prevented the emergence of new clearing banks for decades. Make it much easier not just for the supermarkets' new banks but for mobile phone companies to set up financial services systems as they have so successfully in Africa where few people are trapped in conventional banks. Make it easier for customers to move between banks. Punish size - make regulation fall more heavily, not more lightly, on the biggest companies. And break up the state-owned banks into small units before selling them. Innovation would then follow.

In the future we could open up the world of currencies so that you are neither limited to using pounds nor even to traditional forms of money. Transactions could be in synthetic digital currencies such as mobile phone credits (already big business in Africa) or something yet unheard of. Such ideas about competition between currencies should be encouraged, not stomped on by a jealous state monopoly.

The one politician who is thinking hardest in this way is a radical Tory MP, Douglas Carswell. He points out that Germany has 2,000 banks, most of which are utilities serving local businesses, not casinos serving gamblers. There is nothing inevitable about the concentration of banking into a stodgy oligopoly of banks as in this country - a concentration that has only grown as a result of the crisis, since Barclays now owns Lehmans, Lloyds owns HBOS and Bank of America owns Merrill Lynch.

Mr Carswell would reinvent Glass-Steagall's distinction between investment and retail banking but horizontally within banks rather than vertically between them. Under his system, when you deposit a sum at the bank you would tick one of two boxes. Box 1 would mean the money remains yours and the bank just stores it for you, safely, and probably for a fee.

Box 2 would mean the money would be lent on by the bank in the normal "fractional-reserve" way, with the promise of interest. Only Box 1 money would attract a deposit guarantee from the State.

Who knows how much money each box would attract? The traditional divisions of banks would have to sharpen their act to attract customers. And any institution that could not convince many people to risk their money in this way would automatically have a higher capital ratio. No need for an artificial calculation.

As Adam Smith and Charles Darwin showed, you cannot plan an economy or predetermine innovation any more than Mother Nature can design an ecosystem or a giraffe. These things evolve. So banking reform must concentrate on finding a mechanism to put trial and error to work, not on defining a perfect system that only works with angels in post.

Two rival designs of plant biochemistry compete to dominate the globe. One, called C3 after the number of carbon atoms in the initial sugars it makes, is old, but still dominant. Rice is a C3 plant. The other, called C4, is newer in evolutionary history, and now has about 21% of the photosynthesis "market." Corn is a C4 plant. In hot weather, the C3 mechanism becomes inefficient at grabbing carbon dioxide from the air, but in cool weather C4 stops working altogether. So at first glance it seems as if global warming should benefit C4.

Certainly, in bright sunlight and warm temperatures, C4 plants grow faster than C3 ones and need less nitrogen fertilizer. Under these conditions, a C4 crop like corn or sugar cane can achieve higher yields and tolerate drought better than a C3 crop like wheat or rice. Of the 86 plant species that supply most of the world's food, only a handful are C4, but they dominate tropical agriculture: The chief ones are corn, sugar cane, millet and sorghum.

But it is not quite that simple. Surprisingly, the C4 strategy first became common in the repeated ice ages that began about four million years ago. This was because the ice ages were a very dry time in the tropics and carbon-dioxide levels were very low-about half today's levels. C4 plants are better at scavenging carbon dioxide (the source of carbon for sugars) from the air and waste much less water doing so. In each glacial cold spell, forests gave way to seasonal grasslands on a huge scale. Only about 4% of plant species use C4, but nearly half of all grasses do, and grasses are among the newest kids on the ecological block.

So whereas rising temperatures benefit C4, rising carbon-dioxide levels do not. In fact, C3 plants get a greater boost from high carbon dioxide levels than C4. Nearly 500 separate experiments confirm that if carbon-dioxide levels roughly double from preindustrial levels, rice and wheat yields will be on average 36% and 33% higher, while corn yields will increase by only 24%.

Another complication is that C4 has a larger share of the market in weeds. Of the 18 most pestilential weeds that trouble farmers, 14 are C4. So, all else being equal, and especially in temperate regions where C3 crops dominate, the battle against weeds should get easier as carbon dioxide levels rise-because C3 crops can accelerate their growth more than C4 weeds can.

Last year, Qing Zeng of the Institute of Soil Science in Nanjing and his colleagues published the first test of this prediction on a real farm. By emitting carbon dioxide over plots of rice, they enriched the air to almost twice the ambient level of CO2. They then measured the growth rate of both rice and its worst weed, barnyard grass (a C4 plant), in the experimental plots, compared with control plots nearby.

The ear weight of the rice was enhanced by 37.6% while the growth of the barnyard grass was actually reduced by 47.9%, because the vigorous rice shaded out the weeds. So the good news is that rising carbon-dioxide levels are, on balance, slightly helping crops (mostly C3) compete against weeds (mostly C4) rather than vice versa.

Still, that enormous yield advantage of C4 plants in hot weather suggests an obvious next goal for plant breeders.

Given that most rice grows in hot countries, fiddling with its genes to make it into a C4 plant could boost its yield by 50% and cut its nitrogen needs, transforming world food supply. This is the goal of the C4 Rice Project at the International Rice Research Institute in the Philippines. It takes heart from the fact that C4 "technology" has emerged naturally in many different lines of plants, so why not put it in rice, too?

As I cowered in my parked car in a street in Newcastle last Thursday, nearly deafened by hail on the roof of the car, thunder from the black sky and shrieking girls from the doorway of a school, a dim recollection swam into my mind. After inching back home slowly, through the flooded streets, I googled to refresh the memory. On 23 March this year, the Meteorological Office issued the following prediction:

"The forecast for average UK rainfall slightly favours drier-than-average conditions for April-May-June as a whole, and also slightly favours April being the driest of the 3 months. With this forecast, the water resources situation in southern, eastern and central England is likely to deteriorate further during the April-May-June period."

That went well, didn't it? April-May-June was the wettest ever in England, though not in Britain. According to the private forecaster MeteoGroup, June was probably the wettest in England and Wales since 1860, the dullest since 1909 and the coldest since 1991. The water resources situation, far from deteriorating, is a cup that overfloweth.

The Met Office's track record of short-range (5-day) forecasting is, in my experience, very good and getting better, but its longer-range predictions have often been not just badly wrong, but consistently biased on the warm, dry side.  In 2007, it wrongly forecast a warm summer. In 2008 it wrongly forecast a mild winter. In 2009, it said "the chances of getting the barbecue out are much higher than last year" but the summer was a washout. Also that year it said that the trend towards milder winters was likely to continue, whereupon a savage winter followed.

Chagrined, it said it would give up seasonal forecasting, but continued to produce much the same information in three-month forecasts. In October 2010 it saw "a very much smaller chance of average or below-average temperatures" in the coming winter shortly before the coldest December for 100 years. These mispredictions were not without consequence. The under-preparedness of airports and councils for the big freezes at the beginning and end of 2010 was directly related to the forecasts they had sought.

Now look at the curriculum vitae of the chairman of the Met Office, Mr Robert Napier. He is also chairman of the Green Fiscal Commission and the World Conservation Monitoring Centre, director of the Carbon Disclosure Project, the Alliance of Religions and Conservation and the Climate Group. He is so high up in the church of global warming, he is a carbon cardinal. I am sure he is a man of great integrity, but given this list you have to wonder if one of the organizations he chairs does not occasionally - and perhaps unconsciously - aim to please him with warm long-range forecasts.

Of course, these days the narrative has changed and we are usually told to expect more extreme weather events as a result of climate change, rather than a warming trend per se. If June was indeed the wettest since 1860, that is extreme, but with only a few centuries of data, records are bound to be broken from time to time -- and it is not much of an extreme that fails to beat a 152-year record.

Likewise, in November 2009 when torrential rain swept away the bridge at Workington, a Cumbrian rain gauge recorded the greatest rainfall in any 24 hour period since British records began -- a total of 316mm (12.5in). Astonishing: till you read that it did not break the "day" rainfall record, which is measured from 9am to 9am and which is still held by Martinstown in Dorset on 18 July 1955 - 279mm. That's before global warming was supposed to have shown up.

What, in other words, was so special about the climate in 1860 or 1955 that it too produced extreme events? The truth is that for all the talk of climate change, a trend of half a degree of warming in half a century is still very much less relevant to airports, wedding planners or breeding birds than the random and occasionally extreme variation that is bound to show up in some years with or without man-made climate change. As they say in physics, the noise is greater than the signal. It certainly was last Thursday.

Update 1: The Times pubpished a letter from Bob Ward calling my article "rather silly". Since his letter confirmed the accuracy of my main point -- that no trend can be discerned in the signal --

"While he is right that we cannot yet detect the signal of climate change within the relatively small datasets of extreme weather events in the UK..."

and contradicted no other of my arguments, I thought his letter was "rather silly".

Update 2: Paul Homewood has some good graphs here, showing how trend-free June's weather in England still is.

here is one of his charts.

One of the delights of science is its capacity for showing us that the world is not as it seems. A good example is the startling statistic that there are at least 10 times as many bacterial cells (belonging to up to 1,000 species) in your gut as there are human cells in your entire body: that "you" are actually an entire microbial zoo as well as a person. You are 90% microbes by cell count, though not by volume-a handy reminder of just how small bacteria are.

This fact also provides a glimpse of the symbiotic nature of our relationship with these bugs. A recent study by Howard Ochman at Yale University and colleagues found that each of five great apes has a distinct set of microbes in its gut, wherever it lives. So chimpanzees can be distinguished from human beings by their gut bacteria, which have been co-evolving with their hosts for millions of years.

A new experiment by Hachung Chung in Prof. Dennis Kasper's laboratory at Harvard Medical School shows that this microbial specificity has consequences for health. Researchers bred mice with no gut "flora" at all, then filled their guts with either normal mouse bacteria or normal human bacteria. In both cases the microbes flourished, producing an equal quantity of both individual cells and species.

But the immune system of the mice with human gut flora was markedly less active. In some way, the mouse immune system did not recognize the human gut flora and did not properly develop. When the researchers filled a mouse gut with rat bacteria, the same thing happened: that is, not even the rat bacteria are similar enough to stimulate the mouse immune system. And when the mice with human flora were dosed with salmonella, they contracted a worse infection, their immune system proving less able to respond.

It has been clear for a long time that the microbes in your gut are not just passengers but colleagues that help with the digestion of food: releasing vitamins, breaking down toxins and metabolizing nutrients into more useful forms. What's becoming clear from such experiments is that they are also vital to the immune system's capacity to fight infection. It's as if they train the body's defense forces.

For instance, breast-fed babies, whose gut microbes are dominated by creatures called bifidobacteria, are less likely than formula-fed babies to suffer not only from diarrhea but also from allergies later in life.

The evidence also suggests that the addition of "probiotic" supplements to formula may help the normal development of the immune system.

A recent study by Jeffrey Weiser and colleagues at the University of Pennsylvania found that immune-system cells called neutrophils were less responsive to pathogens in mice that had grown up germ-free or on antibiotics. This may be why people taking long courses of broad-spectrum antibiotics can often get secondary infections.

Our sometimes excessive hygiene may not only affect the body's ability to fight infection when it does come, but may even cause it to turn on itself. There has long been suspicion among medical researchers that the rise of autoimmune disorders such as asthma could be abetted by the sterility of our homes compared with when we lived "wild."

The results of early-phase clinical trials seem to suggest, for example, that the symptoms of multiple sclerosis can be ameliorated by deliberate infection with intestinal worms, such as hookworms or pig whipworms. People with hookworm rarely suffer from allergies or autoimmune problems.

Prof. David Pritchard, of Nottingham University in the U.K., thinks this is because hookworms have an innate ability to moderate the immune system to allow them to survive in the body. This moderating influence may also diminish the self-harming immune response that leads to the symptoms of MS. Worms are parasites, but ones whose presence over the evolutionary eons we may have come to rely on for normal immune function.

These days the heritability of intelligence is not in doubt: Bright adults are more likely to have bright kids. The debate was not always this calm. In the 1970s, suggesting that IQ could be inherited at all was a heresy in academia, punishable by the equivalent of burning at the stake.

More than any other evidence, it was the study of twins that brought about this change. "Born Together-Reared Apart," a new book by Nancy L. Segal about the Minnesota study of Twins Reared Apart (Mistra), narrates the history of the shift. In 1979, Thomas Bouchard of the University of Minnesota came across a newspaper report about a set of Ohio twins, separated at birth, who had been reunited and proved to possess uncannily similar habits. Dr. Bouchard began to collect case histories of twins raised apart and to invite them to Minneapolis for study.

By 1990, he, Dr. Segal and other colleagues were ready to publish their results in Science magazine. By then they had measured the IQ of 48 pairs of monozygotic, or identical, twins, raised apart (MZA) and 40 pairs of such twins raised together (MZT). The MZA twins were 69% similar in IQ, compared with 88% for MZT twins, both far greater resemblances than for any other pairs of individuals, even siblings. Other variables than genetics, such as material possessions in the home, had little influence, nor was the degree of social contact between the twins in each pair associated with their similarity in IQ.

The paper attracted plenty of the usual criticism, and for years there was a quiet whispering campaign to discredit the Mistra study on the grounds that it relied on anecdotes, underestimated contact between twins, ignored a tendency for reunited twins to exaggerate their similarities or assumed too little similarity among the families into which the twins were adopted.

Yet, as Dr. Segal records, the Mistra scientists were meticulous in addressing these issues and more. Too politically incorrect to be funded by most government agencies, the study relied on grants from sources like the Pioneer Fund, once at the forefront of the eugenics movement. What counted, Dr. Bouchard argued, were the results of the research, not the source of the twins' travel expenses.

Today, a third of a century after the study began and with other studies of reunited twins having reached the same conclusion, the numbers are striking. Monozygotic twins raised apart are more similar in IQ (74%) than dizygotic (fraternal) twins raised together (60%) and much more than parent-children pairs (42%); half-siblings (31%); adoptive siblings (29%-34%); virtual twins, or similarly aged but unrelated children raised together (28%); adoptive parent-child pairs (19%) and cousins (15%). Nothing but genes can explain this hierarchy.

But as Drs. Bouchard and Segal have been at pains to point out from the start, this high heritability of intelligence mainly applies to nonpoor families. Raise a child hungry or diseased and environment does indeed affect IQ. Eric Turkheimer and others at the University of Virginia have shown that in the most disadvantaged families, heritability of IQ falls and the influence attributed to the shared family environment rises to 60%.

(Image from Discover magazine)

In other words, hygienic, well-fed life enables people to maximize their genetic potential so that the only variation left is innate. Intelligence becomes significantly more heritable when environmental hurdles to a child's development have been dismantled.

IQ heritability in the middle class proves uncannily similar to the estimate made by the very first study of twins raised apart, by the British psychologist Cyril Burt between 1943 and 1966. He found that the similarity in IQ between MZA twins was 77.1%. The fact that this number did not change as his sample grew to an improbably large size led to charges by the Princeton psychologist Leon Kamin in the 1970s that Dr. Burt (then dead) had committed fraud by making up most of his results. To this day, experts disagree on how many of his data Dr. Burt invented, but his conclusion was not wrong by much.

Part of the preamble to Agenda 21, the action plan that came out of the Rio Earth Summit of 1992, reads: "We are confronted with a perpetuation of disparities between and within nations, a worsening of poverty, hunger, ill health and illiteracy, and the continuing deterioration of the ecosystems on which we depend for our well-being."

In the 20 years since, something embarrassing has happened: a sharp decrease in poverty, hunger, ill health and illiteracy and a marked reduction in these global disparities. The conference that begins next week in Rio de Janeiro, on the 20th anniversary of the first Earth Summit, will nonetheless remain resolutely pessimistic about the planet's ecosystems and their capacity to support human beings indefinitely if economic growth continues. The reasoning has changed over time, however.

[For example, from here: Although world population has increased by about 80% over this time (World Bank 2009), the number of people below the $1 a day poverty line has shrunk by nearly 64%, from 967 million in 1970 to 350 million in 2006. As for inequality, see chart above.]

The original claim, based on the influential 1972 best seller "The Limits to Growth," by the Club of Rome, was that resources would have begun to run out by now. Instead supplies of minerals have increased, thanks to ingenuity, technology and demand.

Later the emphasis shifted to humankind's "ecological footprint," which, it was claimed, was exceeding the planet's carrying capacity. But this, too, took a blow when the most thorough assessment of the world's ecology, by Helmut Haberl of the University of Klagenfurt in Austria, found that people and their domestic animals were eating or damaging just 23.8% of the vegetation growing on land, and that in richer parts of the world they were enhancing the productivity of the remaining vegetation by almost as much through irrigation and fertilizer.

The Riocrats now have a new tack, which will dominate next week's discussion: planetary boundaries. An influential paper in 2009 written by Johan Rockstrom of Stockholm University and 28 colleagues argued that there are nine thresholds, crossing any of which will trigger collapse of the Earth's life support systems: land-use change, loss of biodiversity, nitrogen and phosphorus levels, water use, ocean acidification, climate change, ozone depletion, aerosol loading and chemical pollution.

The trouble with this approach, according to a new report by Linus Blomqvist, Ted Nordhaus and Michael Shellenberger of the Breakthrough Institute in San Francisco, is that, for six of these measures, "there are no global tipping points beyond which these ecological processes will begin to function in fundamentally different ways. Hence the setting of boundaries for these mechanisms is an arbitrary exercise."

A good example is land-use change. The Rockstrom paper suggested that if human beings convert 15% of the land surface of the Earth to cropland, the world will pass a tipping point, because as marginal land gets exhausted, a small increment in food demand would produce an accelerating increase in cultivation. Currently we cultivate about 11.7% of the land. Yet there is no evidence that anything special happens at 15%. In the words of Steve Bass of the International Institute for Environment and Development in London, "If anything, the opposite has probably been more true: Converting land for farming and for industry has clearly delivered a great deal of well-being."

Furthermore, the use of synthetic fertilizer has kept that percentage lower than it would otherwise have been. The independent scholar Indur Goklany argues that, "had global agricultural productivity been frozen at its 1961 level, then the world would have needed over 3,435 million hectares (Mha) of cropland rather than 1,541 Mha actually used to produce as much food as it did in 2002." That saved an area about as large as is set aside for conservation.

The "boundaries" approach needs to incorporate the possibility that, thanks to technology, fossil fuels and minerals, people are already living more lightly on the land than we did in the past.

My latest Mind and Matter column in the Wall Street Journal

After celebrating her 60th year on the throne in style this past week, Britain's Queen Elizabeth II can now look forward to breaking some more records. She is already, at 86, Britain's oldest monarch (were she to die now, her son would immediately be the 12th oldest). On Sept. 10, 2015, she would pass Queen Victoria to become the longest-reigning monarch in British history. To beat Louis XIV (who succeeded to the throne at the age of 4) for the longest reign in European history, she would have to live to 98.

Elizabeth II is still going strong, but the maximum human lifespan isn't rising at anything like the rate of average life expectancy, which is rushing upward globally at the rate of about three months a year, mainly because of progress against premature mortality. Indeed, we may already have hit some kind of limit for maximum lifespan-perhaps because natural selection, with its strict focus on reproductive success, has no particular need to preserve genes that would keep us going to 150.

The oldest woman in the world, Besse Cooper, a retired schoolteacher in Georgia, will be 116 on Aug. 26, according to the Gerontology Research Group, an organization that studies aging issues. That's a great age, but it's a hefty six years short of the record: 122 years and 164 days, set by Jeanne Calment of France in 1997. In other words, if Mrs. Cooper can get there, Mrs. Calment's record will have stood for 21 years; if she can't, maybe longer.

That's a long time, considering that there are now nearly a half million centenarians alive in the world. That number has been going up 7% a year, but the number of those over 115 is not increasing.

If Mrs. Cooper does not take the record, there are only two other 115-year-olds alive to take on the challenge, and one of them is a man: Jiroemon Kimura, a retired postman from Kyoto. He's within seven months of beating the age record for his sex, set by Christian Mortensen, who died in 1998. But Mr. Kimura is less likely than a woman to make 122, and there are fewer women over 115 today (two) than there were in 2006 (four) or even 1997 (three [this should be four]).

At least two people died after their 110th birthdays in the 1800s, if you're willing to trust the birth certificates [No: one of these did not have a birth certificate]. So the increase of 12 years in maximum life expectancy during the 20th century was just one-third as large as the increase in average life expectancy during the period (36 years).

In 2002, James Vaupel of the Max Planck Institute for Demographic Research in Rostock, Germany, startled demographers by pointing out that every estimate published of the level at which average life expectancy would level out has been broken within a few years. Jay Olshansky of the University of Illinois, however, argues that since 1980 this has no longer been true for already-old people in rich countries like the U.S.: Official estimates of remaining years of life for a woman aged 65 should be revised downward.

Thanks to healthier lifestyles, more and more people are surviving into old age. But that is not incompatible with there being a sort of expiration date on human lifespan. Most scientists think the decay of the body by aging is not itself programmed by genes, but the repair mechanisms that delay decay are. In human beings, genes that help keep you alive as a parent or even grandparent have had a selective advantage through helping children thrive, but ones that keep you alive as a great-grandparent-who likely doesn't play much of a role in the well-being and survival of great-grandchildren-have probably never contributed to reproductive success.

In other words, there is perhaps no limit to the number of people who can reach 90 or 100, but getting more than a handful of people past 120 may never be possible, and 150 is probably unattainable, absent genetic engineering-even for a monarch.

Human beings love sharing. We swap, collaborate, care, support, donate, volunteer and generally work for each other. We tend to admire sharing when it's done for free but frown upon it-or consider it a necessary evil-when it's done for profit. Some think that online, we're at the dawn of a golden age of free sharing, the wiki world, in which commerce will be replaced by mass communal sharing-what the futurist John Perry Barlow called "dot communism."

Certainly, in recent years we all rushed to put our reviews on Amazon, our travel experiences on TripAdvisor, our photographs on Flickr, and our innermost secrets on Facebook without expecting to profit from doing so.

But as the float of Facebook shows, commerce still seems alive online. The law professor and economist Thomas Hazlett of George Mason University jokes, "There sure are a lot of billionaires in this new wiki economy."

Facebook's founders, like Google's, once expressed their disdain for profit-motivated sharing. Mark Zuckerberg told the Harvard Crimson in 2004 that he did not create the website with the intention of generating revenue. In the same way, Sergey Brin and Larry Page initially resisted supporting their search engine with advertising: "The issue of advertising causes enough mixed incentives that it is crucial to have a competitive search engine that is transparent and in the academic realm," they wrote in 1998.

This is not necessarily hypocritical. Many entrepreneurs genuinely want to change the world, rather than make a living, and these three were almost certainly no exception. It's just that they discovered that the best way to change the world was to take venture capital, or ad revenue, and then to have an IPO, as a means to sharing the product with as many people as possible. The market is the ultimate "commons" in that it is a forum granting powerful incentives to share.

Just as farmers with privately owned real property grow ever more food so they can share it with others, not to hoard it, so private enterprises in the virtual world share the innovations that allow people to share information. Dr. Hazlett points out that the ultimate sharing forum, the mobile Web (which enabled Web surfing from cellphones), had its first big success in Japan, on a private platform owned by NTT DoCoMo.

Yet online sharing keeps defying the gloomy prophets who have been forecasting the enclosure of the digital commons by selfish landlords, wielding patents, for more than a decade. (Lawrence Lessig's "Code and Other Laws of Cyberspace," written in 1999, was notably pessimistic about the chances of the Web staying open to all.) "From each according to his ability, to each according to his need" has come closer to realization in cyberspace than it ever did in, say, Minsk.

Even profit, once you look at it more closely, seems more like sharing than most people think. After all, the "consumer surplus" of Facebook-the estimated value that people get from using it-is far greater than the firm's profit, while "shares" issued to shareholders make these investors members of the Facebook corporate commons. Says Dr. Hazlett: "Capitalism really knows how to appropriate all the good kumbaya, doesn't it?"

There may be an ancient parallel. The very first hunter-gatherers to start trading (about 120,000 years ago, according to the hazy archeological evidence) probably already had an ethos of communal sharing within the tribe-and an ethos of violent predation of other tribes. That's roughly how chimpanzee society works today. Then they gradually discovered a way to share with other tribes that was mutually beneficial: trade.

When the limitations of barter became too obvious-what the other lot has in surplus may not be what you need right now-a common currency was invented. But that only encouraged sharing through trade. Likewise the monetization of the Internet's sharing ethos will only spread it.

If you write about genetics and evolution, one of the commonest questions you are likely to be asked at public events is whether human evolution has stopped. It is a surprisingly hard question to answer.

I'm tempted to give a flippant response, borrowed from the biologist Richard Dawkins: Since any human trait that increases the number of babies is likely to gain ground through natural selection, we can say with some confidence that incompetence in the use of contraceptives is probably on the rise (though only if those unintended babies themselves thrive enough to breed in turn).

More seriously, infertility treatment is almost certainly leading to an increase in some kinds of infertility. For example, a procedure called "intra-cytoplasmic sperm injection" allows men with immobile sperm to father children. This is an example of the "relaxation" of selection pressures caused by modern medicine. You can now inherit traits that previously prevented human beings from surviving to adulthood, procreating when they got there or caring for children thereafter. So the genetic diversity of the human genome is undoubtedly increasing.

Or it was until recently. Now, thanks to pre-implantation genetic diagnosis, parents can deliberately choose to implant embryos that lack certain deleterious mutations carried in their families, with the result that genes for Tay-Sachs, Huntington's and other diseases are retreating in frequency. The old and overblown worry of the early eugenicists-that "bad" mutations were progressively accumulating in the species-is beginning to be addressed not by stopping people from breeding, but by allowing them to breed, safe in the knowledge that they won't pass on painful conditions.

Still, recent analyses of the human genome reveal a huge number of rare-and thus probably fairly new-mutations. One study, by John Novembre of the University of California, Los Angeles, and his colleagues, looked at 202 genes in 14,002 people and found one genetic variant in somebody every 17 letters of DNA code, much more than expected. "Our results suggest there are many, many places in the genome where one individual, or a few individuals, have something different," said Dr. Novembre.

Another team, led by Joshua Akey of the University of Washington, studied 1,351 people of European and 1,088 of African ancestry, sequencing 15,585 genes and locating more than a half million single-letter DNA variations. People of African descent had twice as many new mutations as people of European descent, or 762 versus 382. Dr. Akey blames the population explosion of the past 5,000 years for this increase. Not only does a larger population allow more variants; it also implies less severe selection against mildly disadvantageous genes.

So we're evolving as a species toward greater individual (rather than racial) genetic diversity. But this isn't what most people mean when they ask if evolution has stopped. Mainly they seem to mean: "Has brain size stopped increasing?" For a process that takes millions of years, any answer about a particular instant in time is close to meaningless. Nonetheless, the short answer is probably "yes."

I say this for two reasons. First, it's clear, from glancing around society, that clever people-who on average have slightly bigger brains-aren't having more babies than less-clever people. Second, the fossil record strongly suggests that our brain size peaked at 1,500 cubic centimeters around 20,000 years ago and has since shrunk to 1,350 cc.

This neither worries nor surprises me. We ceased relying upon individual brain power tens of thousands of years ago. Our civilization now gets all its inventive and creative power from the linking of brains into networks. Our future depends on being clever not individually, but collectively.

This week saw the announcement of the latest conclusions of the Copenhagen Consensus, a project founded by Bjørn Lomborg in which expert economists write detailed papers every four years and then gather to vote on the answer to a simple question: Imagine you had $75 billion to donate to worthwhile causes. What would you do, and where should we start?

This is the third time the consensus has spoken. Though such agreements should always be treated with caution-after all, a consensus of global experts in 1920 would probably have prioritized eugenics-the three pronouncements are remarkable for their consistency and yet also for their capacity to surprise. At the top of the list this year, as in 2008 (it was second only to HIV in 2004), comes the unsexy topic of micronutrients. The smartest way to benefit the most disadvantaged people is to get them vitamins and minerals.

On three different occasions now, three different groups of experts, with no ax to grind and no stake in vitamin firms, have reached the same answer. Enhancing nutrients, they calculate, yields benefits 30 times greater than costs. The readers of Slate magazine, given the chance to vote on the Copenhagen Consensus in recent weeks, mostly agreed-putting micronutrients second only to family planning.

The evidence for micronutrients has been getting stronger. Studies from Guatemala, following up children for 30 years, find that good early nutrition not only combats stunting and increases intelligence but, says Dr. Lomborg, "also translates into higher education and substantially higher (23.8%) incomes in adult life, which not only matters to the individuals but also starts a virtuous circle."

I asked him if he was surprised that micronutrients became the consistent top priority among his experts. He replied: "I'm surprised that we don't hear more about this, and I'm gratified that we got it right, way before it became obvious that it really is one of the best ways forward."

Another person who spotted the importance of micronutrients a long time ago is a Swiss geneticist, Ingo Potrykus. Realizing that insufficient calories was not the only form of malnutrition, he concluded that vitamin A deficiency, for those living on a monotonous diet of rice, was the most tractable of the big problems facing the world. He and Peter Beyer designed a new variety of rice plant that could be given away free to help the poorest people in the world.

Vitamin A deficiency affects the immune system, leading to illness and frequently to blindness. It probably causes more deaths than malaria, HIV or tuberculosis each year, killing as many people as the Fukushima tsunami every single day. It can be solved by eating green vegetables and meat, but for many poor Asians, who can afford only rice, that remains an impossible dream. But "biofortification" with genetically modified plant food (such as golden rice) is 1/10th as costly as dietary supplements.

"Golden rice"-with two extra genes to make beta-carotene, the raw material for vitamin A-was a technical triumph, identical to ordinary rice except in color. Painstaking negotiations led to companies waiving their patent rights so the plant could be grown and regrown free by anybody.

Yet today, 14 years later, it still has not been licensed to growers anywhere in the world. The reason is regulatory red tape deliberately imposed to appease the opponents of genetic modification, which Adrian Dubock, head of the Golden Rice project, describes as "a witch-hunt for suspected theoretical environmental problems ... [because] many activist NGOs thought that genetically engineered crops should be opposed as part of their anti-globalization agenda."

It is surprising to find that an effective solution to the problem consistently rated by experts as the poor world's highest priority has been stubbornly opposed by so many pressure groups supposedly acting on behalf of the poor.

Being maltreated as a child can perhaps affect you for life. It now seems the harm might reach into your very DNA. Two recently published studies found evidence of changes to the genetic material in people with experience of maltreatment. These are the tip of an iceberg of discoveries in the still largely mysterious field of "epigenetic" epidemiology-the alteration of gene expression in ways that affect later health.

According to standard theory, genes aren't supposed to change, so you can pass them on to generations untainted by your own mistakes. It now seems they can at least acquire marks of experience during life, affecting how much they are "expressed."

In one study, Avshalom Caspi, Terrie Moffitt and colleagues at Duke University and King's College London looked at sequences at the tips of chromosomes, known as telomeres, in 2,200 Britons born in 1994-95 and followed since birth. These telomeres contain repetitive sequences of DNA code "letters." The number of repeats shrinks during life in everybody, as a sort of clock for biological aging.

Studies had begun to suggest that psychosocial stress can speed up that clock by eroding telomeres more rapidly, though this research mostly relied on people's recall of maltreatment. Then Stacy Drury and colleagues at Tulane University found shorter telomeres in children who stayed in Bucharest orphanages, compared with those in foster families.

The Duke scientists have measured the effect of exposure to bullying, beating or domestic violence between the mother and her partner on telomere length between the ages of 5 and 10. Because blood samples had been taken from the Britons throughout life, it was possible to compare telomere length before and after the violence was experienced. On average, the telomeres did shrink faster in those that experienced violence than in other children.

But in some individuals they actually grew longer, so the mystery of telomeres only deepens. The next step, Dr. Moffitt told me, is to assess subjects' later health by measuring such things as memory changes, inflammation, immune function, even tooth decay. She adds: "So wish us luck!"

Another study, published earlier this year by Audrey Tyrka of Butler Hospital, Providence, R.I., and others found that the loss of a parent or maltreatment as a child resulted in greater "methylation" of some spots near a gene tied to stress response in adulthood. Methylation, the addition of a methyl group of atoms to one DNA "letter," tends to reduce the activity of nearby genes. The implication of the Butler study is that adults who recall maltreatment as children may have reduced activity of a key gene in the system that responds to the stress hormone cortisol. This may be linked to increased anxiety or depression.

These are early days in the study of epigenetics. Scientists are like people finding coins under lampposts but not knowing how many coins remain in the dark. Although the "methylome"-a complete map of where methylation happens in the genome-is being talked of, others caution that we still have almost no idea of both the causes and effects of most such changes, let alone other epigenetic effects like histone modification.

But supposing it does become possible to link bad early experience with bad later health, what then? Epigenetics demolishes the old-and always misleading-distinction between deterministic genes and a manipulable environment. To have your fate determined by your early experiences is not much different from having it determined by your genes, and when experience acts by changing genes, the distinction vanishes.

Yet fortunately, given medical advances, genetic determinism is not necessarily a life sentence, as those who wear glasses for shortsightedness or take growth hormone for growth problems can attest. The same will almost certainly be true for epigenetic determinism: Understanding the mechanism should bring forward possible cures.

Peter Pringle's new book "Experiment Eleven" documents a shocking scandal in the history of medicine, when Albert Schatz, the discoverer of streptomycin, was deprived of the credit and the Nobel Prize by his ambitious boss, Selman Waksman. Streptomycin was and is a miraculous cure for tuberculosis.

Yet the near disappearance of tuberculosis from the Western world, where it was once the greatest killer of all, owes little to streptomycin. Mortality from TB had already fallen by 75% in most Western countries by 1950, when streptomycin became available, and the rate of fall was little different before and after. Scarlet fever, pneumonia and diphtheria all declined rapidly long before their cures were introduced.

Surprisingly, there is still disagreement about why so many infectious diseases retreated in America and Europe after 1800. A medical historian named Thomas McKeown made his name in the 1970s with a book arguing that not only could medicine take little credit until very late in the story (smallpox vaccination aside), but that even sanitation played a small part before about 1900. Instead, he claimed, better nutrition, caused by better farming practices, was the chief cause of better disease resistance.

McKeown's thesis produced a strong reaction from those who thought his aim was political-to rebalance modern health-care from cure to prevention-and that he had missed statistical quirks, like the stagnation of the trend toward less disease at a time when urban populations were booming. For example, the period 1830-1870 in Britain saw few improvements in mortality, despite rising living standards. Living in cities certainly encouraged waterborne diseases like typhoid and cholera that had rarely been a problem in even the poorest villages. Public sanitation eventually did much to change this.

The urban boom also gives a clue to TB's rise and fall. By all accounts, TB was not such a big killer in medieval times, when people stayed in their small villages. It was urban crowding that made the bacterium so successful and so virulent. In the latter part of the 19th century, many of the urban poor either shared beds, or took different shifts in the same bed. Though this had happened before in the countryside, in the cities people were on the move, coming into contact with new room-sharers. It was neither hygiene nor nutrition that defeated TB (though both helped) so much as better housing.

It also helped that after 1900 TB patients were often isolated in sanatoria and that after 1950 people could be cured. All these factors led to a fall in the "effective contact number" per infected individual, from over 20 in 1900 to under one today. The bacterium's opportunities to jump to a new victim grew fewer and fewer.

Does this mean that, in political terms, you can arguably score the defeat of tuberculosis for the private sector, through the improvement in housing caused by economic growth, just as you can score the defeat of, say, cholera for the public sector, through the building of sewers? Surely, it's less straightforward than that: Government drove a lot of slum clearance, while taxes generated by private wealth paid for sewers, vaccines and antibiotics.

With recent rapid economic growth in India, TB incidence has halved since 1990. In Africa, too, it's now falling slowly, albeit after peaking at high levels. Drug resistance may slow the decline but economic growth should mean it does not reverse.

There is another lesson: TB is unlikely to return in the West. Resistance to streptomycin is spreading, but while that might make some cases incurable, the economic and social conditions for TB to spread no longer exist. America saw its lowest- ever incidence (3.6 per 100,000) in 2010.

Here's the graph for Africa and South Asia:

My latest Wall Street Journal column is on the technology of fly fishing rods

Moore's Law is the leitmotif of the modern age: Incessant improvements in communication and computing are accompanied by incessant drops in price. Yet some quite low-tech devices are also experiencing Moore's Laws of their own, especially those that use new materials. Even something as mundane as fishing rods.

Innovation in fishing rods requires no government program nor even results: Productivity is not really a fly-fisherman's goal. Instead, neophilia is the driving force. The avid fly-fisher arrives at a riverbank and finds his friend has brought a slender wisp of carbon fiber that's newer, lighter and more sensitive than his, with a cooler color, so he experiences an unquenchable thirst to spend money. (It's usually a "he.")

Recently, the venerable firm Hardy of Alnwick, England-famous for more than a century for its elegant fishing reels but generally considered the maker of old-fashioned or overpriced rods-has launched a line of rods that has taken the fly-fishing world by surprise. Made from "sintrix" (for silica nano matrix), they are as much as 30% lighter and 60% stronger than existing carbon-fiber rods, the company says. But they are not cheap yet: A typical sintrix rod will set you back $700. Earlier this month, one of the new Hardy rods won a competition organized by the Yellowstone Angler, a famous tackle shop, for the second year running.

Fly rods-whose look falls somewhere between a stick and long whip-aspire to an almost impossible combination of stiffness, flexibility and strength. A 15th-century German treatise shows how hard this was to achieve with natural materials: a slender blackthorn or medlar shoot was fixed to a tapering ash or willow stick after months of curing, drying and heating. By the 19th century, fishermen were using lancewood, bamboo and whalebone rods, soon joined by "greenheart" wood from a South American hardwood tree. Then came "split cane"-a bundle of slender fibers of bamboo, bound to make a whippy but strong rod-that dominated design until the 1970s, fighting off the challenge of glass fiber.

Then, as with oars and golf clubs, split cane quickly gave way to carbon fiber, made from polymers that have been stretched, oxidized and heated until all that's left is ribbons of mostly graphite glued together with resin. The fibers are amorphous, meaning that, although mostly parallel with the length of the rod, they twist and double back on each other.

Other sporting objects like baseball bats are being transformed by carbon nanotubes, molecular cylinders of carbon atoms that are among the strongest materials yet known, capable of enduring the tension of a weight of 11 tons on a cable with a millimeter-square cross section. But they're too inconsistent and stiff for a fly rod, Hardy concluded.

When Richard Maudslay, descendant of the inventor of the lathe, became chairman of Hardy after a career in power engineering, he brought the idea of "finite element analysis," a mathematical tool that simulates stresses in materials so that new ideas can be quickly tested. Until then, innovation in fishing rods consisted in asking expert fishermen what they wanted next.

Norman Fleck of Cambridge University used the finite-element method to determine that what was needed was material with better properties in compression. Working with 3M, Hardy tried impregnating the resin with 100-nanometer silica spheres, in effect lubricating the carbon fibers with minuscule bearings. The result was a spectacular combination of strength to resist a big fish and flexibility to whip a length of line out to land softly on the water.

Science has moved on, and nanoparticles as small as 2 nanometers are now in use, so Mr. Maudslay wants to do it again. He argues that improvements in materials, from steel to plastics to silicon, are the keys to understanding the industrial revolution. Fixated by bits and bytes, we sometimes forget the importance of innovation in "stuff."

Generally, junior professors write long and unsolicited emails to senior professors, who reply with short ones after a delay; the juniors then reply quickly and at length. This is not because the seniors are busier, for they, too, write longer and more punctually when addressing their deans and funders, who reply more briefly and tardily. The asymmetry in length and speed of reply correlates with dominance.

When a subordinate chimpanzee grooms a dominant one, it often does so for a long time and unsolicited. When it then requests to be groomed in turn, it receives only a brief grooming and usually after having to ask a second time.

This gorgeous little juxtaposition of tales comes from a new book by Dario Maestripieri of the University of Chicago, who is both a professor and a primatologist (and a primate). His book, called "Games Primates Play," is devoted to ramming home a lesson that we all seem very reluctant to learn: that much of our behavior, however steeped in technology, is entirely predictable to primatologists.

He observes two university colleagues in a coffee shop and notes how the senior one takes the chair with the back to the wall (the better to spot attacks by rivals or leopards), is less attentive to her colleague's remarks than vice versa, stares down her colleague when a contentious issue comes up and takes the lead on walking out the door at the end-all of it neatly corresponding to the behavior of two baboons when one is dominant.

(A new member of a committee on which I served once asked me why a senior colleague was being so horrible to him. I replied: "Oh, it's because when a new male baboon joins a troop, it's traditional for the alpha male to beat him up before becoming his best friend-soon he'll think the world of you." I was right.)

Dr. Maestripieri's most intriguing chapter is entitled "Cooperate in the Spotlight, Compete in the Dark." He describes how people, like monkeys, can be angels of generosity when all eyes are on them, but devils of spite in private. Famously, the citizens of New York City turned to crime when the lights went out in the blackout of July 13, 1977-not because they were evil but because the cost-benefit calculus was altered by the darkness.

Dr. Maestripieri then offers a fascinating analysis of the conundrum of peer review in science. Peer review is asymmetric: The author's name is known, but the reviewers remain anonymous. This is to prevent reciprocal cooperation (or "pal review"): I'll be nice about your paper if you're nice about mine.

In this it partly works, though academics often drop private hints to each other to show that they have done review favors. But peer review is plagued by the opposite problem-spiteful criticism to prevent competitors from getting funded or published. Like criminals in a blackout, anonymous reviewers, in the book's words, "loot the intellectual property of the authors whose work they review" (by delaying publication while pinching the ideas for their own projects) and "damage or destroy the reviewed authors' property" (by denying their competitors grants and publications).

Studies show that peer reviewers are motivated by tribal as well as individual rivalry. Says Dr. Maestripieri: "I am a Monkey-Man, and when I submit a grant application for peer review, I am terrified that it might fall into the hands of the Rat-People. They want to exterminate all of us…(because our animals are cooler than theirs)."

His answer (and it applies to far more fields than science) is total transparency with the help of the Internet. The more light you shine, the less crime primates commit. Once everybody can see who's reviewing whose papers and grant applications, then not only will spite decline, but so will nepotism and reciprocity. Anonymity alters the cost-benefit balance in favor of competition; transparency alters it in favor of cooperation.

It is now official: drilling for shale gas by fracturing rock with water may rattle the odd teacup, but is highly unlikely to cause damaging earthquakes. That much has been obvious to anybody who has followed the development of the shale gas industry in America over the past ten years. More than 25,000 wells drilled have caused a handful of micro-seismic events that can barely be felt.

The two rumbles that resulted from drilling a well near Blackpool last year were tiny. To call a two-magnitude tremor an earthquake is a bit like calling a hazelnut lunch. Such tremors happen naturally more than 15 times a year but go unnoticed and they are a common consequence of many other forms of underground work such as coalmining and geothermal drilling. Earthquakes caused by hydroelectric projects, in which dams load the crust and lubricate faults, can be much greater and more damaging. The Sichuan earthquake that killed 90,000 in 2008 was probably caused by a dam.

So can we now get on and start a home-grown shale gas industry? The economic and environmental benefits could be vast. Just consider the effect that shale gas has had in the US. It has lowered the price of gas to a quarter of that in Europe, thus slashing the cost of energy, reviving manufacturing, creating jobs, halting the expansion of expensive nuclear power and cutting carbon emissions.

The Harvard School of Engineering and Applied Science concluded in February that the surprise fall in America's carbon emissions - by 7 per cent in 2009, probably more since - was caused largely by a switch from coal to shale gas. "A slight shift in the relative prices of coal and natural gas can result in a sharp drop in carbon emissions," according to Professor Michael McElroy, who led the study. All over America coal and nuclear projects are being cancelled or mothballed because of cheap gas. (Declaration of non-interest: I have interests in coalmining; so shale gas is bad news for me, but good news for the country and the planet.) Yet listening to the debate in Britain about "fracking", you would think that we were in a different universe. Tony Juniper, the BBC's favourite green, was arguing yesterday that shale gas might increase carbon emissions because of leakage of methane into the atmosphere. His evidence? A study by Cornell University that has been discredited. Not only was the study partly funded by an anti-fracking pressure group called the Park Foundation but it also made a series of elementary howlers, such as using a cherry-picked short time frame because methane does not stay in the air for long and mistaking Russian theft of gas from pipelines for leakage.

Besides, the proof of the pudding is in the data: shale gas has already cut carbon emissions in a way that wind, biomass and solar power have failed to do. Wind still produces less than 0.5 per cent of all energy and has displaced no fossil fuels. Biomass has been shown to increase carbon emissions, by encouraging deforestation. And solar power, for all its local promise in desert countries, is still an irrelevance globally and a boondoggle nationally.

What about groundwater contamination? This too is mostly hogwash. Since there is usually a mile of rock between aquifers and where the fracking happens, contamination from fracking is highly implausible. More than 25,000 wells have been sunk and there has only been a handful of potential contamination events, most of which proved to be natural. Of course, failure of the well casing or surface chemical spills can happen occasionally, as in any industry. But the chemicals used in fracking - less than 0.5 per cent of the solution used to displace the gas - are ordinary chemicals of the kind that you find under your kitchen sink: disinfectants, surfactants and the like.

The campaign to stop shale gas proving its case in the market is political, not scientific. Behind it lies vested interests. The Russian gas industry, which is alarmed at losing its impending near-monopoly on European gas supplies, has been vocal in its criticism of shale gas. The coal and nuclear industries too would like to see this baby strangled at birth, but have been less high-profile.

Most of the opposition, though, has come from those with a vested interest in renewable energy, including the big environmental pressure groups, which are alarmed that the rich subsidies paid to wind, biomass and solar may be under threat if gas gets too cheap and cuts carbon emissions too effectively. Their entire rationale for subsidy, parroted by their dutiful poodle Chris Huhne, when Energy Secretary, is that gas would get more expensive until even wind and solar looked cheap. That was wishful thinking.

Even if you do not think carbon emissions are the highest environmental priority, there is a more fundamental reason why using gas is good for the planet. No other species needs or uses it. Every time you grow a biofuel crop, harvest timber for a biomass power station, pave a desert with solar panels or dam a river for a hydro plant, you are stealing energy from the natural world. Even the wind is needed - by eagles for soaring, by bats for feeding (both are regularly killed by wind turbines). As the only species that uses gas, the more we use it the more we can leave other sources of energy for nature.

April 25 is World Malaria Day, designed to draw attention to the planet's biggest infectious killer. The news is generally good. Never has malaria, which is carried by the Anopheles mosquito, been in more rapid retreat. Deaths are down by a third in Africa over the past decade alone, and malaria has vanished from much of the world, including the U.S.

As so often happens in the battle against disease, however, evolution aids the enemy. The selection pressure on pathogens to develop resistance to new drugs is huge. In recent weeks, the emergence on the Thai-Myanmar border of malaria strains resistant to artemisin, a plant-derived drug, have led to pessimistic headlines and reminders of the setback caused by resistance to the drug chloroquine, which began in the 1950s.

For this reason, prevention generally works better than cure in eradicating infectious diseases: Vaccination beat smallpox, clean water beats cholera, less crowded living beats tuberculosis and protection from mosquitoes beats malaria. Good prevention keeps bad evolution from getting started. Yet two can play at evolution. The newest weapon in the fight against mosquitoes ingeniously turns the evolutionary tables on the pests.

The mosquito Aedes aegypti lives almost exclusively in human settlements, breeding in small pools inside discarded objects like car tires and coconut husks. Dengue fever, which it carries, now infects at least 50 million people a year and rising. Both Aedes and dengue have evolved to exploit dense urban settlements.

Yet this also makes the mosquito vulnerable to a new control technique developed by a former Oxford University scientist named Luke Alphey. He genetically modified mosquitoes so that they would produce no viable progeny unless supplied with a dietary supplement. His idea was to release the modified males (only the females bite humans) and let them mate with wild females, whose offspring would then die. He can also make females genetically flightless or doomed to die young.

A similar technique eradicated the screw worm (a blowfly maggot that infects livestock) from North and Central America. Gamma rays made male flies sterile but didn't affect their ability to mate, and since females only mate once, this led to an epidemic of infertility in wild flies. The beauty of this technique is that it generates the opposite of diminishing returns: The rarer the pest gets, the more likely it is that the released males will mate with the few remaining females.

But gamma rays damage mosquitoes too much, so a subtler, gene-based form of sterilization was needed. Enter Dr. Alphey and his company Oxitec, which last year announced the results of a trial of his technique in the Cayman Islands, showing that released male Aedes mosquitoes did indeed succeed in mating with wild females. Further tests are planned for Key West, Fla., and other areas before moving into larger cities.

Predictably, perhaps, the genetic modifications have led to objections from some Western pressure groups, showing their now customary tendency to elevate theoretical principles above the battle against human suffering. Yet the great advantage of Dr. Alphey's approach, in contrast to the fogging of dengue-affected areas with insecticide, is that it is pest-specific. No other insect is hurt.

It will work best for a mosquito like Aedes that breeds in modest numbers and only in urban refuse. Common Culex mosquitoes, which also breed in ditches, sewage systems and rural habitats, may be too widespread to be controlled this way. But there is another fastidious mosquito genus that prefers small pools close to human habitation and that could also be vulnerable to a campaign of genetic sterilization: Anopheles, the carrier of malaria. With such a technique, the eventual eradication of human malaria from the planet is far from being an impossible dream.

The actual paper will appear in Current Biology, but this is from the press release from James Cook University (I hate it when scientists announce their results by press release before the journal article is available).

Update: here's the article in press, but behind a paywall.

Quoting one of the authors, Terry Hughes:

"This study has given us a more detailed understanding of the sorts of changes that could take place as the world's oceans gradually warm and acidify.

"And it has increased our optimism about the ability of coral reef systems to respond to the sorts of changes they are likely to experience under foreseeable climate change."

The good news from the research, says Professor Hughes, is that complete reef wipeouts appear unlikely due to temperature and pH alone.

"However, in many parts of the world, coral reefs are also threatened by much more local impacts, especially by pollution and over-fishing. We need to address all of the threats, including climate change, to give coral reefs a fighting chance for the future."

The press release gives more details of the study:

They identified and measured a total of 35,428 coral colonies on 33 reefs from north to south. Studying corals on both the crests and slopes of the reef, they found that as one species decreases in abundance, another tends to increase, and that species wax and wane largely independently of each other.

And:

"We chose the iconic Great Barrier Reef because water temperature varies by 8-9 degrees along its full length from summer to winter, and because there are wide local variations in pH. In other words, its natural gradients encompass the sorts of conditions that will apply several decades from now under business-as-usual greenhouse gas emissions.

This is a point that I have been emphasising recently: that natural variation in ocean pH is already greater than any future trend likely from carbon emissions.

In her remarkable new book "The Rambunctious Garden," Emma Marris explores a paradox that is increasingly vexing the science of ecology, namely that the only way to have a pristine wilderness is to manage it intensively. Left unmanaged, a natural habitat will become dominated by certain species, often invasive aliens introduced by human beings. "A historically faithful ecosystem is necessarily a heavily managed ecosystem," she writes. "The ecosystems that look the most pristine are perhaps the least likely to be truly wild."

In the Netherlands, for example, cattle are being used to re-create a simulacrum of a Pleistocene woodland, because their aurochs ancestors would have been vital in keeping forest patchy. To keep African national parks from deforestation, elephant control is sometimes needed. To let aspen, willow and beaver return to Yellowstone, it was necessary to reintroduce the wolf, which reduced elk numbers. To preserve Mojave Desert tortoises, it is essential to control native ravens, whose numbers have been boosted by distant landfill sites.

Some ecosystems are enriched and made more productive by invasive species. In terms of "ecosystem services"-the provision of clean water, the absorption of carbon, the creation of soil, the prevention of erosion-Hawaiian forests dominated by alien tree species can perform better than the pristine habitats they replace. Though many invasive aliens are notorious for the harm they bring (pythons in Florida, cane toads in Australia, brown tree snakes in Guam), many others enhance the local nature scene.

Where I live, in the U.K., American gray squirrels are exterminating native red squirrels with the help of a parapox virus and a better ability to digest acorns. Aesthetically, this is a pity: The red is nicer to look at and part of local culture. But ecologically, one has to admit that the gray is better at filling the squirrel niche in our broadleaf woodland. Reds are really a pine-adapted species that had responded to a broadleaf vacancy after the most recent ice age.

Ms. Marris's book goes further, challenging the very idea of a balance of nature. In the first half of the 20th century, ecologists came to believe in equilibrium-that natural systems tended toward a steady state. So, for example, a bare patch of ground would be colonized by a succession of species-annual weeds, then grasses, then shrubs, then trees-until it reached its "climax" state. Conservation, therefore, was a matter of restoring this climax.

Academic ecologists have abandoned such a static way of thinking for something much more dynamic. For a start, they now appreciate that climate has always changed, and with it, ecology. Twenty thousand years ago the spot where I live was under a mile of ice. Then it was tundra, then birch forest, then pine forest, then alder, linden, elm and ash, then most recently oak, but beech was coming.

Which is its climax? We now know that oak seedlings rarely thrive under mature oaks (which rain caterpillars on them), so the oak climax was just a passing phase.

Yet even as academic ecologists have abandoned balance-of-nature thinking, it still dominates practical conservation management. Ms. Marris quotes the ecologist Daniel Botkin: "If you ask an ecologist if nature never changes, he will almost always say no. But if you ask that same ecologist to design a policy, it is almost always a balance-of-nature policy": preserve this rare species, maintain this habitat structure, freeze in time this ecological moment, return this degraded land to a particular state, whatever the weather and whatever the novel arrivals of exotic species. Just as in our management of the economy, we think of states, not processes.

So what's a good conservationist to do? Ms. Marris sets you free: "In a nutshell: Give up romantic notions of a stable Eden, be honest about goals and costs, keep land from mindless development and try just about everything."

"The world has never been a better place to live in," says science writer Matt Ridley, "and it will keep on getting better." Today, in a world gripped by global economic crisis and afflicted with poverty, disease, and war, them's fightin' words in some quarters. Ridley's critics have called him a "denialist" and "shameful" and have accused him of "playing fast and loose with the truth" for his views on climate change and the free market.

Yet Ridley, 54, author most recently of The Rational Optimist, sticks to his guns. "It is not insane to believe in a happy future for people and the planet," he says. Ridley, who's been a foreign correspondent, a zoologist, an economist, and a financier, brings a broad perspective to his sunny outlook. "People say I'm bonkers to claim the world will go on getting better, yet I can't stop myself," he says. Read on to see how Ridley makes his case. Brilliant or bonkers? You decide.

1. We're better off now

Compared with 50 years ago, when I was just four years old, the average human now earns nearly three times as much money (corrected for inflation), eats one third more calories, buries two thirds fewer children, and can expect to live one third longer. In fact, it's hard to find any region of the world that's worse off now than it was then, even though the global population has more than doubled over that period.

2. Urban living is a good thing

City dwellers take up less space, use less energy, and have less impact on natural ecosystems than country dwellers. The world's cities now contain over half its people, but they occupy less than 3 percent of its land area. Urban growth may disgust environmentalists, but living in the country is not the best way to care for the earth. The best thing we can do for the planet is build more skyscrapers.

3. Poverty is nose-diving

The rich get richer, but the poor do even better. Between 1980 and 2000, the poor doubled their consumption. The Chinese are ten times richer and live about 25 years longer than they did 50 years ago. Nigerians are twice as rich and live nine more years. The percentage of the world's people living in absolute poverty has dropped by over half. The United Nations estimates that poverty was reduced more in the past 50 years than in the previous 500.

4. The important stuff costs less

One reason we are richer, healthier, taller, cleverer, longer-lived, and freer than ever before is that the four most basic human needs-food, clothing, fuel, and shelter-have grown markedly cheaper. Take one example: In 1800, a candle providing one hour's light cost six hours' work. In the 1880s, the same light from a kerosene lamp took 15 minutes' work to pay for. In 1950, it was eight seconds. Today, it's half a second. In these terms, we are 43,200 times better off than in 1800.

5. The environment is better than you think

In the United States, rivers, lakes, seas, and air are getting cleaner all the time. A car today emits less pollution traveling at full speed than a parked car did from leaks in 1970.

6. Shopping fuels innovation

Even allowing for the many people who still live in abject poverty, our own generation has access to more calories, watts, horsepower, gigabytes, megahertz, square feet, air miles, food per acre, miles per gallon, and, of course, money than any who lived before us. This will continue as long as we use these things to make other things. The more we specialize and exchange, the better off we'll be.

7. Global trade enriches our lives

By 9 a.m., I have shaved with an American razor, eaten bread made with French wheat and spread with New Zealand butter and Spanish marmalade, brewed tea from Sri Lanka, dressed in clothes made from Indian cotton and Australian wool, put on shoes of Chinese leather and Malaysian rubber, and read a newspaper printed on Finnish paper with Chinese ink. I have consumed minuscule fractions of the productive labor of hundreds of people. This is the magic of trade and specialization. Self-sufficiency is poverty.

8. More farm production = more wilderness

While world population has increased more than fourfold since 1900, other things have increased, too-the area of crops by 30 percent, harvests by 600 percent. At the same time, more than two billion acres of "secondary" tropical forest are now regrowing since farmers left them to head for cities, and it is already rich in biodiversity. In fact, I will make an outrageous prediction: The world will feed itself to a higher and higher standard throughout this century without plowing any new land.

9. The good old days weren't

Some people argue that in the past there was a simplicity, tranquillity, sociability, and spirituality that's now been lost. This rose-tinted nostalgia is generally confined to the wealthy. It's easier to wax elegiac for the life of a pioneer when you don't have to use an outhouse. The biggest-ever experiment in back-to-the-land hippie lifestyle is now known as the Dark Ages.

10. Population growth is not a threat

Although the world population is growing, the rate of increase has been falling for 50 years. Across the globe, national birth rates are lower now than in 1960, and in the less developed world, the birth rate has approximately halved. This is happening despite people living longer and infant-mortality rates dropping. According to an estimate from the United Nations, population will start falling once it peaks at 9.2 billion in 2075-so there is every prospect of feeding the world forever. After all, there are already seven billion people on earth, and they are eating better and better every decade.

11. Oil is not running out

In 1970, there were 550 billion barrels of oil reserves in the world, and in the 20 years that followed, the world used 600 billion.

So by 1990, reserves should have been overdrawn by 50 billion barrels. Instead, they amounted to 900 billion-not counting tar sands and oil shale that between them contain about 20 times the proven reserves of Saudi Arabia. Oil, coal, and gas are finite, but they will last for decades, perhaps centuries, and people will find alternatives long before they run out.

12. We are the luckiest generation

This generation has experienced more peace, freedom, leisure time, education, medicine, and travel than any in history. Yet it laps up gloom at every opportunity. Consumers do not celebrate their wonderful field of choice and, according to psychologists, say they are "overwhelmed." When I go to my local superstore, I do not see people driven to misery by the impossibility of choice. I see people choosing.

13. Storms are not getting worse

Not at all. While the climate warmed slightly last century, the incidence of hurricanes and cyclones fell. Since the 1920s, the global annual death rate from weather-related natural disasters (that is, the proportion of the world's population killed rather than simply the overall number) has declined by a staggering 99 percent.

The killing power of hurricanes depends more on wealth than on wind speed. A big hurricane struck the well-prepared Yucatán in Mexico in 2007 and killed nobody. A similar storm struck impoverished Burma the next year and killed 200,000. The best defenses against disaster are prosperity and freedom.

14. Great ideas keep coming

The more we prosper, the more we can prosper. The more we invent, the more inventions become possible. The world of things is often subject to diminishing returns. The world of ideas is not: The ever-increasing exchange of ideas causes the ever-increasing rate of innovation in the modern world. There isn't even a theoretical possibility of exhausting our supply of ideas, discoveries, and inventions.

15. We can solve all our problems

If you say the world will go on getting better, you are considered mad. If you say catastrophe is imminent, you may expect the Nobel Peace Prize. Bookshops groan with pessimism; airwaves are crammed with doom. I cannot recall a time when I was not being told by somebody that the world could survive only if it abandoned economic growth. But the world will not continue as it is. The human race has become a problem-solving machine: It solves those problems by changing its ways. The real danger comes from slowing change.

16. This depression is not depressing

The Great Depression of the 1930s was just a dip in the upward slope of human living standards. By 1939, even the worst-affected countries, America and Germany, were richer than they'd been in 1930. All sorts of new products and industries were born during the Depression. So growth will resume unless prevented by wrong policies. Someone, somewhere, is tweaking a piece of software, testing a new material, or transferring the gene that will make life easier or more fun.

17. Optimists are right

For 200 years, pessimists have had all the headlines-even though optimists have far more often been right. There is immense vested interest in pessimism. No charity ever raised money by saying things are getting better. No journalist ever got the front page writing a story about how disaster was now less likely. Pressure groups and their customers in the media search even the most cheerful statistics for glimmers of doom. Don't be browbeaten-dare to be an optimist!

Scientists, it's said, behave more like lawyers than philosophers. They do not so much test their theories as prosecute their cases, seeking supportive evidence and ignoring data that do not fit-a failing known as confirmation bias. They then accuse their opponents of doing the same thing. This is what makes debates over nature and nurture, dietary fat and climate change so polarized.

But just because the prosecutor is biased in favor of his case does not mean the defendant is innocent. Sometimes biased advocates are right. An example of this phenomenon is now being played out in geology over the controversial idea that a meteorite or comet hit the earth 12,900 years ago and cooled the climate.

That the climate suddenly cooled then, plunging the Northern Hemisphere back into an ice age for 1,300 years, is not in doubt. The episode is known as the Younger Dryas, because in Scandinavia abundant pollen from a tundra flower called the mountain avens, Dryas octopetala, reappears in soil from this date, indicating that the forest had once more given way to tundra. With the sudden arrival of cooler, drier and less predictable seasons, early human attempts at agriculture in the Near East ceased, and people returned to nomadic hunting and gathering.

The cause of this cold lurch was seemingly settled some time ago when Wallace Broecker, a Columbia University geochemist, suggested that a North American ice sheet collapsed, flooding the Atlantic with fresh water, which interrupted the normal circulation of the Gulf Stream. Then a marine geologist, James Kennett of the University of California, Santa Barbara, said he had found evidence of the impact of a large object from space 12,900 years ago, in the form of carbon spherules in silt.

Dr. Kennett's argument is that a swarm of meteorites punched through the atmosphere and caused a vast conflagration, filling the air with dust and soot. This shut out the sun, causing decades of continuous winter -sufficient to trigger an advance of ice sheets that, even when the dust cleared, kept the climate cool for more than a thousand years, at least in the Northern Hemisphere.

Dr. Kennett prosecuted his case with gusto, also suggesting that the impact had extinguished North American mammoths, just as an earlier impact had finished off the dinosaurs (a theory hard to reconcile with the survival of mammoths for thousands of years longer on islands off Siberia and Alaska, where hunters could not reach them). He suffered a key setback in recent years when several groups failed to find the right kinds of spherules or otherwise duplicate the results of his team's work-and, worse, when a spherule sample from Younger Dryas rocks proved to be only 135 years old.

But spherules, dated to the right period, now have apparently shown up. Dr. Kennett and colleagues have published evidence in the prestigious Proceedings of the National Academy of Sciences that a "black mat" from the sediment of a Mexican lake dates to 12,900 years ago and shows a sudden peak of magnetic and carbon spherules, "nanodiamonds" of a kind known as lonsdaleite, and charcoal: all of it evidence of extreme heat.

Last year Michael Higgins of the University of Quebec published details of an underwater crater in the Gulf of St. Lawrence, arguing that it may also date from as little as 12,900 years ago. The crater, three miles across, has the characteristic central mound of a fresh meteorite impact. Its meteorite was probably too small to shift the climate, but perhaps it was part of a swarm.

After the previous debacles, the jury will take much convincing that the new results can be replicated. But the burden of proof has shifted a little in Dr. Kennett's favor. After all, Dr. Broecker and his followers, too, may be emotionally invested in his ice-sheet theory: Confirmation bias can affect us all.

Looking past the title ("Parametric Estimations of the World Distribution of Income"), an interesting NBER paper from Maxim Pinkovskiy and Xavier Sala-i-Martin shows that in spite of an 80% increase in population between 1970 and 2006, poverty rates have fallen by the same amount -  80%.

While the paper isn't available online without a fee, in a blog post for VoxEU, the authors feature some of their primary findings and graphs. They write:

World poverty is falling. This column presents new estimates of the world's income distribution and suggests that world poverty is disappearing faster than previously thought. From 1970 to 2006, poverty fell by 86% in South Asia, 73% in Latin America, 39% in the Middle East, and 20% in Africa. Barring a catastrophe, there will never be more than a billion people in poverty in the future history of the world.

This has been known to biologists for ages. In The Red Queen, I challenged readers to explain why bodies should be designed that way: why set up an immune system in such a way that it gets hindered by normal hormonal action? I still find it baffling. Over the years readers took up my challenge and wrote to me. They still do. Their answers nearly always boil down to a version of this: to weed out weedy males. That is to say, if males cannot both keep their testosterone levels up and resist disease they don't deserve to contribute to posterity's genes.

Trouble is, like all group selectionist arguments, it's vulnerable to the evolutionary free rider. Along comes a mutant animal that breaks the link between testosterone and illness and hey presto it can breed away to its gonads' content, propagating its subprime genes as if they were triple A.

Then there's the old 'constraint' argument - that the system's built that way because it's the only way mother Nature knows how to build it. Not very satisfying. Mutation finds a way round most obstacles.

In the new study, Olivier Restiff says it's all about reinfection. If males, which are the 'live hard die young' sex, are only going to get reinfected quickly, then there's no point wasting energy clearing previous infections. Divert the energy into fighting instead.

"The finding suggests an undocumented human species lived alongside Neanderthals and early modern humans in parts of Asia as recently as 30,000 years ago."

Leave aside the fact that it's just a bone from a little finger, leave aside the fact that they have only sequenced some mitochondrial DNA, not nuclear DNA. Assume, for the sake of argument, that they have ruled out contamination. Applaud - as we should - the achievement of recovering DNA from the fossil and sequencing it.

But don't call it a new species yet. It's far more likely that it just shows genetic diversity within the Neanderthals, of roughly the same depth as is found within existing chimpanzees. We modern humans, descended from a tiny tribe of east Africans who lived 200,000 years ago, are the odd ones out in being so genetically monotonous. Most species are like chimps: lots of ancient genetic diversity within a broad geographical range but still connected by interbreeding. Until somebody produces better evidence, it's a race of Neanderthal. Nature should be more cautious.

Yet here is whatThe Telegraph says:

The best evidence for climate change, however, is from phenology, the study of natural phenomena (seewww.naturescalendar.org.uk): "Spring is coming about two weeks earlier than it would have been 30 to 50 years ago, and autumn about a week later," says Jill Attenborough of the Woodland Trust.

Somebody forgot to tell the chiffchaffs.

Frankly, where I live there's been no consistent, discernible change one way or the other in my lifetime. Some years like this one the daffodils and snowdrops are weeks late. Some years like last year, the hawthorn buds are weeks early. Depends on the weather. I suspect what the phenology folk are measuring is the same oldurban heat island effect: spring flowers bloom and birds nest earlier in towns than the countryside, because it is warmer.

Speaking of chiffchaffs, here's a prediction: that this is going to be a great year for them and for other warblers. Why do I say that? Because it's been a harsh winter that has killed a lot of robins, wrens, goldcrests, tree creepers, tits and the like. So there's less competition from the over-wintering birds for the ones that have spent the winter in Africa. Bird bores rarely think about competition, but it's key. Why have resident birds done so much better than migrants over the past few decades: because of bird tables. Redstarts, ring ouzels, whinchats, tree pipits and willow warblers arrive back from Africa to find their wintering cousins fat and healthy: robins, blackbirds, stone chats, meadow pipits and blue tits. Why risk a five thousand mile trip across the Sahara if there are bird tables just down the road?

"The result has been an ever-escalating set of demands on climate science, with greens and their allies often attempting to represent climate science as apocalyptic, imminent, and certain, in no small part so that they could characterize all resistance as corrupt, anti-scientific, short-sighted, or ignorant. Greens pushed climate scientists to become outspoken advocates of action to address global warming. Captivated by the notion that their voices and expertise were singularly necessary to save the world, some climate scientists attempted to oblige. The result is that the use, and misuse, of climate science by advocates began to wash back into the science itself.''

Those of us who love science - the habit of licensed curiosity, not the bureaucratic machine - have been increasingly dismayed by the way that its high priests have been behaving over the climate issue: trying to politicize, propagandise  and polarize where they should be questioning, debating and being awkward. The most shocking thing to me about 'Climategate' was not the emails, but the any-excuse-will-do reaction to them from the scientific establishment.

I have frequently been surprised by how authoritarian many scientists are when you scratch the surface of their politics. James Lovelock (the idolization of whom baffles me, though I am sure he is a perfectly nice bloke) exemplified this yesterday in the Guardian.

'One of the main obstructions to meaningful action is "modern democracy", he added. "Even the best democracies agree that when a major war approaches, democracy must be put on hold for the time being. I have a feeling that climate change may be an issue as severe as a war. It may be necessary to put democracy on hold for a while." '

Cripes.

It's higher than it was before:

"The changes on the Greenland ice sheet are happening fast, and we are definitely losing more ice mass than we had anticipated," says study co-author Isabella Velicogna of the University of California-Irvine.

Could be scary? USA Today has its cake and eats it:

``If the entire Greenland ice sheet melted, which is not predicted, scientists estimate that global sea levels would rise about 20 feet, according to the National Snow and Ice Data Center.''

Is there a single journalist out there who bothered to ask the obvious question: what percentage of its ice mass is Greenland losing each year, so how long have we got before the 20 feet engulf us all?

Not that I could see. So I looked it up.

The new study says Greenland lost 385 cubic miles between 2002 and 2009. Sounds a lot.

Greenland has 700,000 cubic miles of ice. (http://en.wikipedia.org/wiki/Greenland_ice_sheet)

So it's losing 1% per century, 0.01% per year. Funny that number never appeared in the news reports.

For Pete's sake, journalists, do your job.

Centralized electricity changed energy production from a difficult, in-home process that kept the messy by-products of progress literally in your face, into something magical that happened when you threw a switch. The choking smoke was still there, but not at your house. There was still heavy labor involved, but it wasn't done by you or your children. For the first time, people were able to pretend that their standard of living was provided, free of downsides, by little elves that lived in the wall. All benefit, no detriment. Action without consequences. In other words, this is the point where everybody went a little bit bonkers.

The beauty is that this is still happening in parts of Africa and Asia. A report on the Philippines estimated that each family derives $108 a month in benefits from connecting to the electricity grid - cheaper lighting ($37), cheaper radio and television ($19), more years in education ($20), time saving ($24) and business productivity ($8).  As the miracle of electricity reaches a village, people inhale less smoke, read more school books, cut down fewer trees and find time to do other things that earn them more money.

The people who run the power stations aint elves but have comparatively well paid jobs that enable them to be customers to their customers.

The Telegraph: Missing link between man and apes found.

The Sunday Times: Fossil from cave is a 'missing link'

The cliche is misleading. The new fossil is a very complete and therefore very interesting specimen from a poorly understood period. If it proves to have features of both Australopithecus and Homo habilis, that's intriguing and surprising.

But it is absoluitely nothing to do with the common ancestor of man and apes, which lived 6 million years ago, not 2 million. That's the long accepted meaning of the phrase `missing link'.

At least the Times uses the phrase `a missing link'. But it's only true in the most trivial sense. Every link in a chain of fossils is missing till it's found.

This PR hype is becoming a habit in paeoanthropology. A year ago, ridiculous secrecy and jamboree surrounded the announcement of a 47 million year old fossil primate from the Messel pit in Germany. Called Ida, or Darwinius, it too was described as the missing link and given ludicrous star treatment. in an attempt to recoup the huge sum spent by a museum buying it off a collector.

It was just a very well preserved fossil of a very early primate, probably on the lemur lineage. Or as one paleoanthropolgist put it to me: `It's a f***ing lemur'.

This is not the 17th century, when "beliefs" trumped science, forcing Galileo to recant his understanding of the solar system

and

Religions across the spectrum -- Catholics, Jews, Mainline Protestants, Eastern Orthodox, and Evangelicals -- are united in seeing climate change as a moral and ethical challenge.

In the rest of the article, Hansen makes the quite sensible point that if you want to reduce carbon emissions then the only way to do it is a revenue-neutral, loophole-free carbon tax whose revenues all go straight back to citizens as green dividends.

Update

More Galileo parallels in Daniel Henninger's perceptive piece in the Wall Street Journal (hat tip Bishop Hill):

The East Anglians' mistreatment of scientists who challenged global warming's claims-plotting to shut them up and shut down their ability to publish-evokes the attempt to silence Galileo. The exchanges between Penn State's Michael Mann and East Anglia CRU director Phil Jones sound like Father Firenzuola, the Commissary-General of the Inquisition.

For three centuries Galileo has symbolized dissent in science. In our time, most scientists outside this circle have kept silent as their climatologist fellows, helped by the cardinals of the press, mocked and ostracized scientists who questioned this grand theory of global doom. Even a doubter as eminent as Princeton's Freeman Dyson was dismissed as an aging crank.

Henninger's main argument is that scientists do not realise how muhc harm the politicisation of climate science has done to all science, not just climate science:

Science is on the credibility bubble. If it pops, centuries of what we understand to be the role of science go with it.

In sum, the U.S. is on the verge of a demographic, economic and social revival, built on its historic strengths. The U.S. has always been good at disruptive change. It's always excelled at decentralized community-building. It's always had that moral materialism that creates meaning-rich products. Surely a country with this much going for it is not going to wait around passively and let a rotten political culture drag it down.

Moral materialism is not a bad phrase for what Joe Henrich and his colleagues are discovering, namely that the more people depend on others for goods and services through markets, the nicer they are.

As Jennifer Doudna at U C Berkeley puts it in Erika Check Hayden's Nature article about the tenth anniversary of the first draft of the human genome sequence:

"The more we know, the more we realize there is to know."

In particular, the way that genes get regulated used to be a simple nugget of knowledge:

`a regulator gene codes for a regulator protein that controls transcription by binding to particular site(s) on DNA'

Now it's a gorgeous mess of ignorance involving small RNAs with poorly understood regulatory roles.

That's thrilling, because ignorance is the fun part of science. Before we knew there were ice ages we did not ahve the fun of trying to understand them; before we knew there were subatomic particles, we did not enjoy the thrill of trying to get our minds around them.

Will somebody please tell young people this? the way science gets taught -- as a catalogue of facts -- puts them off becoming explorers of ignorance.

Here's what the researchers, led by Dr Dora Biro of Oxford, say:

The authors say that a hierarchical arrangement may foster more flexible and efficient decision-making compared with that of singly led or egalitarian groups. In future studies, the scientists plan to investigate whether leaders are better navigators, and whether hierarchies persist in larger groups and in other types of social animal. "If it's true that there's an evolutionary advantage to making decisions in this way, then there's absolutely a reason to assume that it could have evolved in other species too," Biro says.

That matches neatly what people like Joe Henrich have begun to conclude about how human society works. Nobody's in charge. No single leader decides what's going to be invented or eaten or laughed at. But certain prestigious individuals have more say than others.

Right, so can we now get away from the absurd dichotomy between autocracy and anarchy? If you say you favour bottom-up, emergent solutions with nobody in charge, because that's how both evolution and economic progress (and the internet) generally work, then then most people react by saying: well, somebody's got to be in charge or you'll end up with anarchy. No.

It's an easy trap, to think that the past was better or more free than the present. It's not hard to show that the past was poorer for most people, but was it more free?

Conservatives and libertarians often like to imply that life was better in the old days, because the weight of bureaucratic government rested lighter on people's shoulders, but even socialists like Rousseau, Engels or William Morris used to hark back to noble savagery, egalitarian peasantry or Merrie medieval England before the Norman yoke for their golden age. Back in the golden age itself, Hesiod was complaining that things were worse than they used to be.

And as the bureaucratic monster invents ever more ingenious ways of telling me what I cannot do without asking it first, I too succumb to the temptation from time to time to wish I were back in a more free time.

But that's because I make the mistake of thinking I would be in the elite in the past. Just as people who think themselves to be reincarnations from the past usually claim to be Napoleon, or Jesus, never Bert Bloggs, peasant, so we tend to forget that statistically you had far more chance of being a bonded servant, an indentured apprentice, a chattel wife, or a slave at any time in the past.

If you think you were free in, say 1700, try defying the customs man, the press gang or the local priest or the debtor's jail.

David Boaz of Cato reminds the mostly libertarian readers of Reason magazine that 19% of Americans were slaves in the 1700s.

Has there ever been a golden age of liberty? No, and there never will be. There will always be people who want to live their lives in peace, and there will always be people who want to exploit them or impose their own ideas on others. If we look at the long term-from a past that includes despotism, feudalism, absolutism, fascism, and communism-we're clearly better off. When we look at our own country's history-contrasting 2010 with 1776 or 1910 or 1950 or whatever-the story is less clear. We suffer under a lot of regulations and restrictions that our ancestors didn't face.

But in 1776 black Americans were held in chattel slavery, and married women had no legal existence except as agents of their husbands. In 1910 and even 1950, blacks still suffered under the legal bonds of Jim Crow-and we all faced confiscatory tax rates throughout the postwar period.

When the pessimists tell you that things are getting worse, don't even concede that liberty's slipping away. Red tape may be tiresome, but slavery's worse.

Are they:

a) natural?

b) evidence of supernatural forces?

c) man-made?

As some of you know, crop circles -- those neat patterns that appear in British wheat fields in summer -- did more than any other phenomena to convince methat lots and lots of otherwise intelligent human beings can also be irredeemably credulous, gullible and plain irrational, not to mention prone to thinking what other people tell them to think.

It boggled my mind when I realised in the 1990s that there were people --including serious journalists -- who not only believed these things could not be man-made, but believed that `cereologists' -- self-appointed prophets and publishing profiteers of crop circles -- were `experts'.

So I went out and made some crop circles. It's not hard.

Well now, comes shocking news. News that brings together two of my favourite subjects: crop circles and DNA. Clearly I was wrong. It's time to admit defeat and to welcome a new and brilliant theory, an idea so extraordinary that all of science is a mere prelude to it. Crop circles were made by... well, I can't understand what follows but maybe you can:

The findings of the molecular biologists Dr Pjotr P. Garjajev and Dr. Vladimir Poponin of the Russian Academy of Science concerning the 'Phantom-DNA Effect' have a radical connection with the formation of crop circles in the United Kingdom and throughout the world in recent times. According to these scientists the DNA is emitting electromagnetic waves that continue to manifest even after the DNA sample has been removed from the experiment. Hence the name 'Phantom-DNA Effect'. The genetic procedures being adopted by these scientists have been commented on and explained by Grazyna Fosar and Franz Bludorf in their book Vernetzte Intelligenz (1), who have put forward the theory that self-radiating balls of light often seen in the sky and mistaken for extra-terrestrial visitors are in fact a group consciousness phenomenon brought about by hypercommunication within the DNA. This theory by Fosar and Bludorf can also explain the formation of crop circles which are also commonly attributed to extra-terrestrial visitors. In addition it will be shown that the precise technology being adopted by the aforesaid scientists in Moscow represents a new energy source, previously unknown to mankind, that is capable also of creating crop circles.

Hold the front page, reserve the Nobel prizes, set up a new United Nations agency! A new age is dawning.

While they were developing this energy, the divine intelligence in the DNA was creating these crop circles using exactly the same source of energy, as a means of demonstrating to us how the Universe was created in the first place, and how it may now be modified and colonized.

Crop circles taught me never to underestimate human credulity. Ever.

He pores over thousands of records from birdwatchers in the Arctic and concludes that weather-related events kill a lot of them. Fulmars run into cliffs in fog, Murres get buried in landslides when cliffs collapse. Birds get swept away in storms. And so on.

Now the scientist has two options. He can say in a paper that a lot of Arctic birds die due to `factors related to weather' and bask in perpetual obscurity. Or he can slip in, just before the word `weather', the phrase `climate and'.

Kazam!

He could even add a little speculation that

`If temperatures warm and intense storms in the Arctic increase, along with otherclimate factors, "we might see mortality in these birds from these things increase from what they are now."

Note:if, and, might. Note too:

Mallory adds that he and his team are not sounding an alarm bell that climate change is going to kill off all of the seabirds.

Yet suddenly he's on the front page of the Huffington Post! `Strange, Random, Arctic Bird Deaths Caused by Climate Change' shouts the headline. No ifs and mights there. No `not sounding an alarm bell'.

It's not his fault, of course. None the less, now do you understand why scientists are tempted to link their work to climate change whenever possible? Why the incentives -- financial and reputational -- to sound alarm bells are so massive?

Here's a list of just some of the things that have been `linked to climate change'.

The lengths that acid rain alarmists in the EPA went to to prevent the result of the NAPAP study reaching Congress before crucial votes in the early 1990s is well documented, and this was when this phenomenon first dawned on me. But now I see it everywhere.

Journalists rarely challenge pressure groups' claims of urgency and deterioration, because those are the two things that get editors' attention, too.

This week saw a pleasing exception: a newspaper that was prepared to lift the lid on the pessimist cabal.The New York Times ran a front page piece about the worldwide decline in maternal deaths reported in the Lancet. The piece revealed that the Lancet's editor, Richard Horton, had come under pressure to delay the paper lest it reduce funding opportunities for pressure groups.

But some advocates for women's health tried to pressure The Lancet into delaying publication of the new findings, fearing that good news would detract from the urgency of their cause, Dr. Horton said in a telephone interview.

Maternal deaths had been declining steeply till the early 1990s when the improvement stalled -- chiefly because of the African HIV epidemic. It has recently resumed in earnest and is now dropping steeply:

Yet some people did not want you to know this:

Dr. Horton said the advocates, whom he declined to name, wanted the new information held and released only after certain meetings about maternal and child health had already taken place.

He said the meetings included one at the United Nations this week, and another to be held in Washington in June, where advocates hope to win support for more foreign aid for maternal health from Secretary of State Hillary Rodham Clinton. Other meetings of concern to the advocates are the Pacific Health Summit in June, and the United Nations General Assembly meeting in December.

This is wrong on all sorts of levels. First, because it shows a staggering arrogance among pressure groups about who should be allowed to know the facts -- almost amounting to attempted fraud. Second, because the way to encourage people to fund projects is to show evidence that they work , not that they are futile and ineffective. One might almost suspect that these groups would prefer maternal mortality to remain high.

Or, as a prominent climate scientist said in another context,

If we want a good environmental policy in the future we'll have to have a disaster.

(As somebody quipped on the radio, `Dear Iceland, we said send CASH'.)

So there are no vapour condensation trails from jets, which prompts the thought: did anybody ever figure out what con trails do to the climate?

One study estimated that the 3-day shutdown in US aviation after 9/11 increased diurnal temperature range by 1C!

Another study in the Journal of Climate in 2004 concluded that:

It is concluded that the U.S. cirrus trends are most likely due to air traffic

and

the cirrus trends over the United States are estimated to cause a tropospheric warming of 0.2-0.3C [per] decade

That's huge. Anybody know if these studies still hold up?

The unthoroughness, biased membership and gullibility of the Oxburgh and Russell inquiries has the effect on a lukewarmer like me of driving me further into the sceptical camp. If the case for man made global warming needs this much flagrant whitewashing, then maybe, I begin to think, the exaggerations and mistakes are not just the result of sloppiness, but are part of a deliberate attempt to camouflage the truth to keep the gravy train on the track. If the science was any good then it could stand proper scrutiny.

As Christpher Booker writes:

Nothing will do more to reinforce suspicion of the CRU's conduct than the failure, first by those MPs, and now by the team led by Lord Oxburgh, to address properly the way in which it appears to have abused the principles of true science - a scandal which should be of concern not just to us here in Britain, who paid for it, but across the world.

The incomparable Clive Crook made a similar point when the emails first surfaced back in Novermber:

I'm also surprised by the IPCC's response. Amid the self-justification, I had hoped for a word of apology, or even of censure. (George Monbiot called for Phil Jones to resign, for crying out loud.) At any rate I had expected no more than ordinary evasion. The declaration from Rajendra Pachauri that the emails confirm all is as it should be is stunning. Science at its best. Science as it should be. Good lord. This is pure George Orwell. And these guys call the other side "deniers".

...Remember that this is not an academic exercise. We contemplate outlays of trillions of dollars to fix this supposed problem. Can I read these emails and feel that the scientists involved deserve to be trusted? No, I cannot. These people are willing to subvert the very methods-notably, peer review-that underwrite the integrity of their discipline. Is this really business as usual in science these days? If it is, we should demand higher standards-at least whenever "the science" calls for a wholesale transformation of the world economy. And maybe some independent oversight to go along with the higher standards.

The scientist Terence Kealey said to me recently that:

Science was never a public good, nor was it ever anything but a club

I have a horrid suspicion that defending the club is taking precedence over seeking the truth. It takes a lot for a science groupie like me to lose this much faith in the science establishment. Think how much more damage is being done among those who are not science groupies.

It now turns out Europe's reaction was more extreme than America's would have been. And airlines are increasingly calling the bluff of the aviation authorities by doing test flights. Politicians have been characteristically slow and useless. See here:

The International Air Transport Association...expressed its "dissatisfaction with how governments have managed it, with no risk assessment, no consultation, no coordination, and no leadership"

Like all civil servants the aviation authorities are tasked with looking at only one risk in isolation. Yet as always there is a balance of risk. The risk of aeroplanes failing is balanced every normal day against the risk of not having imported food, imported medical supplies, a job, a chance to visit friends abroad or whatever. That flying a plane carries risks does not mean that you do not fly planes. How big a risk?

As Richard North diagnoses, there's a computer model fetish at work here, too:

Once again, therefore, it looks as if ministers have been asleep on the job, letting the techies play with their computer models, without adequate supervision. But the real fault goes back to 2009 when the disastrously inadequate IACO contingency plan was agreed, lacking precisely the "risk assessment" that Bisignani is now calling for. The reliance on this and the Met Office with its computer models has produced a mix far more toxic and damaging than any volcanic cloud, seemingly beyond the reach of ministers. As with global warming, and Foot & Mouth in 2001, they appear to be besotted with computer models, rejecting real-world experience for the allure of glitzy graphics and animations.

And this is now a systematic problem. Every scare is magnified, every inconvenience and hardship from the over-reaction is ignored. Not a single bureaucrat has been taken to task for the grotesque over-reaction to swine flu last year. There's an attempt to blame it on the pharmaceutical industry. But where Big Pharma could not believe its luck, it was the WHO bureaucrats and their national poodles who ordered the vaccines and the one-sided press briefings.

For an aviation bureaucrat there is simply no down side to closing down a country's air space. That's the trouble with command and control systems. Let the airlines decide whether it is safe to fly.

David Brooks in the New York Times has news of a contrarian finding about the internet:

Gentzkow and Shapiro found that the Internet is actually more ideologically integrated than old-fashioned forms of face-to-face association - like meeting people at work, at church or through community groups. You're more likely to overlap with political opponents online than in your own neighborhood.

This study suggests that Internet users are a bunch of ideological Jack Kerouacs. They're not burrowing down into comforting nests. They're cruising far and wide looking for adventure, information, combat and arousal. This does not mean they are not polarized. Looking at a site says nothing about how you process it or the character of attention you bring to it. It could be people spend a lot of time at their home sites and then go off on forays looking for things to hate. But it probably does mean they are not insecure and they are not sheltered.

Till now, most people had assumed that the internet was helping people reinforce their prejudices so we would all sink into mutually hating tribes. Maybe that's wrong, in which case, yet another attempt to find a the cloud behind the silver lining of instant access to almost all ideas bites the dust.

Yesterday I met the remarkable social entrepreneur Noam Kostiucki, founder of Seeducation, and we had a good moan about how everybody seems to think wikipedia's destroying students' capacity to learn and how in the internet age university education is still conducted as if it was the fifteenth century. Here'sNoam's take:

Maybe some things have changed. This whole internet thing is AMAZING: where was I when it all happened?! It is completely UNBELIEVABLE what is happening to our world! It is all so... different from what I was used to, and yet, so exciting!

I am so amazed that we can communicate for so cheap, and that we have access to so much information. This whole Facebook, Twitter and YouTube thing: fantastic! Keeping track of friends even after 20 years of not seeing each other, or getting instantenous news everywhere, or even sharing so many fun, interesting, inspiring and ridiculous videos. I can only say: WOW!

So I have to admit that maybe the world IS a bit different than when I grew up... and god knows what it will look like in 5 years, let alone 10 or 20! Now I find it funny that we really think that we can prepare our youth the way we were taught. I laugh so much just thinking about it! Now, seriously, we NEED to teach them SUCH different stuff. They have no chance in the future if we don't prepare them...

People were just as suspicious of the first railways, as Christian Wolmar reminds us today:

Many believed a clanking smoke-belching train would frighten the cattle, stop their hens laying and ruin their fox hunting, as well as spoiling the view from their front windows.

The clues come in the form of widely differing DNA sequences that seem to converge on common ancestors that lived long before modern human beings came out of Africa 80,000 years ago or so.

There is good reason to be cautious -- it is possible that it just means lots of very distantly Africans joined the migration -- but now it seems a tipping point is being reached in the debate. The latest study of 600 microsatellite (fingerprint) sequences from 2,000 people is being interpreted as evidence of two separate episodes of genetic mixing between Neanderthals (or heidelbergensis) and ex-African `moderns'. SeeNeanderthals may have interbred with humans.

John Hawks, who has good instincts in these matters, reckons the conclusion is probably right:

I take it as very likely that the strict out-of-Africa replacement without interbreeding is no longer credible. We've moved beyond it, and all these papers are testaments to that.

We will soon know much better when Svante Paabo publishes the Neanderthal genome, having extracted fragmented DNA from bones found in a Croatia and Spain.

The Implications of this are big, but it's important not to mislead. It means there were a few mixed-race people in Eurasia by 40,000 years ago and some of them had babies. But they were probably few. Few or none of those babies' descendants  ended up back in Africa. It means that some of the confusing skulls and bones from the `frontier' of African advance into Eurasia might be mixed-race. It means that there's a tiny bit of Neanderthal in some of us, but not all.

By the way, it's never been clear that Neanderthals were stupid. Their brains were often bigger than ours. But they did lack a fast-changing  tool kit, and they also lacked trade -- their artefacts never travelled far. Those two things go together. Trade creates a collective intelligence that far surpasses what individual brains can muster.

Environmentalists explain away this inconvenient truth as merely implying that we have managed to postpone disaster and it will be all the worse when it comes. But it's far more plausible that what's going on is that much new technology actually reduces impact.

The acres needed to support a single person's lifestyle keep going down and down. Today the same 700m hectares of land devoted to growing cereals produce three times more food than they did in 1961. Today burning coal to make electricity is 40% efficient, whereas a Newcomen engine was 1% efficient.

Those are food and fuel example, but there are others relating to shelter, clothing and even light. An electric light bulb requires far, far less land than a tallow candle made from the fat of a sheep did -- for an equivalent amount of light. (Does anybody have the exact numbers here: I have been trying to find out how many candles could be made from a single sheep or a single sperm whale spermaceti organ?)

Land isn't everything, of course. But the same is true of other resources. Whales, for example. If petroleum had not been discovered, most whales would be extinct.

No coincidence that the models were built for radioactivity. Ash, chemicals, fallout and heat are things which are not linear in their risk. That is to say, a very low dose is not slightly more dangerous than no dose. It's no more dangerous. This is not true of burglars and smallpox viruses.

Here's my contribution to the Edge collection:

The ash cloud reminds us of the risks of risk aversion. Shutting down Europe's airspace removed the risk of an ash-caused crash, but it also increased all sorts of other risks: the risk of death to a patient because an urgent medical operation might have to be postponed for lack of supplies, the risk of poverty to a Kenyan farm worker because roses could not be flown to European markets, the risk of a collision between ferries on extra night-time sailings in the English Channel. And so on. Risk decisions cannot be taken in isolation. The precautionary principle makes too little allowance for the risks that are run by avoiding risks - the innovations not made, the existing suffering not alleviated. The ash cloud, by reminding us of the risks of not being able to fly planes, is a timely reminder that the risks of global warming must be weighed against the risks of high energy costs - the risks of poverty (cheap energy creates jobs), of hunger (fertiliser costs depend on energy costs), of rainforest destruction and indoor air pollution (expensive electricity makes firewood seem cheaper), of orangutan extinction in subsidised biofuel palm oil plantations.

Oh, and remember the lessons of public choice theory: if you set up a body called the Volcanic Ash Advisory Centre, don't be surprised if it over-reacts the first time it gets a chance the demonstrate that it considers itself - as all public bodies always do - underfunded.

Update: See Brendan O'Neill's hilarious skewering ot the intelligentsia's moralistic reaction to the ash cloud:

...the excitable idea that one volcanic belch has reminded us how small we are reveals what lies behind the contemporary green outlook: a misanthropic view of mankind as a cocky and destructive species which needs to be firmly put back in its place. It is striking that even a natural event which cannot in anyway be described as 'manmade' has unleashed so much nature-dominates-man commentary. This shows that, for all contemporary commentators' claims that they are only interested in communicating the 'scientific facts' about what will happen if we continue distorting and warping the natural world with CO2, in fact they are instinctively drawn to any natural occurrence that can be held up as evidence of Mother Nature's power over deluded mankind.

Everyone employed chained labour -- captured slaves, convicts, and, in the Christian ships, paupers so destitute they sold themselves to the galley captains. It was these wretches, chained three or four to a foot-wide bench, who made sea wars possible. Their sole function was to work themselves to death. Shackled hand and foot, excreting where they sat, fed on meagre quantities of black biscuits, and so thirsty they were sometimes driven to drink seawater, galley slaves led lives bitter and short.

And this:

Bragadin's end was lingering and dreadful. He was kept alive until August 17, a Friday. The wounds on his head were festering; he was crazed with pain. After prayers, he was processed through the city to the sound of drums and trumpets...More dead than alive, he was tied in a chair and hoisted to the top of a galley's mast, ducked in the sea, and shown to the fleet with jeers and taunts...Then he was hustled into the square beside the church of Saint Nicholas, now converted into a mosque, and stripped naked. The butcher ordered to commit the final act -- and this would not be forgiven in Venice-- was a Jew. Tied to an ancient column from Salamis still standing to this day, Bragadin was skinned alive. He was dead before the butcher reached the waist.

Until I read Crowley's book I knew little about the struggle between the Ottoman and Spanish empires to dominate the Mediterranean in the sixteenth century, with the Pope, Venice, the Knights of St John and the Barbary corsairs as their allies and proxies. It was a time of such horror that much of southern Italy, Greece and north Africa ended the century severely depopulated by the slave raiders in search of galley fuel. The cruelty of both sides defies belief, as does both sides' complete conviction that they were acting in the name of a virtuous God.

Now I understand better how Spain squandered the riches of south America. (Charles V built a fleet with a Peruvian windfall and lost that fleet and most of his men in a single abortive attack on Algiers.) Now I understand how the Ottoman empire destroyed its own prosperity. (The sultan requisitioned vast quantities of men, food, weapons and supplies then destroyed them all in long sieges of Rhodes, Malta and Cyprus.) Now I understand how the trading city states of Italy got sucked into the pursuit of war rather than business.

It is clear that, as always, ordinary people wanted to carry on with commerce, but chiefs, priests and thieves -- sultans, emperors, popes, pashas, holy knights and corsairs -- just kept plundering the fruits of that commerce for their own enrichment and their own glory. Little wonder that, as the historian Meir Kohn concludes, preindustrial government was predominantly predatory in nature.Not that it is entirely free of that suspicion today.

So next time you hear somebody tell you any of the following things, urge them to read Empires of the Sea:

1. Life was better in the past

2. Faith and glory are virtues

3. Commerce is evil

I call these books The Emperor's New Clothes Trilogy. Their broad lesson:Sometimes the "best people" aren't right. Sometimes there's a point of view from which they're glaringly wrong. The Hockey Stick Illusion is about how Stephen McIntyre found this point of view. In No One Would Listen Markopolos found this point of view. In The Big Short several people found this point of view.

In Monty Python's immortal words:

Brian: ``you've all got to work it out for yourselves''

Crowd: ``yes, we've all got to work it out for ourselves.''

Now he has a new book, which I have just kindled, on the myths of green energy, called Power Hungry.

He summarises his argument in the Washington Post. One fact that jumps out is how much worse the dependence on foregin powers green energy would be than even oil is:

In the new green economy, batteries are not included. Neither are many of the "rare earth" elements that are essential ingredients in most alternative energy technologies. Instead of relying on the diversity of the global oil market -- about 20 countries each produce at least 1 million barrels of crude per day -- the United States will be increasingly reliant on just one supplier, China, for elements known as lanthanides. Lanthanum, neodymium, dysprosium and other rare earth elements are used in products from high-capacity batteries and hybrid-electric vehicles to wind turbines and oil refinery catalysts.

China controls between 95 and 100 percent of the global market in these elements. And the Chinese government is reducing its exports of lanthanides to ensure an adequate supply for its domestic manufacturers. Politicians love to demonize oil-exporting countries such as Saudi Arabia and Iran, but adopting the technologies needed to drastically cut U.S. oil consumption will dramatically increase America's dependence on China.

So, explain to me again what's so wonderful about wind power? It requires a vast acreage, a huge regressive subsidy and rare materials from China; it kills eagles and other raptors by the hundreds (please watch this video), it produces a trickle of power and its intermittent nature means it displaces zero fossil fuel use. And it enriches plutocrats and corrupts environmental groups.

If Edward Abbey were alive, his Monkey Wrenchers would be destroying wind turbines today.

But it is worth pausing to reflect how rare such terrible oil spills have now become. Here is the data on world tanker spills over the past 40 years:

This despite a steady increase in the amount of oil transported by sea.

It is notable that 1979 saw not only the worst ever tanker spill -- the collision oif the Atlantic Empress with the Aegean Captain off Trinidad -- but also the worst ever rig spill: the IXTOC1 platform off Mexico, which spilled 138 million gallons into the Gulf of Mexico before it was capped. The current spill is thought to be leaking 200,000 gallons a day. The environmental effects of the IXTOC disaster were severe, but have not proved permanent. Not that this will be of great comfort to the people of Louisiana and neighbouring states.

Our studies are revealing high levels of capability and good quality life among people who are well into their 80s. They are not all in poor health needing high levels of care. Indeed, many view their health as 'excellent' and still live highly independent lives.

I point out in The Rational Optimist that the average lifespan has increased by a third during my lifetime; life expectancy is increasing globally by 5 hours a day. Kirkwood's Changing Age Charter, like my book, says:

Increased life spans represent one of humanity's greatest achievements

Of course two real problems do still exist: people who need care in old age and cannot afford it, and increasingly unsustainable commitments from a relatively shrinking workforce to pay pensions for longer. Such unfunded commitments could still bust many western economies if unreformed.

Neither problem is insoluble. Part of the solution is progressively later retirement, especially if people are in `excellent' health.

(graph from my book)

That remarkable achievement is mostly down to the fact that most farmers now get extra nitrogen straight from the air, via ammonium factories, rather than from plants, dung and dead fish -- the `organic' way.

If the world was fed with organic food, it follows, we would need to cultivate or otherwise exploit far, far more land to get the plants, dung and dead fish to produce the same amount of food. As I submit to being preached at by organic farmers about their virtue, this fact keeps creeping into my head. Wholly organic farming means no rainforests or it means hunger and high food prices.

The organic folk usually reply by saying that their farms are better for wildlife on a local level. Well, now comes a comprehensive study of British farmland that says they are not even achieving that:

While there were more plants and butterflies on organic farms, there was no difference in the number of bees and there were 30 per cent more hoverflies on conventional farms. Organic fields contained more magpies and jays but 10 per cent fewer small birds such as yellowhammers, corn buntings, linnets, skylarks and lapwings.

(More magpies, fewer songbirds: Duh! Magpies predate songbird nests.)

The study (original paper behind a paywall, but abstract here) also confirms that organic farming uses up more land to produce the same amount of food:

It concludes that organic farms produce less than half as much food per hectare as ordinary farms and that the small benefits for certain species from avoiding pesticides and artificial fertilisers are far outweighed by the need to make land more productive to feed a growing population.

Last year saw another organic myth laid firmly to rest, when Alan Dangour did a huge survey of all studies purporting to test the health benefits of organic food and found:

Our systematic reviews found that there was no evidence of any important differences in the nutritional composition of foodstuffs grown using conventional and organic farming methods. There was also no evidence of nutrition-related health benefits from consuming organically produced foods.

Bruce Ames long ago (here and here) laid to rest the myth that pesticide residues in conventional food pose a risk to human health:

The pesticides in our diet are 99.99% natural, since plants make an enormous variety of toxins against fungi, insects, and animal predators. Although only 50 of these natural pesticides have been tested in animal cancer tests, about half of them are carcinogens. About half of all chemicals tested in animal cancer tests are positive. The proportion of natural pesticides positive in animal tests of clastogenicity is also the same as for synthetic chemicals.

Given that organic farms use crushed fish, flame-throwing weed control, copper sulphate pesticides, poorly paid labour, and given that it still it takes just about the same calories of fossil fuels to get an organic lettuce from a Californian farm to a plate in New York -- 4,600 versus 4,800 (numbers from Michael Pollan's Omnivore's Dilemma) -- can we please have a little less preaching of organic's holiness?

By all means eat organic food if you want to. But be honest and admit that, as far as the health of the planet is concerned, you are being selfish, rather than virtuous.

Science magazine published a letter from 255 scientists (few of them climatologists) complaining in remarkably strong tones about

the recent escalation of political assaults on scientists in general and on climate scientists in particular.

asserting, amazingly, that there is

nothing remotely identified [sic] in the recent events that changes the fundamental conclusions about climate change

and lecturing us ex cathedra that

Many recent assaults on climate science and, more disturbingly, on climate scientists by climate change deniers are typically driven by special interests or dogma, not by an honest effort to provide an alternative theory that credibly satisfies the evidence

before calling for

an end to McCarthy-like threats of criminal prosecution against our colleagues based on innuendo and guilt by association

(Would that include this?

James Hansen, one of the world's leading climate scientists, will today call for the chief executives of large fossil fuel companies to be put on trial for high crimes against humanity and nature)

Science chose to illustrate this letter with a cover photo of a polar bear that was a photoshopped fake. They have now printed a correction.

Due to an editorial error, the original image associated with this Letter was not a photograph but a collage. The image was selected by the editors, and it was a mistake to have used it.

Steve McIntyre acutely observes the irony:

One of the apt ironies of this incident is that the notorious "trick" email describes a procedure that is essentially a "photoshopping" of the data - deleting adverse proxy data and merging with instrumental data - to give a false rhetorical impression in the diagram.

Yet, undeterred by the embarassment, the senior author of the letter now attacks climate moderates over the issue:

Of course scientist must try to get the facts as right as possible, and be willing to acknowledge and admit mistakes. And of course the photoshopped photo is a metaphor for the problem. But you (and many in the denial community -- a perfectly proper term, despite their complaining about it) are conflating my dismissal of the selection of bad ART, with my dismissal of those who would rather talk about ART as metaphor than science as fact.

and the editor of Scientific American somehow managed to argue that the episode reflects badly on sceptics.

The incident has become a perfect cameo of the larger climate-change issue: scientists speak out on the state of the research with facts and substantive arguments, and opponents jump on any small defects in what's said to argue, honestly or otherwise, that the climate science is wrong, corrupt or both.

Tip: this is not a good way to win over lukewarming moderates.

I was at a brilliant lecture by Bjorn Lomborg at the Royal Society of Arts last week and was amazed at the incoherent rage his mild and sensible lecture evoked in certain members of the audience.

I have seen science this polarised and politicised before, over the issue of nature and nurture, especially during the IQ, sociobiology and twin studies debates of 1970-1990.  What struck me when I went back and studied those debates for my book Nature via Nurture was the following simple observation:

Everybody reads the people they agree with; nobody reads their opponents' papers or books.

So the only thing they know about their enemies'  views is what their friends say about them.

Admit it: you do this. I know I do, though I nowadays try hard not to.

This is how scientific arguments get polarised.

Ludicrous things continue to be said about twin studies to this day, for example, by people who are astonishingly unaware of the facts because they have never read the original studies, only critiques of them.

Hence the extraordinary spectacle of John Rennie saying with a straight pen that the hockey stick graph has been vindicated. He's presumably not read Montford.

Please will both sides of the climate debate read each other's best work?

The Economist

Over the past decade, a wave of drilling around the world has uncovered giant supplies of natural gas in shale rock. By some estimates, there's 1,000 trillion cubic feet recoverable in North America alone-enough to supply the nation's natural-gas needs for the next 45 years. Europe may have nearly 200 trillion cubic feet of its own.

Imagine a source of energy...

that does not require the felling of forests, like wood

that does not require the flooding of valleys or damming of streams, like hydro

that does not require sending men underground, quarrying or using heavy rail cars, like coal

that if it leaks does not `spill' and kill wildlife, like oil

that does not need rare earths, huge landscapes and back-up power, like wind

that does not require insurance subsidy, like nuclear

that does not cost a fortune for every joule, like solar

that does not mean the loss of tidal habitats, like tidal

that works, unlike wave power

that does not mean taking food from the mouths of the poor, like biofuels

that produces half as much carbon dioxide as coal

that can be used for heat, cooking, electricity or fertiliser manufacture

that does not depend on weird regimes.

No wonder that Amy Myers Jaffe argues that

With natural gas cheap and abundant, the prospects for renewable energy will change just as drastically. I have been a big believer that renewable energy was about to see its time. Prior to the shale-gas revolution, I thought rising hydrocarbon prices would propel renewables and nuclear power into the marketplace easily-albeit with a little shove from a carbon tax or a cap-and-trade system.

But the shale discoveries complicate the issue, making it harder for wind, solar and biomass energy, as well as nuclear, to compete on economic grounds. Subsidies that made renewables competitive with shale gas would get more expensive, as would loan guarantees and incentives for new nuclear plants. Shale gas also hurts the energy-independence argument for renewables: Shale gas is domestic, just like wind and solar, so we won't be shipping those dollars to the Middle East.

The search is on for the bad news to hang round the neck of shale gas. Groundwater contamination is the chosen one. But the gas lies far beaneath most aquifers so it's not a persuasive worry yet. Truth is, shale gas looks like giving us the ideal cheap, safe, clean, easily transported, moderately-low-carbon bridge till new technology makes solar affordable in, say, the 2040s.

Every now and then, someone comes along to note that society has failed to collapse and might go on prospering, but the notion is promptly dismissed in academia as happy talk from a simpleton. Predicting that the world will not end is also pretty good insurance against a prolonged stay on the best-seller list.

Hope he's wrong about that, at least!

People speak about artificial life forms getting loose and running amok. But that's not how life works. It's a jungle out there.

Nature is continually trying new life forms on a truly gigantic scale and testing them against each other. Very few get to take over the world even briefly and even they soon succumb to evolving predators, parasites and competitors.

Anything a piddling little human mind -- or even one as big as Craig Venter's -- can design is going to be easy meat for the waiting hordes of predators, parasites and competitors. Don't forget that organisms are food.

(A funny version of Craig Venter's news at Discover's Blog)

I have a long article in the weekend edition of the Wall Street Journal.

It tries to explain how

the sophistication of the modern world lies not in individual intelligence or imagination. It is a collective enterprise. Nobody-literally nobody-knows how to make the pencil on my desk (as the economist Leonard Read once pointed out), let alone the computer on which I am writing. The knowledge of how to design, mine, fell, extract, synthesize, combine, manufacture and market these things is fragmented among thousands, sometimes millions of heads. Once human progress started, it was no longer limited by the size of human brains. Intelligence became collective and cumulative.

This explains why human beings suddenly experienced explosive progress after 45,000 years ago, following millions of years of culture that changes no faster than genes:

Dense populations don't produce innovation in other species. They only do so in human beings, because only human beings indulge in regular exchange of different items among unrelated, unmated individuals and even among strangers. So here is the answer to the puzzle of human takeoff. It was caused by the invention of a collective brain itself made possible by the invention of exchange.

This is an idea that has been slowly crystallising among anthropologists and archeologists for a while. I am trying to pull the threads together, as I do in my book.

Some nice lightbulb images:

"If people are all the same underneath, how has society changed so fast and so radically? Life now is completely different to how it was 32,000 years ago. It's changed like that of no other species has. What's made that difference? Clearly our genes haven't changed; this process has happened far too fast for genetic change. My answer, bringing together my evolutionary knowledge and a lot of economic reading, is this: sex is to biology as exchange is to culture."

Today, a car emits less pollution travelling at full speed than a parked car did in 1970 from leaks.

My source for this remarkable statistic was Johan Norberg's 2006 book När människan skapade världen. In a translation he sent me it reads:

the average car today gives off one-tenth as much pollution per kilometre as in 1970. The fact is that a car travelling full speed causes less pollution than a parked car did in 1970, because of leakages.

Recently Henry Payne gave some more details, quoting an article in Autoweek -- which is interesting, but a little confused in one place:

The 1970 Ford Mustang pollutes more parked in a driveway than a 2010 Mustang does traveling down the road...

The operating 2010 Mustang is 98.5 percent cleaner than the 1970 with its engine shut off, according to Ed Kulick, an emissions regulatory planner in Ford's vehicle Environmental Engineering Department.

The '10 Mustang has demand-based fuel injection with no return lines, hydrocarbon impermeable fluorocarbon gaskets and evaporative emissions canisters that eliminate gasoline vapor seepage, even during refueling.

The '70 Mustang emitted the equivalent of 3.7 grams of hydrocarbon (HC) per mile sitting still, according to Kulick. The '10 is certified at 0.055 gram of HC per mile when cruising the interstate at 70 mph.

The 1970 'Stang had Detroit's first rudimentary apparatus to control exhaust emissions It met federal standards of 4.3 grams of HC, 39.6 grams of carbon monoxide (CO) and 4.1 grams of oxides of nitrogen (NOx) per mile. The 2010 generates no more than 0.055 gram HC, 2.1 grams of CO and 0.070 gram of NOx, for reductions of 98.7 percent, 94.7 percent and 98.3 percent, respectively.

The confusion is this: a parked car cannot emit pollution `per mile', so `the equivalent of' needs explaining. The key measure would be `per minute'.  Can anybody shed light on this? I cannot track down the original Autoweek article.

In the last few years, Dr. Sands and other researchers have accumulated evidence that the well-known group of bacteria, long known to live on agricultural crops, are far more widespread and may be part of a little-studied weather ecosystem. The principle is well accepted, but how widespread the phenomenon is remains a matter of debate.

If true, this could have all sorts of implications.

The accepted precipitation model is that soot, dust and other inert things form the nuclei for raindrops and snowflakes. Scientists have found these bacteria in abundance on the leaves of a wide range of wild and domestic plants, including trees and grasses, everywhere they have looked, including Montana, Morocco, France, the Yukon and in the long buried ice of Antarctica. The bacteria have been found in clouds and in streams and irrigation ditches. In one study of several mountaintops here, 70 percent of the snow crystals examined had formed around a bacterial nucleus.

This ability to promote freezing of water at higher-than-normal freezing temperatures has led Dr. Sands and other scientists to believe the bacteria are part of an unstudied system. After the bacteria infect plants and multiply, he says, they may be swept as aerosols into the sky, where it seems they prompt the formation of ice crystals (which melt as they fall to earth, causing rain) at higher temperatures than do dust or mineral particles that also function as the nuclei of ice crystals.

Sands is telling us that the air is a habitat too.

By chance today my son and I were walking in the rain and we started imagining a future in whcih weather is controllable, but some countries decide when it should rain by political means -- referendums, committees, bureaucracies, protests -- while others leave it to the market.

We plan to write a Swiftian satire along these lines. One wet day.

and an MP3 of my interview on PM with Marc Colvin, in Australia

We have since discovered that the maximum density of ash (100 micrograms of ash per cubic metre) over the UK during the ban was one fortieth of that now deemed a safe threshold (4,000 micrograms of ash per cubic metre). In other words, the ban was nowhere near justified by what is now the official threshold.

He goes on to give some remarkable numbers from the similar over-reaction to avian flu:

Take the response to the avian flu outbreak in 2005. Dr David Nabarro, the UN systems coordinator for human and avian influenza, declared : 'I'm not, at the moment, at liberty to give you a prediction on [potential mortality] numbers.' He then gave a prediction on potential mortality numbers: 'Let's say, the range of deaths could be anything from five million to 150million.' Nabarro should have kept his estimating prowess enslaved: the number of cases of avian flu stands at a mere 498, of which just 294 have proved fatal.

And swine flu:

On 11 June 2009, just over a month after the initial outbreak in Mexico, the World Health Organisation finally announced that swine flu was now worthy of its highest alert status of level six, a global pandemic. Despite claims that there was no need to panic, that's exactly what national health authorities did. In the UK, while the Department of Health was closing schools, politicians were falling over themselves to imagine the worst possible outcomes: second more deadly waves of flu, virus mutation - nothing was too far-fetched for it not to become a public announcement. This was going to be like the great Spanish Flu pandemic of 1918-20. But worse.

However, just as day follows nightmares, the dawning reality proved to be rather more mundane. By March 2010, nearly a full year after the H1N1 virus first began frightening the British government, the death toll stood not in the hundreds of thousands, but at 457. To put that into perspective, the average mortality rate for your common-or-garden flu is 600 deaths per year in a non-epidemic year and between 12,000 and 13,800 deaths per year in an epidemic year. In other words, far from heralding the imagined super virus, swine flu was more mild than the strains of flu we've lived with, and survived, for centuries. Reflecting on the hysteria which characterised the WHO's response to Mexico, German politician Dr Wolfgang Wodarg told the WHO last week: 'What we experienced in Mexico City was very mild flu which did not kill more than usual - which killed even less than usual.'

In the same vein, I am wont to remind people of how `hundreds of thousands' of Britons were going to die of new variant CJD, the human form of mad cow disease. In fact the number of deaths never exceeeded 28 a year, has now fallen to 3 last year, one the year before, and the total is just 168. By all means let us be cautious, but can we not also treat extreme predictions about disease (or climate or pollution or anything else) with a little caution too?

Have a look at this image, which uses stalagmites in caves to estimate ancient temperatures (as graphed by Wilis Eschenbach)

Now have a look at this image, which uses oxygen istopes to measure temperature in ice cores:

Notice how very similar they are, and notice in particular how they both say that the last few centuries are by far the coldest period of the current interglacial. The Little Ice Age, they call it with good reason. Far from being unprecedentedly hot, the current world has only just recovered from being almost unprecedentedly cold - for the interglacial. (The sole exception, after the Younger Dyas ended, is the sudden and brief plunge in temperatures that happened 8,200 years ago.)

Again and again you read remarks like this, from a study of stalagmites in South Africa: `Maximum Holocene cooling occurred at AD 1700'.

By contrast the start of the interglacial was much warmer than today. How much warmer?

Between 8,000 years ago and 5,500 years ago the Greenland temperature apparently never got as low as today, and was sometimes -- 6,900 years ago and 7,700 years ago - even more than 3C warmer than today.

It follows that any suggestion that Greenland will melt at temperatures 3C warmer than today is unlikely to be true. The disappearance of Arctic Ocean sea ice during part of the summer would probably not be unprecedented either: the northern shore of Greenland shows evidence of driftwood and beach ridges raised by large waves during the Holocene Optimum on a coast that is nowadays ice-locked most of the year - implying that the Arctic Ocean was much freer of ice in summer than it is today

Polar bears would have taken refuge on land for a few weeks or months - as they do in Hudson's bay today.

But what about the rest of the planet? Throughout the northern hemisphere ice cores, lake sediments, marine sediments, pollen, tree lines and glacier histories all point to a culmination of the warmth around 7,000 years ago. By then, birch and larch trees grew much further north in all of Siberia than they do today, and one group of scientists reckons that Arctic Siberia experienced July temperatures a remarkable 2.5C-7C warmer than today.

A study of sea sediment cores in the Chukchi Sea shelf in the Arctic Ocean concluded that `during the middle Holocene the August sea surface temperature fluctuated by 5°C and was 3-7°C warmer than it is today'.

Yes, you read that right: up to SEVEN DEGREES CENTIGRADE.

China too abounds in evidence of warmth around 7,000 years ago

Ah, says the `climate consensus', but the Holocene Optimum was confined to the northern hemisphere during summer. Not so. Evidence from high latitudes in the southern hemisphere also shows warmth at the same time: Antarctic ice cores, Tasmanian and south African cave stalagmites . New Zealand glaciers, alkenones (algae derived fats) in seabed cores off Chile - they all point to a warm climate in the early Holocene before 7,000 years ago.

Well all right, said the IPCC, but the tropical oceans were cool, even though the high latitudes were warm.

Really? The only evidence comes from eight seabed cores taken from areas of ocean upwelling, which show slight warming rather than marked cooling since 7,000 years ago . But more cool upwelling generally indicates more warming elsewhere, so it is not clear what these eight cores are saying. The discovery of remains of alpaca moss (Distichia) from 5,000 years ago and 500 metres higher in the Peruvian Andes than it now grows, at a low latitude in the southern hemisphere (the plants had been covered by advancing glaciers some time after 5,000 years ago) seems at least to throw the burden of proof back on those who would argue for the Holocene Optimum being a solely non-tropical phenomenon .

And some of the speleothems in the first chart come from Costa Rica, southern China, Panama and Borneo. Tropical enough for you?

The Sahara, too, hints at a warm planet 7,000 years ago. The Sahara is always very arid during ice ages when the cool oceans starve it of seasonal rain. Its green and moist periods come during the warmest parts of interglacials. Its most recent really wet period lasted from 8,500 years ago to 5,300 years ago , coinciding with Greenland's least cold time. In this so called `African Humid Period', the Sahara was covered in forests, grasslands, and permanent hippo-filled lakes, and people drew rock art of crocodiles . The drying of the damp Sahara, after 5,300 years ago, coincides with a marked cooling in Greenland.

Remember 7,000 years ago is not the deep past. It is three millennia after the establishment of agriculture; settlements like Jericho were already 2,000 years old.

Ask yourself this: if the heat of 7,000 years ago, so widespread around the globe and so pronounced in the far north, did not cause planetary catastrophe, why should the lesser warmth of this century?

At first I had assumed that the quote, which I had found in another book, must be out of context. Surely nobody would say anything so foolish or so heartless. Surely he was caricaturing some blimpish view from a reactionary? So I looked up the original article, in The Ecologist in 2007, to be sure I was not being unfair to quote him thus. You can read the whole article here. Here's the longer context of the quote.

Yet the facts speak for themselves: the fewer there are of us, the greater our personal carbon budgets - and just remember we're starting from a baseline here in the UK of around 12½ tonnes of CO₂ per person! I can't tell you how politically incorrect it is to spell things out in those terms. Even those who are getting more and more enthusiastic about the idea of personal carbon budgets (including Environment Secretary David Miliband) wouldn't dream of giving voice to such a crass calculation. Leaders of our ever-so-right-on environment movement can barely bring themselves to utter the dreaded "p" word. The Millennium Development Goals don't mention population. Tony Blair's Commission for Africa ignored it entirely, even though it's blindingly obvious that completely unsustainable population growth in most of Africa will keep it permanently, hopelessly stuck in deepest, darkest poverty. Our very own Department for International Development grits its teeth and reluctantly doles out little bits of money for family planning projects, but the idea that it should be the Department's No 1 priority - if it was remotely realistic about its poverty alleviation aspirations - remains anathema to most officials and ministers.

This was the main thrust of the report on global population growth (albeit articulated somewhat less intemperately!) from the All-Party Parliamentary Group on Population at the beginning of February. On the basis of official hearings involving a vast range of national and international organizations, it comes to the simple but devastating conclusion that it will be "difficult or impossible" to deliver most of the Millennium Development Goals if population continues to grow at current rates, particularly in sub-Saharan Africa, the Middle East and parts of Asia.

Today another green English Jonathan, Dimbleby, has an article in the Telegraph about Africa that puts the continent in a rather different light. Dimblebdy's analysis is very much the same as my unfashionably optimistic one: Africa is beginning to prosper and has a bright future thanks to Chinese trade, retreating AIDS, improving demographics and returning entrepreneurial talent:

The Africans I met on my 7,000-mile journey through nine countries resent the pitying and patronising attitudes that are so often adopted towards them by a Western world which - from their perspective - doles out aid with one hand while nicking the oil and minerals (by which the continent is blessed in super-abundance) with the other. Again and again, at every level, people told me: "Don't give us aid - trade with us fairly. Stop ripping us off."...

Even accounting for the global financial crisis, many African countries have enjoyed growth rates of between 6 per cent and 10 per cent a year through much of the first decade of this millennium...

Imagine that in the decades ahead, Nigeria, Congo, Zimbabwe, Kenya and South Africa emerge from their various predicaments to unlock their huge potential as both producers and consumers. Africa is strategically located between East and West; it is rich in resources and talent. Given a fair breeze, it may well become the continent to reckon with in the 21st century. While never forgetting the other Africa with which we have long been painfully familiar, we should wake up to this Africa as well.

Now the Institute of Fiscal Studies has compiled data on average incomes in Britain since 1961, coming to the remarkable conclusion that

in real terms the bottom 25% are now considerable richer than were the top 25% in 1961.

Here's a graph, (hat tip Tim Worstall)

Of course this underestimates the increase in wealth because it does not measure the extent to which many goods and services have got cheaper during this time. Nor does it take any account of innovations: the products of Vodafone, Starbucks and Google were unobtainable at any price in 1961.

Unlike Monbiot's article, my book isn't about me. It's about the billions of other people in the world who, through ingenuity, exchange and specialisation, have generated remarkable prosperity.

Monbiot, remember is the man who once wrote: ``every time someone dies as a result of floods in Bangladesh, an airline executive should be dragged out of his office and drowned.'' (see, George, two can play at selective quotation).

Still, Monbiot goes on to make a number of specific charges against things in my book that he thinks are wrong. Here are my replies:

First Monbiot claims that the economic success of South Korea and Taiwan was down to protectionism and industrial strategy rather than free trade. Yet, as this article demonstrates, these two countries not only adopted more modest, more market-friendly and more progressively dismantled intervention than Latin American or East European countries, and found that many of their interventions failed to produce the desired results (ever heard of Taiwanese cars?), but in fact they probably thrived despite, rather than because of their industrial policies:

However, no matter how the relative weights are assigned, the experience of East Asia, supported by recent research on growth, has convinced many observers that an outward-looking development strategy, particularly a dynamic export sector, is conducive to growth.

It is clear from the East Asian experience that economies that have adopted sustained outward-oriented trade strategies have experienced economic performance superior to those that have not. This suggests that other emerging markets should pursue a development strategy that relies on integration with the world economy, rather than one that relies on insulation.

Next Monbiot claims that he cannot find evidence that Enron funded climate alarmism. Perhaps this email, cited in the source I quoted, helps. It is from an Enron official who attended the Kyoto climate treaty talks in 1997:

Through our involvement with the climate change initiatives, Enron now has excellent credentials with many "green" interests including Greenpeace, WWF, NRDC, GermanWatch, the US Climate Action Network, the European Climate Action Network, Ozone Action, WRI, and Worldwatch. This position should be increasingly cultivated and capitalized on (monetized).

Next, Monbiot claims that Howard Friel's book attacking Bjorn Lomborg proves that there are significant errors in Lomborg's work. Friel's book is itself packed with significant errors and is easily answered in Lomborg's rebuttal, available here. Lomborg's conclusion is as follows:

By his own account, Friel was aiming to write a book that would show that my work "is grounded in highly questionable data and analysis, and that there is little if any factual or analytic basis" for it.

In his longest chapter, Friel attempted to argue that my arguments were not supported by my source material. He claimed that endnotes were "missing" when they clearly exist, misread source figures and tables, relied on a misrepresentation of both my text and source material, and tried to shift the argument by claiming that I should have written about topics that he personally found more salient.

Next, Friel attempted to engage with my arguments on climate change. He did not participate in the relevant, constructive discussion about the economic arguments central to Cool It, but instead made a series of confused and confusing arguments. I was disturbed by his reliance on cut-and-pasted source material that often did not even match the topic that he was responding to. It was troubling to find that he was unable to differentiate between different sources of information. This was why he placed such great stock in news reports rather than peer-reviewed pieces, and is also why he placed credence in arguments such as the now debunked claim that the Himalayan glaciers would entirely disappear before 2035. I was alarmed to find that Friel was unfamiliar with economic basics such as the discount rate, but was more alarmed that his demonstration of this lack of knowledge could make it to print.

Monbiot should be embarrassed to be relying on a source of this quality.

Next Monbiot claims that recent temperature rises are the most rapid since instrumental record began. Notice the word `instrumental'. My point was partly that ice cores reveal much, much faster natural temperature rises in the past, during Dansgard Oeschger episodes in Greenland, for example. Yet even with this let-out Monbiot is wrong. Here is Dr Phil Jones of the University of East Anglia, answering a question from the BBC's Roger Harrabin:

A - Do you agree that according to the global temperature record used by the IPCC, the rates of global warming from 1860-1880, 1910-1940 and 1975-1998 were identical?

An initial point to make is that in the responses to these questions I've assumed that when you talk about the global temperature record, you mean the record that combines the estimates from land regions with those from the marine regions of the world. CRU produces the land component, with the Met Office Hadley Centre producing the marine component.

Temperature data for the period 1860-1880 are more uncertain, because of sparser coverage, than for later periods in the 20th Century. The 1860-1880 period is also only 21 years in length. As for the two periods 1910-40 and 1975-1998 the warming rates are not statistically significantly different (see numbers below).

I have also included the trend over the period 1975 to 2009, which has a very similar trend to the period 1975-1998.

So, in answer to the question, the warming rates for all 4 periods are similar and not statistically significantly different from each other.

Here are the trends and significances for each period:

Next, Monbiot claims that I am wrong to say that 11 of 13 polar bear populations are not declining. The trouble with polar bears is that nobody really knows the truth and lots of different claims are out there. Monbiot cites one study, more recent than the one I relied on, but it's hotly disputed by many. Here is the view of Daniel Shewchuk, environment minister of the Canadian Nunavut territory:

Shewchuk said while the Nunavut government originally agreed with the special-concern listing, it changed its position after consulting with Inuit hunters and others on a recent community tour.

"Through direct consultation, they are unanimous in their belief that polar bears have not declined," Shewchuk said.

Scientists on the committee have argued that although Canada's polar bear population has improved over the last 50 years, the future of the species could be threatened by climate change and receding sea ice.

Furthermore, I know of nobody who disputes the polar bear numbers have hugely increased (from maybe 5,000 to over 20,000) since the 1960s.

Next Monbiot accuses me of `blatant cherry-picking' when I cite examples of how the environment has improved. Here is what I actually said so the reader can judge if I am doing anything other than claiming that `in many places' environmental trends are positive.

` Well all right, says the pessimist, but at what cost? The environment is surely deteriorating. In somewhere like Beijing, maybe. But in many other places, no. In Europe and America rivers, lakes, seas and the air are getting cleaner all the time. The Thames has less sewage and more fish. Lake Erie's water snakes, on the brink of extinction in the 1960s, are now abundant. Bald eagles have boomed. Pasadena has few smogs. Swedish birds' eggs have 75 per cent fewer pollutants in them than in the 1960s. American carbon monoxide emissions from transport are down 75 per cent in 25 years. Today, a car emits less pollution travelling at full speed than a parked car did in 1970 from leaks.

Readers may be curious why I chose Lake Erie's water snakes. Because they were cited by Paul Ehrlich, who himself did research on them, in The Population Bomb in 1968 as follows: 'You see, Lake Erie has died…the snakes are almost gone.' Yet, the US federal government is considering whether to remove the Lake Erie water snake from the endangered list, not because it is extinct, but because its numbers in Ohio have rocketed from less than 2,000 in 1999 to more than 12,000 today.)

Monbiot is entitled to his opinions but he has found precisely zero `excruciating errors' in my book.

Here are a few extracts:

I am going to argue that the ecological footprint of human activity is probably shrinking at an accelerating rate and that we are getting more sustainable, not less, in the way we use the planet. In a nutshell, the most sustainable thing we can do, and the best for the planet, is to accelerate technological change and economic growth.

...

In fact, coming back to my lifestyle, every item that I use today takes less land to produce it than it did in times past. My fleece came out of an oil well, whereas the wool sweater I used to wear on a cold day like this came from a sheep farm. The footprint of the fleece system-well, refinery, factory and shop-is minuscule compared with the land needed for sheep farming. My socks, shoes, shirt and breakfast each take roughly half as many acres to produce as they did before synthetic fertiliser

...

Even semi-luxuries like artificial lighting are experiencing the acreage decline. To keep your home lit with candles of tallow, beeswax or spermaceti oil from whales, or with ancient Babylonian lamps burning sesame oil, would have required many acres of pasture, flowers or seabed. Now it requires a hole in the ground: a surface coal mine produces roughly as much electricity per acre as a field of corn would produce in 2,000 years.

...

So my point is simply this: human land needs-as measured in acres to produce food, acres to produce fibre, fuel, shelter or lighting-are all getting smaller and smaller and have been doing so for a very long time. How then is it possible to argue that we are increasingly and unsustainably overdrawn at the planetary ecological bank?

...

So it is with incredulity that I watch the governments of the world, urged on by greens, assiduously trying to increase the human ecological footprint in the name of saving the planet. They praise organic farming, which means a massive increase in land taken for agriculture. (Don't get me wrong: I don't object to people buying organic; I just object to them telling me it is ethical to do so.) And almost every measure espoused for fighting climate change-wind, waves, solar, tide, hydro and above all biofuels-would increase the acreage required to support a human lifestyle.

If America were to grow all its own transport fuel as biofuel, for example, it would need 30 percent more farmland than it currently uses to grow food. Where would it then grow food? The biofuel boondoggle is a truly awful mistake, a "crime against humanity" in the words of Jean Ziegler, the United Nations special rapporteur on the right to food. Between 2004 and 2007, the world maize harvest increased by 51 million tonnes, but 50 million tonnes went into ethanol, leaving nothing to meet the increase of demand: hence the spike in food prices in 2008, which caused riots andhunger. In effect, American car drivers were taking carbohydrates out of the mouths of the poor to fill their tanks.

...

But in western Europe and eastern Asia-and here's the crucial point-people increase the productivity of the land so much that they actually increase the flow of energy into nature, even while they purloin half of the productivity for themselves. Thanks to the Haber process, in Europe both people and wildlife have more to eat.

This actually gives great cause for optimism, because it implies that intensifying agriculture throughout Africa and central Asia could feed more people and still support more other species, too. [Helmut] Haberl [of the university of Vienna] says: " These findings suggest that, on a global scale, there may be a considerable potential to raise agricultural output without necessarily increasing HANPP."

It contains a charming story, of a Moravian priest called Father Schreiber, who was more interested in horticulture than holiness, and whose parish included Gregor Mendel's birthplace, Hyncice. As Kingsbury tells the tale:

Schreiber also had to face opposition, or at least suspicion, from a conservative peasantry. So in order to distribute new fruit varieties, he and the countess [Maria Walpurga Truchsess-Zeil, no less] developed a technique that has been used more than once down the ages in order to bring new genes to the countryside: subterfuge. A nursery for trees was established and word put out that these valuable seedlings were under guard, the guards being instructed to make a lot of noise if they heard anybody but not to actually arrest anyone. In a matter of days, all the seedlings had been stolen.

Towards the end of his book Kingsbury then gives a much more recent example of the same phenomenon:

In March 2002, following its approval by the Indian government, Mahyco-Monsanto released a number of cotton hybrids containing a gene for the production of a compound lethal to caterpillars, which had been derived from a bacterium. 'Bt cotton' as it was known, was already in cultivation in India - effectively illegally. Since 1998, however, anti-GM activists had been campaigning against the cottton, with Vandana Shiva denouncing them as "seeds of suicide, seeds of slavery, seeds of despair". Farmers, however were desperate to obtain cotton which would not fall victim to bollworm, and to avoid the costs and the dangers of using pesticides. In a situation familiar to producers of software and fashion goods, whereby Asian markets are flooded with fake goods, seeds of the Bt cotton had 'escaped' from Mahyco-Monsanto's test plots, and had been used to breed new 'unofficial' Bt cotton varieties. 'Disappearence' of seeds from test plots is the bane of plant breeders the world over - farmers know that among them are potentially much better plants than the ones they grow. So much for rural conservatism, or indeed the love of traditional landraces.

By 2005, it was estimated that 2.5million hectares were under 'unofficial' Bt cotton, twice the acreage as under the ones which had been sown from Monsanto's packets. The unofficial Bt cotton varieties had been bred, either by companies operating in an ambiguous legal position, or by farmers themselves. A veritable cottage industry had sprung up, a state described as 'anarcho-capitalism', whereby small-scale breeders were crossing reliable local varieties with the caterpillar proof Bt plant. Hundreds of Bt cotton varieties were the result. In other words the worlds first GM landraces had arrived, a blend of tradition and science - something best described as thoroughly post-modern in its eclecticism - and a powerful illustration that old and new technologies can not only co-exist but should both be valued.

Shiva's 'Operation Cremate Monsanto' had spectacularly failed, its anti-GM stance borrowed from western intellectuals having failed to make headway with Indian farmers, who were showing that they were not passive recipients of either technology or propaganda, but taking an active role in shaping their lives. What they did is also perhaps more genuinely subversive of multinational capitalism than anything GM's opponents have ever managed.

In Uganda, GM bananas resistant to black sigatoka disease are grown behind chain-link fences, not to keep eco-toff saboteurs out but to keep eager growers from borrowing the plants.

It's going to happen In Europe too. Fed up with being forbidden by the green zealotry to choose GM crops, a Welsh farmer named Jonathon Harrington last year says that he smuggled insect-resistant maize seeds on to his farm and grew an illegal GM crop.

Here's a letter I just sent to New Scientist:

In her misleading article about my book, among other errors Liz Else wrongly states that I `failed to recognize that there is more to the health of corals than the amount of bicarbonate in the sea'. Yet I clearly state in my book: `take coral reefs, which are suffering horribly from pollution, silt, nutrient runoff and fishing'. After doing the interview, Else asked me for proof of a statement in my book that `Even with tripled bicarbonate concentrations, corals show a continuing increase in both photosynthesis and calcification.' Presumably this was because her unnamed `experts' had challenged this statement. I was happy to supply her with the following extract from Craig Idso's book (`CO2, global warming and coral reefs'), which I cited in my book, and with the reference it cites (Herfort et al 2008. Journal of Phycology 44: 91-98): `This work reveals that additions of HCO3- to synthetic seawater continue to increase the calcification rate of Porites porites until the bicarbonate concentration exceeded three times that of seawater…Similar experiments on Acropora species showed that calcification and photosynthetic rates in these corals were enhanced to an even greater extent, with calcification continuing to increase above a quadrupling of the HCO3- concentration and photosynthesis saturating at triple the concentration of seawater'. I am sorry that instead of quoting this exchange between us, Else chose to fall back on unsubstantiated accusations of `misconceptions, selective reporting and failure to see the significance of historical changes in ocean acidity'. I took the trouble to back up my claims; she should have done so for her accusations.

I will write more about ocean acidity soon. It's shocking how few people realise that raising seawater acidity with carbonic acid has very different effects from raising it with hydrochloric acid.

Take coral reefs, which are suffering horribly from pollution, silt, nutrient run-off and fishing - especially the harvesting of herbivorous fishes that otherwise keep reefs clean of algae. Yet environmentalists commonly talk as if climate change is a far greater threat than these, and they are cranking up the apocalyptic statements just as they did wrongly about forests and acid rain

Andy Ridgwell says `I agree that at least for some reef systems, other, and more local human factors such as fishing and pollution may be the greater danger' and Jelle Bijma says `I do agree that, for example, pollution and overfishing are also important problems, some even more important than the current impact of ocean acidification'. It was not therefore accurate of Liz Else to say that the critics accuse me of failing `to recognize that there is more to the health of corals than the amount of bicarbonate in the sea' They do not - she has misrepresented their views and mine.

Charlie Veron, an Australian marine biologist: 'There is no hope of reefs surviving to even mid-century in any form that we now recognise.' Alex Rogers of the Zoological Society of London pledges an 'absolute guarantee of their annihilation'. No wriggle room there.

Chris Langdon agrees that such claims `may be extreme'. None of the others provides any evidence to support such extreme claims. Yet these remarks were widely reported in the media.

It is true that rapidly heating the water by a few degrees can devastate reefs by 'bleaching' out the corals' symbiotic algae, as happened to many reefs in the especially warm El Niño year of 1998. But bleaching depends more on rate of change than absolute temperature. This must be true because nowhere on the planet, not even in the Persian Gulf where water temperatures reach 35°C, is there a sea too warm for coral reefs.

Ove Hoegh-Guldberg says that `the observation that corals grow in the Persian Gulf today at temperatures of 35 °C does not mean that coral reefs will be able to adapt rapidly to the current upward shift in sea temperatures' in other words, he concedes the point I was actually making: bleaching is caused by rate of change of temperature, not absolute level of warmth. This is not understood by many commentators on the subject in both the environmental movement and the media. I am glad to have it confirmed, because it corrects a widespread misunderstanding.

Lots of places are too cold for coral reefs - the Galapagos, for example.

Ridgwell says that `There are in fact several reef communities in the Galapagos, so the inference that the Galapagos is "too cold" is incorrect (or at best, mis-interpretable), although I agree that colder temperatures are likely an important factor in the dominance of non-reef coral communities in this location.' Which is it? `Incorrect' or `an important factor'? He concedes my point in his last phrase: `the dominance of non-reef coral communities in this location.' The very few reefs are in the warmer parts of the Galapagos. Incidentally, Charles Darwin once wrote: `There are no coral-reefs in the Galapagos Archipelago, as I know from personal inspection'.

It is now clear that corals rebound quickly from bleaching episodes, repopulating dead reefs in just a few years,

None of the five challenge this statement. As an example, a study of Fiji's reefs following a bleaching episode (Lovell and Sykes 2008. International Coral Reef Symposium) states: `Though variable, substantial recovery to pre-bleaching levels was seen within 5 years in many areas.'

which is presumably how they survived the warming lurches at the end of the last ice age.

Both Ridgwell and Hoegh-Guldberg claim that current rates of temperature change are unprecedented. Ridgwell says that the deglacial transition `was a few degrees centigrade in about 4000 to 5000 years. In the future, we are looking at a few degrees in a hundred years - perhaps 50 times faster (certainly, one to two orders of magnitude higher).' Hoegh-Guldberg refers to a rate of change `that is many times higher than even the most rapid shifts in conditions seen over the past million years or more.' These are astonishing statements to anybody with even a cursory knowledge of the scientific literature on the ending of the last ice age. The current rate of temperature change since 1975 is estimated at about 0.161 degC per decade (and is incidentally not statistically distinguishable from that in the 1860-1880 or 1910-1940 periods - see Roger Harrabin's interview with Phil Jones here:http://news.bbc.co.uk/1/hi/sci/tech/8511670.stm). By contrast the deglacial transition was characterized by `local, regional, and more-widespread climate conditions [which] demonstrate that much of the Earth experienced abrupt climate changes synchronous with Greenland within thirty years or less' (Alley 2000. Quaternary Science Reviews 213-226), including `a warming of 7 °C in South Greenland [that] was completed in about 50 years' (Dansgaard, White and Johnsen 1989, Nature 339: 532). That is a change roughly nine times as fast as has happened since 1980 - in Greenland or anywhere else. Another study gives even bigger numbers, saying that the `abrupt warming (10 ± 4 °C)' at the end of the Younger Dryas and the warming at the end of a short lived cooler interval known as the Preboreal Oscillation `may have occurred within a few years' (Kobashi et al 2008 Earth and Planetary Sciences 268:397). Nor was this rate of change confined to Greenland. As one article summarises, `temperatures  from the end of the Younger Dryas Period to the beginning of the Holocene some 12,500 years ago rose about 20 degrees Fahrenheit in a 50-year period in Antarctica, much of it in several major leaps lasting less than a decade.' (Science Daily, Oct 2 1998). It is remarkable how few scientists working on other aspects of planetary ecology seem to know about these recent conclusions of much faster changes in the past. No climatologist would these days claim that current rates of change are unprecedented in `the past million years or more'.

It is also apparent from recent research that corals become more resilient the more they experience sudden warmings.

None of the five challenges this statement, which is based on a paper by Oliver and Palumbi 2009 (MEPS 378:93), which concluded that corals are `tougher than we thought' (interview with Science News May 22, 2009) and on Baker et al 2004 (Nature 430:741), who say: 'The adaptive shift in symbiont communities indicates that these devastated reefs could be more resistant to future thermal stress, resulting in significantly longer extinction times for surviving corals than had been previously assumed.'

Some reefs may yet die if the world warms rapidly in the twenty-first century, but others in cooler regions may expand.

Ridgwell agrees `that eventual colonisation and expansion of corals into regions previously too cold will, in theory, be possible at some point in the future' so there is no inaccuracy in my statement. He merely says that it is `unclear' whether dispersal and colonisation can occur fast enough to keep up with increasing temperatures.

Local threats are far more immediate than climate change.

Ridgwell agrees `that at least for some reef systems, other, and more local human factors such as fishing and pollution may be the greater danger' but says this may not be true for those in protected areas - because the local threats there have been reduced. That is merely a statement of the obvious. But the greatest threats to coral reefs come outside protected areas.

Ocean acidification looks suspiciously like a back-up plan by the environmental pressure groups in case the climate fails to warm: another try at condemning fossil fuels.

A statement of my opinion based on what follows.

The oceans are alkaline, with an average pH of about 8.1, well above neutral (7).

Langdon confirms this: `Yes, it is true that the surface oceans are slightly alkaline at a pH of 8.1' but then says that `the declining pH of the surface ocean is one of the most firmly established facts in climate change science.' Is he implying that I dispute this? I do not. Incidentally, the pH of the ocean varies hugely, being below neutral in some inshore areas influenced by run off from the land. On some coral reefs it goes as low as 7.5 at night and as high as 9.4 in the day (Revelle and Fairbridge 1957). Remarkably there are parts of the sea with pH already far lower than it can possibly go as a result of carbon emissions. In one hydrothermal spot off Iceland, it is 5.36-7.29.Yet four-decade-old mussels have learned to cope with even this acidity, though growing half as fast as in normal waters (Tunnicliffe et al 2009, Nature Geoscience 10.1038).

They are also extremely well buffered.

Langdon agrees: `And yes, the oceans are well buffered'.

Very high carbon dioxide levels could push that number down, perhaps to about 7.95 by 2050 - still highly alkaline

Presumably it is here that Bijma thinks I `introduce confusion about the term "acidification"' merely because by saying that 7.95 is still highly alkaline, I am accurately reminding the reader that there is no prediction of the oceans becoming technically `acid' - ie having a pH lower than 7. Far from introducing confusion, I was attempting to reduce the very confusion so often encountered by readers who think that acidification will lead to oceans that are actually acid. In any case, my statement is accurate.

and still much higher than it was for most of the last 100 million years.

Ridgwell agrees: `Ocean pH in the past (at least, according to published reconstructions) was indeed lower than now during the Cretaceous, and probably lower than anything we will manage in the future.'

Some argue that this tiny downward shift in average alkalinity could make it harder for animals and plants that deposit calcium carbonate in their skeletons to do so. But this flies in the face of chemistry: the reason the acidity is increasing is that the dissolved bicarbonate is increasing too -

Langdon agrees: `Matt is correct that bicarbonate concentrations are increasing'.

and increasing the bicarbonate concentration increases the ease with which carbonate can be precipitated out with calcium by creatures that seek to do so.

Here there seems superficially to be a disagreement, but in reality there is none. Ridgwell, Langdon and Bijma say that carbonate levels fall rather than rise as a result of increasing dissolved carbon dioxide. But I don't say that carbonate levels rise. I say that the biological precipitation of carbonate by organisms is easier at higher bicarbonate levels. And Langdon confirms this: `Matt is correct that the skeleton and shell building of some species is unaffected or even increases under reduced pH'. My evidence? For example, Ries et al 2009 (Geology37:1131) found that in seven of the 18 species of calcifiers they observed `net calcification increased under the intermediateand/or highest levels of pCO2'. And that their results `suggestthat the impact of elevated atmospheric pCO2 on marine calcificationis more varied than previously thought, while Hendriks et al 2010 (Estuarine, Coastal and Shelf Science 86:157) found that  the ion chemistry inside the bodies of calcifiers is more important than that outside them, and there is evidence that some of them - eg coccolithophores - actually find it energetically easier to deposit carbonate shells at slightly lower pH.

Even with tripled bicarbonate concentrations, corals show a continuing increase in both photosynthesis and calcification.

My source was the Herfort et al 2008 paper, which Ridgwell says is irrelevant, because of its experimental design. That's his opinion, which others in the field do not share. In any case, my statement was a correct and precise description of the result.

This is confirmed by a rash of empirical studies showing that increased carbonic acid either has no effect or actually increases the growth of calcareous plankton, cuttlefish larvae and coccolithophores.

Hoegh-Guldberg disagrees: `Call it inconvenient but the vast bulk of scientific evidence shows that marine calcifiers such as coccolithophores, corals and oysters are being heavily impacted already by ocean acidification.' He provides no reference. By contrast, I cite Iglesias-Rodriguez et al 2008 (Science 320:336). They state: `From the mid-Mesozoic, coccolithophores have beenmajor calcium carbonate producers in the world's oceans, todayaccounting for about a third of the total marine CaCO3production.Here, we present laboratory evidence that calcification andnet primary production in the coccolithophore species Emilianiahuxleyi are significantly increased by high CO2 partial pressures.Field evidence from the deep ocean is consistent with theselaboratory conclusions, indicating that over the past 220 yearsthere has been a 40% increase in average coccolith mass'.

As for oysters, Miller et al. 2009 (PLOS ONE 4: 10.1371) found that oyster larvae `appeared to grow, calcify and develop normally with no obvious morphological deformities, despite conditions of significant aragonite undersaturation,' and that these findings `run counter to expectations that aragonite shelled larvae should be especially prone to dissolution at high pCO2'.

As for sea urchins, Lacoue-Labarthe et al. 2009 (Biogeosciences 6)  report that `decreasing pH resulted in higher egg weight at the end of development at both temperatures (p < 0.05), with maximal values at pH 7.85 (1.60 ± 0.21 g and 1.83 ± 0.12 g at 16°C and 19°C, respectively).'.

As for corals, Suwa et al. 2010 (Fisheries science 76) report that `larval survival rate did not differ significantly among pH treatments.'

Lest my critics still accuse me of cherry-picking studies, let me refer them also to the results of Hendrikset al. (2010, Estuarine, Coastal and Shelf Science 86:157). Far from being a cherry-picked study, this is a massive meta-analysis. The authors observed that `warnings that ocean acidification is a major threat to marine biodiversity are largely based on the analysis of predicted changes in ocean chemical fields' rather than empirical data. So they constructed a database of 372 studies in which the responses of 44 different marine species to ocean acidification induced by equilibrating seawater with CO2-enriched air had been actually measured. They found that only a minority of studies demonstrated `significant responses to acidification' and there was no significant mean effect even in these studies. They concluded that the world's marine biota are `more resistant to ocean acidification than suggested by pessimistic predictions identifying ocean acidification as a major threat to marine biodiversity' and that ocean acidification `may not be the widespread problem conjured into the 21st century…Biological processes can provide homeostasis against changes in pH in bulk waters of the range predicted during the 21st century.' This important paper alone contradicts Hoegh-Gudlberg's assertion that `the vast bulk of scientific evidence shows that calcifiers… are being heavily impacted already'.

In conclusion, I rest my case. My five critics have not only failed to contradict, but have explicitly confirmed the truth of every single one of my factual statements. We differ only in how we interpret the facts. It is hardly surprising that my opinion is not shared by five scientists whose research grants depend on funding agencies being persuaded that there will be a severe and rapid impact of carbon dioxide emissions on coral reefs in coming decades. I merely report accurately that the latest empirical and theoretical research suggests that the likely impact has been exaggerated.

When I joined the Economist in 1983, Norman Macrae was the deputy editor. He died last week at the age of 87. Soon after I joined the staff, a thing called a computer terminal appeared on my desk and my electric typewriter disappeared. Around that time, Norman wrote a long article that became a book about the future. It was one of the strangest things I had ever read.

It had boundless optimism --

Over the last decade, I have written many articles in The Economist and delivered lectures in nearly 30 countries across the world saying the future should be much more rosy. This book explores the lovely future people could have if only all democrats made the right decisions.

combined with a weird technological vision --

Eventually books, files, television programmes, computer information and telecommunications will merge. We'll have this portable object which is a television screen with first a typewriter, later a voice activator attached. Afterwards it will be minaturised so that your personal access instrument can be carried in your buttonhole, but there will be these cheap terminals around everywhere, more widely than telephones of 1984. The terminals will be used to access databases anywhere in the globe, and will become the brainworker's mobile place of work. Brainworkers, which will increasingly mean all workers, will be able to live in Tahiti if they want to and telecommute daily to the New York or Tokyo or Hamburg office through which they work. In the satellite age costs of transmission will not depend mainly on distance. And knowledge once digitalised can be replicated for use anywhere almost instantly.

and a startlingly fresh economic perspective --

In the 1890s around half of the workforce in countries like the United States were in three occupations: agriculture, domestic service and jobs to do with horse transport. By the 1970s these three were down to 4 per cent of the workforce. If this had been foretold in the 1890s, there would have been a wail. It would have been said that half the population was fit only to be farmworkers, parlourmaids and sweepers-up of horse manure. Where would this half find jobs? The answer was by the 1970s the majority of them were much more fully employed ( because more married women joined the workforce) doing jobs that would have sounded double-Dutch in the 1890s: extracting oil instead of fish out of the North Sea; working as computer programmers, or as television engineers, or as package-holiday tour operators chartering jet aircraft.

When he retired in 1988 he wrote

Some will say [I have] been too optimistic. That is what a 65-year-old like me finds it natural to be. When I joined The Economist in 1949 it seemed unlikely that the world would last long. But here we stand, 40 memory-sodden years on, and what have we done? What we have done - largely because the poorest two-thirds of people are living much longer - is approximately to octuple real gross world product. During the brief civilian working lives of us returning soldiers from the second world war, we have added seven times as much to the world's producing power as was added during all the previous millennia of homo sapien's existence. That may help to explain why some of us sound and write rather tired. It does not explain why anybody in the next generation, to whom we gladly vacate our posts, can dare to sound pessimistic.

He was a rational optimist.

As one goes from Hawaii to Alaska the pH slowly decreases along the transect, dropping from 8.05 all the way down to 7.65. This is a change in pH of almost half a unit.

The study also measured the change caused by carbon dioxide from industry:

The maximum anthropogenic change [at the surface] over the entire transect was -0.03 pH in fifteen years. The average anthropogenic change over the top 150 metre depth was -0.023. From there down to 800 metres the average anthropogenic change was -0.011 in fifteen years.

In other words,

That means that at the current rate of change, the surface water in Hawaii will be as alkaline as the current Alaskan surface water in … well … um … lessee, divide by eleventeen, carry the quadratic resdual … I get a figure of 566 years. But of course, that is assuming that there would not be any mixing of the water during that half-millennium.

Eschenbach coincidentally uses much the same words as I did about ocean acidification:

My conclusion? To mis-quote Mark Twain, "The reports of the ocean's death have been greatly exaggerated."

One of Eschenbach's readers then points out (don't you love the way information can meet on the web?) that the pH of the water entering the Monterey Bay aquarium has been measured for many years and:

the sea creatures in the Monterey Bay can easily withstand a change in pH of 0.5 in the course of a single month.

Dr. Mitani's team has now put a full picture together by following chimps on their patrols, witnessing 18 fatal attacks over 10 years and establishing that the warfare led to annexation of a neighbor's territory.

The fact that male chimpanzees systematically and stealthily patrol their boundaries in groups to kill neighbouring males has been known for a long time in Gombe in Tanzania, but critics have charged that it was unnaturally caused by human feeding of the chimps. That now seems unlikely.

This catches my attention because it explains how hard it must have been to invent trade between groups. If your only contact with other groups was homicidal how do you ever suggest swapping food or tools instead? I am often asked why, if trade is so valuable, did other species not adopt it, Neanderthals especially.

My answer is that getting past this warfare habit was a big hurdle.

Neanderthals did not manage it, as witnessed by their reliance on local rather than imported stone for their tools.

`We Africans' did get over this hurdle. How? I don't know. It might have been serendipity, or it might have been because we pre-conditioned ourselves to working for each other through the invention of the sexual division of labour.

Why did not females, who don't take part in warfare, invent trade behind males' backs?

Our adversaries consider that an activity which is neither aided by supplies, nor regulated by government, is an activity destroyed. We think just the contrary. Their faith is in the legislator, not in mankind; ours is in mankind, not in the legislator.

The latest evidence for the rationality of such optimism can, of course, be found in my book.

I am a judge for this year's Bastiat Prize for Journalism, which rewards modern-day writers in his spirit. Entries must be in by 30 June, so there are still a few days left to enter. Entry form and full details here: http://www.policynetwork.net/bastiat-2010-announcement

But it was the details that stole the show. The lack of sharpening on the rear of the canines (unlike a chimpanzee), the flared pelvis of a regular biped, the curved but relative short metatarsals of the foot, the hints of very little sexual dimorphism.

The ecology, too, is intriguing. The Afar depression was not such a depression then, and the weather was sufficiently damp for a fairly rich forest to be growing there, albeit with patches of grassland. By far the commonest antelopes were woodland-dwelling, browsing kudu. Ardi herself ate fruits and nuts from trees, not grasses -- this can be decided by isotopic analysis -- and she was a good climber as well as a walker. Her molar teeth had not grown robust like those of Lucy, for grinding grass seeds and roots, but nor had they shrunk for processing soft fruit as those of modern chimpanzees have.

Nobody quite knows where it fits in the family tree. White reckons it post-dates the split with chimpanzees and lies on our line, because it had features shared with human beings that chimps lack -- it was a good biped for example:

Ar. ramidus indicates that despite the genetic similarities of living humans and chimpanzees, the ancestor we last shared probably differed substantially from any extant African ape. Hominids and extant African apes have each become highly specialized through very different evolutionary pathways.

Others argue it might pre-date the split, on the grounds that the molecular clock points to a divergence at around 3-5 million years ago. This disagreement has already grown quite testy, though I cannot really see why: it just seems to be the pattern in academia at the moment.

White has also been sharply criticised by primatologists, some of whom hate his conclusion that chimpanzees have done a lot of evolving since the split -- or to put it another way, that in certain features the last common ancestor resembled us more than it resembled chimps. This -- to me obvious -- point upsets them because they think it undermines their claim that studying and conserving chimpanzees is justified as a study of what our ancestors must have been like.

That's weird. Study chimps to find out what a modern ape does, not as a form of self-obsession. Conserve it because it is rare, beautiful and fascinating, not out of narcissism.

Ardipithecus is a wonderful glimpse of the past. It's somewhere pretty close to the missing link, and it's interesting in its own right.

Just as I uttered the words "of course, things will still go wrong", there was a huge thunderclap, the lights went out and the slide projector died.

Last week a study claimed that 97-98 percent of the most published climate scientists agree with the scientific consensus that man-made climate change is happening.

Well, duh. Of course they would: it's their livelihood. Anyway, so do I. So do most `sceptics': they just argue about how much and through what means. You can believe in man-made carbon dioxide causing man-made climate change but not in net positive feedbacks so you think the change will be mild, slow, hard to discern among natural changes and far less likely to cause harm than carbon-rationing policies: that's still within the range of possibilities of the IPCC consensus.

Besides, what happened to previous declarations of certain scientific consensus? In Reason magazineRon Bailey has gone back and looked up the phrase in the mainstream media before 1985. He finds that it was used about a whole bunch of assertions that later proved false, exaggerated or misleading

First saccharin:

One of the first instances of the uses of the phrase appears in the July 1, 1979 issue of TheWashington Poston the safety of the artificial sweetener saccharin. "The real issue raised by saccharin is not whether it causes cancer (there is now a broad scientific consensus that it does)"

Yet

Thirty years later, the National Cancer Institute reportsthat "there is no clear evidence that saccharin causes cancer in humans.

Second dietary cancer:

Similarly, the Postreported later that same year (October 6, 1979) a "profound shift" in the prevailing scientific consensus about the causes of cancer. According to thePost, researchers in the 1960s believed that most cancers were caused by viruses, but now diet was considered the far more important factor. One of the more important findings was that increased dietary fiber appeared to reduce significantly the incidence of colon cancer.

Yet

Twenty years later, a major prospective studyof nearly 90,000 women reported, "No significant association between fiber intake and the risk of colorectal adenoma was found." In 2005, another big study confirmedthat "high dietary fiber intake was not associated with a reduced risk of colorectal cancer."

Third, fusion:

The December 17, 1979 issue of Newsweekreported that the Department of Energy was boosting research spending on fusion energy reactors based on a scientific consensus that the break-even point-that a fusion reactor would produce more energy than it consumes-could be passed within five years.

Yet

That hasn't happened yet and the latest effort to spark a fusion energy revolution, the International Thermonuclear Experimental Reactor, will not be ready for full-scale testing until 2026.

Fourth, acid rain:

The March 10, 1985 New York Timescited environmental lawyer Richard Ottinger, who asserted that there is a "broad scientific consensus'' that acid rain is destroying lakes and forests and ''is a threat to our health.''

Yet

The [official] assessment concluded that acid rain was not damaging forests, did not hurt crops, and caused no measurable health problems. The report also concluded that acid rain helped acidify only a fraction of Northeastern lakes and that the number of acid lakes had not increased since 1980.

Had he been able to go back further in time, Bailey would have found just as firm a scientific consensus behind eugenics.

Of course, some assessments are right. And of course, the environmentalists most loudly proclaiming that we must obey the scientific consensus on climate change take no such notice of the consensus that genetically modified crops are safe.

I now see at firsthand how I avoided hearing any good news when I was young. Where are the pressure groups that have an interest in telling the good news? They do not exist. By contrast, the behemoths of bad news, such as Greenpeace, Friends of the Earth and WWF, spend hundreds of millions of dollars a year and doom is their best fund-raiser. Where is the news media's interest in checking out how pessimists' predictions panned out before? There is none. By my count, Lester Brown has now predicted a turning point in the rise of agricultural yields six times since 1974, and been wrong each time. Paul Ehrlich has been predicting mass starvation and mass cancer for 40 years. He still predicts that `the world is coming to a turning point'.

In short, futures allow speculation upon the future: which is why we have them, for speculation upon the future allows us to sidestep the very things which we do not desire to happen in that future.

Now, of course, you could design an alternative method of doing this. The wise, omniscient and altruistic  politicians and bureaucrats could send a fax to all farmers telling them to plant more. Signs could appear in every breadshop telling us all to eat our crusts.

Except, of course, those wise, omniscient and altruistic politicians and bureaucrats are precisely the fuckers that got us into the mess in the first place by insisting that we should put wheat into cars rather than people.

Rob Bradley has a superb series of posts on how it was not just greedy speculation, but also greenie politicking that got BP and Enron into trouble. I particularly treasure this quotation from the celebrity environmentalist Lester Brown in 1998:

"Within the fossil fuel industry itself … some companies such as Enron, British Petroleum, and Royal Dutch Shell are already looking to the future, and beginning to invest in alternative energy sources. Enron's chairman, Ken Lay, who publicly discusses the need to reduce carbon emissions and to stabilize climate, sees Enron at the heart of the transition from fossil fuels to renewable energy sources. The infrastructure it has built to store and distribute natural gas can one day be used for hydrogen as the solar/hydrogen economy unfolds…In an important speech at Stanford University in May 1997, British Petroleum's CEO, John Browne, said: 'The time to consider the policy dimensions of climate change is not when the link between greenhouse gases and climate change is conclusively proven, but when the possibility cannot be discounted and is taken seriously by the society of which we are a part. We in BP have reached that point.' This was a big jump for big oil."

Says Bradley:

Just imagine if John Brownehad used the time and resources BP spent on climate alarmism and 'beyond petroleum' on real safety and environmental issues.

BP might still have a capitalization of $150 billion and not face a potential worst-case scenario of bankruptcy and ruin. And more importantly, the U.S. Gulf would not be in an environmental crisis.

Just imagine if Enron's Ken Lay had used the time and resources spent on climate alarmism and forced energy transformationon accounting, risk control, and the real things that promote business sustainability. (Lay was a big Christopher Flavin/Worldwatch fantoo.)

Enron might still be with us today.

Diverted management attention has an opportunity cost. Left environmentalists lobbied and praised BP and Enron for putting form over substance. A few shouted 'greenwashing', but most applauded their coveted split within the fossil-fuel industry on climate and energy.

Enron is no longer around. Instead it has become the poster child of political capitalism run amuck. And the Deepwater Horizon accident-for which, in an effort to save about $5 million, BP will pay tens of billions of dollars-may sink BP as an independent company.

WHEN I was growing up in the 1970s we were warned the ice age was returning, the population explosion was unstoppable and we'd all be poisoned by chemicals in the environment.

None of these things happened.

In fact, all the trends went in the opposite direction - our lives actually got better. We're happier, healthier, richer and kinder than we were 50 years ago.

1. More than almost any nation since the Phoenicians, the Dutch traded rather than plundered their way to prosperity in their Golden Age.

2. They were cheated out of winning (hosting?) the industrial revolution by invasions and attacks from jealous neighbours, especially Louis XIV.

3. When thwarted at home they took their trade model to Britain by taking over the monarchy in the Glorious Revolution and installing merchant-friendly policies.

4. Their trade created some of the most sublime works of art of all time. Rembrandt and Verneer would not have happened without trade and prosperity.

5. They founded New York.

6. Despite having one of the highest population densities in the world, they are encouraging biodiversity. They may even manage to recreate the aurochs.

7. They suffered terribly in the Hunger Winter for standing up the Nazis.

8. They are living proof to climate pessimists that dwelling below sea level is no problem if you are prosperous.

9. They discovered Spitsbergen, the last land mass in the Northern hemisphere to be discovered by human beings

10. They have yet to win the World Cup.

People who ask the world to spend $45 trillion on a project are surely under an obligation to show their raw data and their workings. If instead, they

publish only `adjusted data' rather than raw data,

refuse reasonable requests for computer code,

break freedom of information laws,

use `tricks' to `hide' inconvenient data,

base an argument on one tree,

use inappropriate statistical techniques,

break their own rules on sources,

and urge each other to delete rather than release correspondence,

then I don't think they should go to jail or be called frauds.

But I do think their request should be politely turned down.

It shows the media mentions of scares, all of them false alarms. Notice the huge peaks for swine flu and bird flu. Notice how video game fears peak twice a year, once in November when video games are released and once in April, the anniversary of the 1999 Columbine massacre. Notice the Y2K peak. Notice that mad cow disease re-emerges in 2003, the year when human deaths rose again after falling for a number of years -- by one (from 17 to 18).

Notice above all the disapperance of such scare stories  for a while -- in September 2001.

At TEDGlobal 2010, author Matt Ridley shows how, throughout history, the engine of human progress has been the meeting and mating of ideas to make new ideas. It's not important how clever individuals are, he says; what really matters is how smart the collective brain is.

So long as the cap holds, and assuming that is the end of it, the Deepwater Horizon spill (up to 600,000 tonnes in total) will now take its place in the oil spill hall of shame. BP's cavalier incompetence has made this probably the worst oil-spill year since 1979, the year that saw not only the previous worst rig spill - the Ixtoc 1 platform off Mexico - but also the worst tanker spill, a collision of two supertankers off Trinidad.

All this, just when things were going so well in the oil-spill business. The number and collective size of oil spills (over 7,000 tonnes) has declined in each of the last four decades, from 25 large spills and over 250,000 tonnes a year in 1970-1979 to three spills and about 20,000 tonnes a year in 2000-2009: that is a drop of more than 90%.

No wonder the other oil companies are livid with BP, a company that spent the last decade and a half burnishing its reputation as an environmental paragon, apparently to the detriment of its capacity to manage old-fashioned oil production safely. `Within the fossil fuel industry itself,' said the prominent environmentalist Lester Brown in 1998, `some companies such as Enron, British Petroleum, and ... are already looking to the future, and beginning to invest in alternative energy sources.' It seems unkind to curse the third firm he mentioned by naming it, but let's call it Scallop.

The clean-up will be long and difficult, and the effects of the spill will be felt for a long time in the pensions of Britons, the priorities of politicians and regulators as well as the pelicans of the Gulf. So it might be a good idea to learn lessons from previous oil spill clean-ups. Some of these are surprising.

First, be careful not to do more harm than good. When the Torrey Canyon was wrecked off Cornwall in 1967, spilling 120,000 tonnes of oil, the British government not only bombed the wreck (and missed with one bomb in four), but sprayed 10,000 tons of detergents, which were much more damaging to marine life than the oil itself, then bulldozed the oil and detergents into the sand on some beaches where it persisted for longer than if it had been exposed to the elements.

The mistake was repeated in 1989, when the Exxon Valdez spilled about 40,000 tonnes in Prince William Sound. Thousands of volunteers were sent out to wash rocks with hot water, which helped kill lots of microbes that would otherwise have eaten the oil.

Speaking of microbes, do not underestimate nature's powers of recovery. After most big oil spills, scientists are pleasantly surprised by how quickly the oil disappears and the marine life reappears. This is true even in Alaska, where the sheltered waters, low temperatures and abundant wildlife conspired to make the slick damaging and persistent. The National Oceanic and Atmospheric Administrationsays on its website: `What scientists have found is that, despite the gloomy outlook in 1989, the intertidal habitats of Prince William Sound have proved to be surprisingly resilient.' A scientist who led some of the research into the Exxon Valdez says that `Thoughts that this is going to kill the Gulf of Mexico are just wild overreactions'.

When the Braer went aground off Shetland in 1993 and spilled 85,000 tonnes of oil, storms quickly dispersed the oil, so the effect on most of the local wildlife was barely measurable. As one scientific report drily noted, after running through a list of undetected effects on birds, shore life and seabed creatures, `five otters were found dead in the oil spill area. However, three of these were killed by vehicles, one was recovered before the oil could have reached it and the cause of mortality of the fifth did not appear to be oil contamination.' (One of the road kills was allegedly caused by a television crew's car.)

This rapid recovery was also a signature of the last big Gulf rig spill, the Ixtoc 1 disaster off Mexico in 1979. Although the number of turtles took decades to recover, much of the rest of the wildlife bounced back fairly rapidly. `To be honest, considering the magnitude of the spill, we thought the Ixtoc spill was going to have catastrophic effects for decades', Luis Soto of the National Autonomous University of Mexico told a newspaper this year. `But within a couple of years, almost everything was close to 100 percent normal again.' The warm waters and strong sunshine of the Gulf of Mexico are highly conducive to the chemical decomposition of oil by `photo-oxidation', and are stuffed full of organisms that actually like to eat the stuff - in moderation.

Indeed, the sea floor in the Gulf is rich in `cold seeps' -- communities of tube worms and other organisms that live off oil naturally seeping from beneath the seabed. (The annual flow of oil through such seeps is about half the total spill.) Hundreds of these clusters of clams and tube worms have been found since the 1980s in the deep waters of the Gulf of Mexico, living off the microbes that eat the oil.

Such ecosystems are not equipped to cope with being inundated with so much oil even if it is their food, but one Texas scientist told the New York Times that `the gulf is such a great fishery because it's fed organic matter from oil...it's pre-adapted to crude oil. The image of this spill being a complete disaster is not true.'

Another lesson to learn is that the media covers the disaster and not the recovery. When the Sea Empress spilled 70,000 tonnes of oil off Pembrokeshire in 1996, the oil was quickly dispersed. The impact on the 500,000 pairs of birds that breed nearby was relatively small, but the impact on the 500,000 tourists who normally visited the beaches of Pembrokeshire each year- and the businesses that relied on them - was dire. In about a year Louisiana's tourist businesses will be protesting that their beaches are now clean and would the tourists please come back, but the media will largely ignore them. Good news is no news.

The final lesson is that the environmental threats that matter are the slow, continuous ones, not the telegenic sensations like oil spills. BP's spill is known to have killed just over 1,300 birds so far. Just one wind farm, at Altamont Pass in California, was until recently known to kill perhaps 1,300 birds of prey every year. If BP really wants to kill birds, it should indeed go beyond petroleum and into wind, an industry that kills far more rare birds per joule of energy produced than oil does.

What he does especially well is to point out how conservative, how elitist and anti-aspirational, so many of the critics of economic growth are. In a fascinating chapter he explores the way in which the Left has abandoned the idea of progress, and turned conservative:

Nowadays it has reached the stage where what passes for radical thinking is typically imbued with deep social pessimism and hostility to economic growth. Paradoxically, to the extent that any current is associated with advocating prosperity, it is often the free market Right.

Ben-Ami's chapter on happiness research is especially enlightening. He points out that not only are its basic empirical assumptions deeply flawed -- most people are happy, happiness does correlate with prosperity and the paradox of mental illness engendered by affluence is merely an artefact of steadily widening definitions of mental illness - but its aims are reactionary and misanthropic:

The underlying message of the happiness movement is deeply conservative: be happy with what you have got. Such an outlook is entirely consistent with elitist defence of privilege that characterises growth scepticism more generally.

(I have always liked Gregg Easterbrook's comment on happiness research:

Researching this book, and thinking about the alternatives, has caused me to begin whispering a regular prayer of thanks. Thank you that I and five hundred million others are well-housed, well-supplied, over-fed, free and not content; because we might be starving, wretched, locked under tyranny, and equally not content.)

Ben-Ami ends with a powerful call to rehabilitate growth as a goal for humanity:

Growth scepticism is in many respects the opposite to what most of its supporters assume it to be. They typically see it as humane, egalitarian, radical, respectful of the environment and scornful of the obsession with consumption in western societies. But it is inhumane, elitist, conservative, misanthropic and more preoccupied with consumption than anything else. If our great grandparents were alive today they would be astonished by our lack of gratitude...

This is an important and original book.

What I notice is that when I write about this, I have to correct a lot of false claims about what the anti-floresiensis scientists have said. Why do I so rarely have to correct false claims about what the pro-floresiensis scientists say? This is a generalization, but I've written enough about this to have a good impression. The media reports skeptical arguments very poorly. I think it's a systematic problem with science writing.

With the H. floresiensis issue, the science writers have been abetted by some careless scholars. A reporter may quote a pro-floresiensis scientist who says his critics believe something totally nonsensical, and they report that uncritically. This is another example of the same. I challenge anybody to find an anti-floresiensis scholar who has written that "nature moves inexorably towards bigger brains".

Hawks is dead right on both points. First, sceptical arguments get caricatured most; second, this is because people don't read the views they don't agree with. Instead they read their friends' caricatures of their enemies' arguments. This is the story of the Nature-Nurture debate over many decades, where the orthdox scientific church -- which insisted that nurture was all -- indulged in furious denunciations of straw men genetic determinists based on only reading their friends' versions of what their enemies said. The opposite sometimes happened as well but not so much.

The point applies especially to climate science today. If you try to find rebuttals of heretic climate sceptics, again and again you find yourself wading through articles attacking straw men that bear little resemblance to the sceptics' actual arguments. I have yet to read a defence of the hockey stick graph, for example, that understands, let alone does justice to, Steve McIntyre's critique before dismissing it. RealClimate is an egregious offender in this regard.

The Muir Russell report employed the straw man technique, as related by McIntyre:

Unfortunately, Monbiot and others had uncritically accepted disinformation from the Muir Russell inquiry, which, on this point (as on some others), instead of examining (with citations) actual criticisms from sources like Climate Audit, preferred instead to construct its own allegations which, in this case, they described as "broad allegations which are prevalent in the public domain"

The straw man allegation in question is that the CRU distorted the temperature data it got from the stations to show false warming -- something NASA genuinely stands accused of. It's not clear if CRU has ever been accused of that at least by any of the critics attacked in the emails. The actual McIntyre allegation is that the CRU refused to divulge what it did to the raw data it was paid so much to collate, and that it apparently failed to adjust the data for urban heat islands. Weirdly, it seems the Russell report writers could not bring themselves to read McIntyre's actual writings, or at least not carefully.

Andrew Revkin does something similar re the hockey stick, as discussed here by Bishop Hill, describing the criticisms of the graph in inaccurate terms.

If you disagree with somebody, always take the trouble to read your target's actual words and rebut what he actually said, not what you say he said. It is amazing how few do this. I am sure I have been guilty of this in the past, too.

Bryce calculates that one Texas nuclear plant generates about 56 watts per square metre. This compares with 53 for gas turbines, 1.2 for wind, 6.7 for solar or 0.05 for corn ethanol. Sorry, but what is so green about using 45 times as much land - and ten times as much steel - to produce the same amount of power? It does not surprise me that those with vested interest in renewables close their minds to this, but it genuinely baffles me that other people don't get it.

I've dealt with bird killing elsewhere, but Bryce contrasts the prosecution of Exxon for killing 85 birds in uncovered tanks with the fact that:

Michael Fry of the American Bird Conservancy estimates that between 75,000 and 275,000 birds per year were being killed by U.S. wind turbines. And yet, the Department of Justice won't press charges. `Somebody has given the wind industry a get-out-of-jail-free card' Fry told me.

Bryce goes on to show that wind power does not reduce carbon dioxide emissions. At all. Even in Denmark, with its unique ability to switch Norwegian hydro plants on and off when needed:

If Denmark's huge wind-power sector were reducing carbon dioxide emissions, you'd expect the Danes to be bragging about it, right? Well, guess what? They're not...The September 2009 study by CEPOS [a Copenhagen think thank] said that Denmark's wind industry `saves neither fossil fuel consumption nor carbon dioxide emissions'.

Then there's the need for long transmission lines to link up remote renewable power plants with customers. Recently wind farms in Oregon were forced to feather their blades because they were producing far too much power for the local grid during a sudden storm. The solution is better linkage between local grids, but that means more pylons. Wind alone will require 40,000 miles of new power lines - covering an area the size of Rhode Island.

Then there are the rare earths, or lanthanides. The wind industry relies almost entirely on neodymium-iron-boron magnets, importing all the neodymium from China.

Environmental activists in the United States and other countries may lust mightily for a high-tech, hybrid-electric no-carbon, super-hyphenated future. But the reality is that that vision depends mightily on lanthanides and lithium. That means mining. And China controls nearly all the world's existing mines that produce lanthanides.

Bryce's book is more than a demolition of renewable energy. It contains a fascinating and detailed account of the shale gas revolution and of the latest developments in modular nuclear technology. It makes a persuasive case that this century will be dominated by `N2N' energy - natural gas to nuclear - and that the consequence of the rise of both will be continuing steady decarbonisation of the economy. This is the best book on energy I have read. It confirms my optimism - and my rejection of the renewable myth.

The Wall Street Journal has a great article about how nostalgic people get for the way air travel used to be in the 1950s -- with more leg room, less hassle and more romance.

Piffle. Compard with today, it was expensive, dangerous and slow:

The piston-driven planes of those days, like the Lockheed Constellation and Douglas DC-7, were noisy and often ferociously bumpy. They couldn't fly over storms and turbulence the way jet-powered airplanes can. Engine failures were more frequent. So were crashes. And the cost of a ticket was affordable for only an elite few.

The 1960s were no picnic either:

In one month alone-January 1969-eight airliners were hijacked to Cuba... The fatal accident rate per departure in 1969 was 13 times higher than in 2009.

Here's the Journal's remarkable table comparing different eras in flight:

Includes this picture of the author looking pessmistic because about to be eaten by sabre-toothed cat, and because he has his head by the rear end of a monkey.

Today, the defining struggle in the world is between relentless growth and the potential for collaboration.

This is very odd in all sorts of ways.

First, the implication seems to be that `relentless' growth might be a bad thing. Tell that to those suffering as a result of the recession - the very opposite of growth - or those living in poverty who would - in some cases will - die for lack of relentless growth.

Second, in what sense is there a `struggle', let alone a defining one? Does he mean that those who espouse growth are fighting those who espouse collaboration (I suspect he means co-operation, a word with less sinister connotations)? I can't think which conflict this applies to.

But third, the most remarkable thing about this sentence is the implication that growth comes at the expense of collaboration. I find it astounding that anybody can really think this after Montesquieu and Condorcet, Adam Smith and David Ricardo, Friedrich Hayek and Paul Romer, after tit-for-tat and gains from trade, after South Korea and North Korea.

Wherever the ways of man are gentle, there is commerce,

said Montesquieu,

and wherever there is commerce there the ways of men are gentle.

Surely the way growth happens is by people exchanging and specialising, by people bringing together and combining their ideas into technologies and practices that supply each other's needs. The way to grow is to make or do something that somebody else needs or wants. In a word, by collaborating.

Let us charitably assume that the university head has signed a letter written by some fund-raising consultant (which is why I am not naming him). Said consultant no doubt thinks that the sentence expresses an unexceptional and obvious truth. After all he is likely to have heard that economic growth comes at the expense of collaboration from almost every parent, priest, paper and professor he encounters. It is indeed conventional wisdom.

Depressing to find it parroted by the head of a university, though.

A reporter went down in a minisubmarine and looked at a pristine coral reef. Newsnight interviewed lawyers, fishermen and politicians.

But there was no sign of a slick, a slimed pelican or even a tar ball in their reports.

Then I found this on ABC News and the penny began to drop.

For 86 days, oil spewed into the Gulf of Mexico from BP's damaged well, dumping some 200 million gallons of crude into sensitive ecosystems. BP and the federal government have amassed an army to clean the oil up, but there's one problem -- they're having trouble finding it.

The leak is capped and the spill appears to be shrinking, but where is it going?

At its peak last month, the oil slick was the size of Kansas, but it has been rapidly shrinking, now down to the size of New Hampshire.

Today, ABC News surveyed a marsh area and found none, and even on a flight out to the rig site Sunday with the Coast Guard, there was no oil to be seen.

"That oil is somewhere. It didn't just disappear," said Plaquemines Parish President Billy Nungesser.

Salvador Cepriano is one of the men searching for crude. Cepriano, a shrimper, has been laying out boom with his boat, but he's found that there's no oil to catch.

"I think it is underneath the water. It's in between the bottom and the top of the water," Cepriano said.

Even the federal government admits that locating the oil has become a problem.

"It is becoming a very elusive bunch of oil for us to find," said National Incident Cmdr. Thad Allen.

The numbers don't lie: two weeks ago, skimmers picked up about 25,000 barrels of oily water. Last Thursday, they gathered just 200 barrels.

Still, it doesn't mean that all the oil that gushed for weeks is gone. Thousands of small oil patches remain below the surface, but experts say an astonishing amount has disappeared, reabsorbed into the environment.

"[It's] mother nature doing her job," said Ed Overton, a professor of environmental studies at Louisiana State University.

Looks like photo-oxidation and biodegradation work well in warm water, just like some scientists argued.

Here's another report

Reporters flying over the area Sunday spotted only a few patches of sheen and an occasional streak of thicker oil, and radar images taken since then suggest that these few remaining patches are quickly breaking down in the warm surface waters of the gulf.

And another:

Since BP capped the renegade Macondo well at the center of the Gulf oil disaster 12 days ago, the oil slick has shrunk to about 10,000 square miles from 80,000 square miles in just a matter of weeks.The reduction has amazed scientists who are tracking the spill and raised many questions about where all the oil has gone.

Natural resilience.

Update

It looks like my guarded rational optimism on the oil spill was perhaps if anything too cautious. In Time magazine, Michael Grunwald exposes the hype even more starkly:

So far - while it's important to acknowledge that the long-term potential danger is simply unknowable for an underwater event that took place just three months ago - it does not seem to be inflicting severe environmental damage. "The impacts have been much, much less than everyone feared," says geochemist Jacqueline Michel, a federal contractor who is coordinating shoreline assessments in Louisiana.

...Anti-oil politicians, anti-Obama politicians and underfunded green groups all have obvious incentives to accentuate the negative in the Gulf. So did the media, because disasters drive ratings and sell magazines; those oil-soaked pelicans you keep seeing on TV (and the cover of TIME) were a lot more compelling than the healthy pelicans I saw roosting on some protective boom in Bay Jimmy. Even Limbaugh, when he wasn't downplaying the spill, was outrageously hyping it as "Obama's Katrina." But honest scientists don't do that, even when they work for Audubon.

"There are a lot of alarmists in the bird world," Kemp says. "People see oiled pelicans, and they go crazy. But this has been a disaster for people, not biota."

Of course, I did not invent this idea. In keeping with the theory, I merely put together the ideas of others, notably those of Joe Henrich (collective intelligence), Rob Boyd (cumulative culture), Paul Romer (combinatorial ideas), Haim Ofek (the invention of exchange) and many others.

There was also the important thought that came from Adam Powell, Stephen Shennan and Mark Thomas, namely that temporary `outbreaks' of new technology in Paleolithic Africa probably have a demographic explanation. That is, when population density rose, it resulted in a spurt of innovation; when population density fell, it resulted in technological regress (as happened in Tasmania when it was isolated). Technology was sophisticated, in other words, in proportion to the number of people networked by exchange to sustain and develop it.

By this interpretation, animals with plenty of culture but no habit of exchange and specialisation between groups -- killer whales, chimpanzees, crows, Neanderthals -- do not experience headlong technological and economic `progress', however clever they get.

Michelle Kline and Rob Boyd have since produced evidence from Pacific islands that technological complexity correlates with population size (and contact with other islands):

In Oceania, around the time of early European contact, islands with small populations had less complicated marine foraging technology. This finding suggests that explanations of existing cultural variation based on optimality models alone are incomplete because demography plays an important role in generating cumulative cultural adaptation. It also indicates that hominin populations with similar cognitive abilities may leave very different archaeological records, a conclusion that has important implications for our understanding of the origin of anatomically modern humans and their evolved psychology. 

Now comes a new thought from a completely different direction. A Russian and a Ukrainian scientist have been modelling the universe to  understand what happens when civilisations from different planets meet (hat tip Marc Merlin). Technology Review takes up the tale:

The parameters that govern the evolution of this universe are simple: the probability of a civilisation forming, the usual lifespan of such a civilisation and the extra bonus time civilisations get when they meet.

The result gives a new insight into the Fermi Paradox. Bezsudnov and Snarskii say that for certain values of these parameters, the universe undergoes a phase change from one in which civilisations tend not to meet and spread into one in which the entire universe tends to become civilised as different groups meet and spread.

Of course, it is only a model. That is to say, Bezsudnov and Snarskii assume the conditions that lead to their conclusion:

We assume, that the unique reason which can prolong a lifetime of the Civilization, is the contact to other Civilizations. The meeting of Civilizations generates the new purposes and objects of knowledge, necessity to use an Intellect.

They have not proved, for example, why civilisations must die after a certain time if they don't meet others. But the description of isolated interstellar civilisations eventually and explosively linking up and `globalising' is a pretty good description of what happened on planet earth over the past 100,000 years:

It is shown that there exists a scenario when at the given moment almost all Civilizations are lonely- ``there is nothing'', however after some, sufficiently prolong time Civilizations will get into a contact and the Universe as a whole becomes civilized. Conclusion is that it is necessary to wait!

That's an exciting thought with which to go off on holiday. Back in mid August.

Sounds like I am complaining? Read on.

From the patio of our house can be seen a constant procession of wonderful (and remarkably tame) birds, attracted by the effect of the the suburb's sprinklers in the usually dry landscape. Squirrels come to the trees; garter snakes to the wall; butterflies to the flowers. In the crystal stream at the bottom of the hill, wild rainbow trout rise to caddis flies and dippers, martins and sandpipers snack on huge stoneflies. In the woods along the valley are moose droppings and signs of the occasional black bear.

My point? Well, the book I have just finished reading here is "Nothing to Envy" by Barbara Demick, about the lives of six North Koreans in the city of Chongjin before they defected to the south. They lived free from the evils of consumerism, indeed in the late 1990s they were so free of consumerism that their children or parents starved to death before their eyes. They never faced the paralysing agony of choosing between bagel brands, indeed for a lot of the time they ate meals based on stewing grasses and the husks of corn cobs. They had few possessions at all, let alone SUVs. Their pets needed no grooming, because they had been eaten. And they lived as locavores off the land, in all its organic purity, recycling their waste so that the local farmland stank of 'night soil'. All around Chongjin by the 1990s the wildlife had been trapped, the wild plants picked, the grasses cut for food and even the bark of trees stripped to make flour.

How's this for local-sourcing?

They devised traps out of buckets and string to catch small animals in the field, draped nets over their balconies to snare sparrows. They educated themselves in the nutritive properties of plants. They reached back into their collective memory of famines past and recalled the survival tricks of their forefathers. They stripped the sweet inner bark of pine trees to grind into a fine powder that could be used in place of flour. They pounded acorns into a gelatinous paste that could be molded into cubes that practically melted in your mouth. North Koreans learned to swallow their pride and hold their noses. They picked kernels of undigested corn out of the excrement of farm animals...on the beaches, people dug out shellfish from the sand and filled buckets with seaweed.

Sounds like the ideal way of life as preached by much of the western environmental priesthood, does it not? Yet between 600,000 and 2 million died of hunger. The wildlife was devastated. Pollution was terrible.

When the subjects of Demick's book reach China they are amazed not just by the human prosperity --one finds a bowl of white rice, a luxury she has not seen for ages, and then realises it had been left out for a dog -- but by the biodiversity, too. They marvel at the lush forests:

On the other side of the river, there was a place where the trees still had bark and the cornfields weren't guarded by guns. The place was called China.

There is something terribly wrong with the standard litany we recite about the environment. It just is not true that extravagant western lifestyles come at the expense of nature. The more I see of the world, the more persuaded I am that human prosperity is actually good for wildlife, because it leads to investment in things that boost biodiversity. Things like productive farms and sewage treatment and well stocked stores and fossil fuels and lawn sprinklers and bird feeders and sport fishing lobbies and national parks. Things that make it unnecessary to use the local forest as a source of fuel, the local valley as a source of food and the local stream as a dump for waste. Things that value a moose as something other than a meal.

The oft repeated recommendation of the environmental movement that we live more locally, live off the land, live with fewer choices, fewer inputs, fewer resources and fewer possessions would in fact result in devastation not just for human life but for wildlife too. Going back to nature would be a disaster for nature.

One day, in the mountains of North Korea, birds will be abundant and tame again, streams will be clean again, deer will refill the woods - but only if the people get rich enough to get their food through trade from choice-crammed bagel stores rather than from the land.

There have been Ebola virus, Lassa fever, swine flu, bird flu, swine flu again, SARS, the human form of mad cow disease, and many more such scares. Every single one proved exaggerated -- greatly, vastly so.

To add insult to injury, when each scare fails to materialise, officials close ranks and congratulate themselves on averting it. The latest example is Britain's insulting official review of the swine flu fiasco, as described by Michael Fitzpatrick in Spiked:

The independent review of the UK response to the 2009 pandemic carried out by the former Welsh chief medical officer, Dame Deirdre Hine, concludes that 'overall the UK response was highly satisfactory': 'The planning for the pandemic was well developed, the personnel involved were fully prepared, the scientific advice provided was expert, communication was excellent, the NHS and public health services right across the UK and their suppliers responded splendidly and the public response was calm and collaborative.' Splendid!

Remember this was after spending an estimated £1.2 billion of your and my money on something that lost of us thought would prove a non-event from the start. Such complacency is infuriating.

The latest scare is an antibiotic resistant strain of bacterium called `New Delhi Metallo-beta-lactamase 1-positive'. It is said to be spreading among 'medical tourists' travelling to India for cosmetic surgery, and it presages the end of civilisation, according to Tim Walsh in Lancet Infectious Diseases last week:

In many ways, this is it. This is potentially the end. There are no antibiotics in the pipeline that have activity against NDM 1-producing Enterobacteriaceae.

Antibiotic resistant strains of bacteria have been a threat for decades and these apocalyptic cries of wolf are getting tiresome. Resistance is an evolutionary phenomenon. We expose billions of bacteria to intensely strong selection pressure in a tempting environment (hospitals, with a procession of patients with open wounds in shared rooms) and -- behold -- we select for strains that thrive on our antibiotics. So we invent new antibioitics and the arms race continues.

Cvilisation does not end, for three reasons. First, we keep inventing new antibiotics. Second, we get better at hygiene. Remember, it was antiseptic practice that first made hospitals safe place to be ill, not drugs. So even if the supply of new antibioitcs does dry up, as we have been told for decades it will, we need not be back to medieval levels of disease, just early 20th century levels. Third -- and here is a fact no journalist ever, ever remembers to pass on to readers -- antibiotic resistance goes away if you stop using the antibiotic.

When you take the selection pressure that selected for a trait away, the trait gradually vanishes -- especially if the trait is energetically expensive, as antibiotic resistance is for bacetria. For example, here's a report from the literature:

Precipitous declines first in the numbers of isolates with high-level resistance (from 31% to 4%) and then in those with low-level resistance (from 26% to 10%) accompanied prescription control.

and here's the title of a paper published last month:

The Decline of Pneumococcal Resistance after Cessation of Mass Antibiotic Distributions for Trachoma

If you stop using an antibiotics, resistance will gradually decline. Surely we can recruit evolution to our cause in our arms race. That is to say, we can accelerate the decline by ingeniously setting up the selection pressure so that resistant strains die out. I don't know how -- we need to somehow reward bacteria for being susceptible. Have a secure place in each hospital where we breed the darned things and let them out to compete with their resistant conspecifics? Sounds weird, I admit, but we need more health professionals to start understanding evolution so they can think their way to solutions.

If health officials learned just a little about evolution they might also be less panicky and financially profligate when confronted with flu scares. In normal times and normal societies, flu strains MUST evolve towards low virulence, because in victims who are still leading normal lives, they will encounter more new victims. That is true of all casual contact diseases (hence the mildness of all colds), though not of insect-borne, sexually transmitted or water-borne diseases -- which often thrive when their victims are immobilised and moribund. The peculiar conditions of first-world-war field hospitals, with nurses moving between the injured and huge fresh supplies of injured people, undoubtedly selected for an unusually virulent strain on flu. In a strain spreading in normal society, that will not happen.

Dear Sir,

John Gray, in his review of my book The Rational Optimist accuses me of being an apologist for social Darwinism. This vile accusation could not be farther from the truth. I have resolutely criticised both eugenics and social Darwinism in several of my books. I have consistently argued that both policies are morally wrong, politically authoritarian and practically foolish. In my new book I make a wholly different and more interesting argument, namely that if evolution occurs among ideas, then it is ideas, not people, that struggle, compete and die. That is to say, culture changes by the mutation and selective survival of tools and rules without people suffering, indeed while people themselves prosper. This is precisely the opposite of social Darwinism in the sense that it is an evolutionary process that enables the least fit people to thrive as much as the fittest.

Gray writes `There is nothing in society that resembles the natural selection of random genetic mutations; even if such a mechanism existed, there is nothing to say its workings would be benign. Bad ideas do not evolve into better ones.' I refer him to the wok of Robert Boyd, Peter Richerson, Joe Henrich and others on exactly this point, especially their fascinating paper  `Five misunderstandings about cultural evolution'. As for the notion that this cultural evolution is not benign, I prefer to live in a world where global child mortality has fallen by two-thirds in my own lifetime, a world where hunger and slavery are slowly disappearing, racial and sexual equality are generally improving, the goods and services that the average person can afford are increasing and many rivers and the air of many cities are rapidly getting cleaner. These things come about through the selective survival of technologies and ways of organizing them. Government plays a role, yes, but so do other human institutions.

Gray writes that `In Africa, the Indian subcontinent and the small Pacific nations, some of the world's poorest societies are already suffering from climate change. Telling them they need more economic growth is not very helpful when they are being destroyed by drought or rising sea levels.' This remark, worthy of Marie-Antoinette, could not be more wrong. The suffering caused by climate change is (and is predicted by the IPCC for decades to continue to be) minuscule compared with the suffering already being caused by preventable problems: malaria, malnutrition, indoor air pollution, dirty water. Solving those problems through the eradication of poverty (ie, economic growth) would not only save far more lives, it would also enable people to tolerate climate change better without suffering. The World Health Organisation estimated in 2002 that 150,000 people were dying each year as a result of climate change. Even if you ignore the suspect assumptions behind this number (it includes an arbitrary proportion of diarrhoea and malaria deaths, and in a later estimate even inter-clan warfare in Somalia), these deaths represent less than 0.2% of all deaths and are dwarfed by deaths caused by iron deficiency, cholesterol, unsafe sex, tobacco, traffic accidents and other things, not to mention 'ordinary' diarrhoea and malaria.

Finally, Gray hilariously writes that `Laissez-faire was…imposed on society through the use of state power.' Should a slave be grateful to be released or angry at having been enslaved in the first place?

Sincerely

Matt Ridley

by Matthew Ridley

Janice Turner provided an amusing dose of irrational pessimism in The Times on 21 August (behind a paywall) with an argument for population control. Talking of China's efforts to control population, she says that:

That one-child policy, you have to concede, certainly works

Her only evidence for such a startling proposition is that she went to Beijing and discovered that it didn't feel very crowded. I can't say for sure but I think the `hundreds and thousands of girls and disabled children abandoned each year' in China, or the millions of Chinese women who have suffered from forced abortions under the policy (well worth reading the full post), may not find such an argument very convincing. According to one writer,

China's one-child policy causes more violence to women and girls than any other official policy on earth.

Sadly the rest of the Times article does not improve much on this bad start. Janice Turner's arguments become increasing economically questionable. For example, there is this gem:

The one-child policy also aids the economy since, having to fork out less on child-raising, [Chinese parents] can afford more consumer goods, [such as] a car

This is an example of a classic economic fallacy recently debunked in an excellent article by the FT's John Kay. The resources spent on making a consumer good such as a car are economic costs rather than benefits; the "benefit" is the value the consumer gets from owning said car. If some parents would have derived more value from a second child than from a car, but are forced to buy a car thanks to the one-child policy, that is a loss to them and to the economy.

Then she says this:

In a world with ever greater strain on natural resources...is the number of children in a family only a private concern?

Well, yes, actually it is, because the child's parents pay (whether through prices or taxes) for all the resources used to care for their children. If we think the production of those resources imposes external costs on others, then we should increase their price, not ban babies. Equally, if such resources start to run out, then market forces will raise their prices, which in turn will encourage people to innovate around such resource shortages.

It is said that we need new workers to support an ageing population. But we expect our old to stay in work even longer, which, if we continue to breed at this rate, will mean more young unemployed.

This is a classic illustration of the depressingly common "lump of labour" fallacy, which assumes there is a fixed amount of work to be done in the economy which needs to be divided up among the population. No good economist believes this to be true: more work in the economy will stimulate economic growth and consumption, which in turn creates more jobs for others. Countries with higher populations do not have higher unemployment rates.

In fairness to Janice Turner, she does not advocate a one-child policy for the West. Instead she proposes more moderate 'solutions' such as financial incentives for having fewer children. But frankly she has failed to convince me that population needs to be controlled at all. A rational optimist would recognise that there are many benefits to a larger world population, such as more minds to think up new innovations and add to the store of collective intelligence. Sure, we should probably not subsidise new births, as the UK Child Benefit does, but we shouldn't restrict them either. Let's remember that world per-capita income increased massively over the past century even as population skyrocketed, and that population is set to level off in mid-century by itself anyway (see chart below from World Resources Institute)

The most violent official policy in the world towards women and girls is not what the West should be emulating now.

Why, then, did American liberalism, starting in the early 1970s, undergo a historic metanoia, dismissing the idea of progress just as progress was being won? Multiple political and economic forces paved liberalism's path away from its mid-century optimism and toward an aristocratic outlook reminiscent of the Tory Radicalism of nineteenth-century Britain; but one of the most powerful was the rise of the modern environmental movement and its recurrent hysterias.

I especially enjoyed his quotation from my late colleague Norman Macrae:

Touring American campuses in the mid-1970s, Norman Macrae of The Economist was shocked "to hear so many supposedly left-wing young Americans who still thought they were expressing an entirely new and progressive philosophy as they mouthed the same prejudices as Trollope's 19th century Tory squires: attacking any further expansion of industry and commerce as impossibly vulgar, because ecologically unfair to their pheasants and wild ducks."

It's time to reclaim the word `progressive'  for those who welcome change and are optimistic about human potential.

From today's Times, my op-ed piece.

This month, after a three-year investigation, Harvard University suspended a prominent professor of psychology for scandalously overinterpreting videos of monkey behaviour. The incident has sent shock waves through science because it suggests that a body of data is unreliable. The professor, Marc Hauser, is now a pariah in his own field and his papers have been withdrawn. But the implications for society are not great - no policy had been based on his research.

Yesterday, after a four-month review, a committee of scientists concluded that the Nobel prize-winning Intergovernmental Panel on Climate Change (IPCC) has "assigned high confidence to statements for which there is very little evidence", has failed to enforce its own guidelines, has been guilty of too little transparency, has ignored critical review comments and has had no policies on conflict of interest.

Enormous and expensive policy changes have been based on the flawed work of these scientists. Yet there is apparently to be no investigation, blame, suspension or withdrawal of papers, just a gentle bureaucratic fattening of the organisation with new full-time posts.

IPCC reports are supposed to be the gold standard account of what is - and is not - known about global warming. The panel boasts that it uses only peer-reviewed scientific literature. But its claims about mountain ice turned out to be anecdotes from a climbing magazine, its claims on the Amazon's vulnerability to drought from a Brazilian pressure group's website and 42 per cent of the references in one chapter proved to be to reports by Greenpeace, WWF and other "grey" literature. Yesterday's review finds that guidelines on the use of this grey literature "are vague and have not always been followed".

For instance, the notorious claim that glaciers in the Himalayas would disappear by 2035 seems to have been based on a misprint (for 2350) in a document issued by a pressure group. When several reviewers challenged the assertion in draft, they were ignored. When Indian scientists challenged it after publication, they were not just dismissed but vilified and accused of "voodoo science" by the IPCC chairman, Rajendra Pachauri.

By contrast, when two academics, Ross McKitrick and Pat Michaels, found a strong link between temperature rise and local economic development - implying that recent warming is partly down to local, not global factors - their paper was ignored for two drafts, despite many review comments drawing attention to the omission. It was finally given a grudging reference, with a false assertion that the data were rebutted by other data that turned out to be non-existent.

We now know the back story of this episode: the e-mails leaked from the University of East Anglia include this from Professor Phil Jones, referring to exactly this paper: "I can't see either of these papers being in the next IPCC report. Kevin and I will keep them out somehow - even if we have to redefine what the peer-review literature is!"

(Note that the IPCC had appointed Professor Jones as co-ordinating lead author to pass judgment on his own papers, as well as those of his critics. Learning nothing, it has appointed one of Professor Jones's closest colleagues for the next report. This is asking not to be taken seriously.)

These are not merely procedural issues. They have real consequences for science and society. All the errors and biases that have come to light in recent months swerve in the direction of exaggerating the likely impact of climate change. According to the economist Richard Tol, one part of the 2007 report (produced by Working Group 2) systematically overstated the negative impacts of climate change, while another section (written by Working Group 3) systematically understated the costs of emissions reduction.

Indur Goklany, an independent science scholar, likewise noticed that the report had quoted a study that estimated the number of people at increased risk of reduced water shortage in the future as a result of climate change, but omitted to mention the same source's estimate of the number of people at decreased risk. The latter number was larger in all cases, so that "by the 2080s the net global population at risk declines by up to 2.1 billion people".

This is not a new problem. The unilateral redrafting of IPCC reports by "lead authors" after reviewers had agreed them, and the writing of a sexed-up "summary for policy makers" before the report was complete, have discomfited many scientists since the first report. It is no great surprise that the "experts" who compiled one part of the 2007 report included three from Greenpeace, two Friends of the Earth representatives, two Climate Action Network representatives, and a person each from the activist organisations WWF, Environmental Defense Fund, and the David Suzuki Foundation.

Frankly, the whole process, not just the discredited Dr Pachauri (in shut-eyed denial at a press conference yesterday), needs purging or it will drag down the reputation of science with it. One of the most shocking things for those who champion science, as I do, has been the sight of the science Establishment reacting to each scandal in climate science with indifference or contempt. The contrast with the thorough investigation of the Hauser affair is striking.

Three years ago, not having paid much attention, I thought that IPCC reports were reliable, fair and transparent. No longer. Despite coming from a long line of coal-mining entrepreneurs, I'm not a "denier": I think carbon dioxide is a greenhouse gas. I'm not even a sceptic (yet): I think the climate has warmed and will warm further. But I am now a "lukewarmer" who has yet to see any evidence saying that the current warming is, or is likely to be, unprecedented, fast or tending to accelerate.

So I have concluded that global warming will most probably be a fairly minor problem - at least compared with others such as poverty and habitat loss - for nature as well as people. After watching the ecologically and economically destructive policies enacted in its name (biofuels, wind power), I think we run the risk of putting a tourniquet round our collective necks to stop a nosebleed.

I suppose one should not be surprised. Every movement, from Christianity to Bolshevism, had the same transformation. How the church went from being a radical insurgent organization that gave a voice to the poor to one that insisted on papal infallibility without a backward glance always struck me as entertaining.

Mead argues that the entire environmental movement was founded on not trusting experts:

An increasingly skeptical public started to notice that 'experts' weren't angels descending immaculately from heaven bearing infallible revelations from God.  They were fallible human beings with mortgages to pay and funds to raise. They disagreed with one another and they colluded with their friends and supporters like everyone else. They often produced research that agreed with the views of those who funded their work (tobacco companies, builders of nuclear power plants, NGOs and foundations).

Whereas now:

When it comes to climate change, the environmental movement has gotten itself on the wrong side of doubt. It has become the voice of the establishment, of the tenured, of the technocrats. It proposes big economic and social interventions and denies that unintended consequences and new information could vitiate the power of its recommendations.  It knows what is good for us, and its knowledge is backed up by the awesome power and majesty of the peer-review process. The political, cultural, business and scientific establishments stand firmly behind global warming today - just as they once stood firmly behind Robert Moses, urban renewal, and big dams.

They tell us it's a sin to question the consensus, the sign of bad moral character to doubt.

Bambi, look in the mirror.  You will see Godzilla looking back.

Back in the 1970s, I hugely enjoyed the novel The Monkey Wrench Gang by the eco-activist Edward Abbey. In that book, four unlikely comrades come together in a common cause - to blow up billboards, sabotage bulldozers and destroy dams to save nature. If you were to rewrite that book today (and I have to admit I am tempted) the comrades will be blowing up wind turbines, sabotaging biofuel plants and putting up placards at organic farms about their wasteful use of land.

In my book I argue that expertise, innovation and intelligence are bottom-up phenomena, dispersed through society and shared among many brains. The `cloud' is only the latest and strongest example of this. The top-down environmental establishment is on the wrong side of history.

Environmental scientists responded with a determination to stamp out this heresy that would have done Torquemada or Khomeini proud. A dozen scientists served Cambridge University Press with a demand that it cease printing the book, fire the editor who oversaw it,  and "convene a tribunal" to investigate the book's "errors." Nature ran a truly egregious review by the scientists Stuart Pimm and Jeffrey Harvey attributing to Lomborg ridiculous statements that he never even remotely made in the book or anywhere else. And Pimm and Harvey along with other members of the environmental goon squad lodged a complaint with the Danish Committee on Scientific Dishonesty - a legal body of the state - alleging that Lomborg had committed "scientific misconduct" for having reached conclusions that Pimm and Harvey did not like.

In 1979, Sony introduced the Walkman, the first portable music player. It weighed 14 ounces and cost $200. It could play a cassette that could hold about 90 minutes of music. It was a little bigger than a cassette. It was pretty ugly.

A new nano from Apple was announced yesterday. It weighs less than an ounce. The 8GB model is $149. It holds about 60 hours of music. It is smaller than a matchbook. It is very beautiful.

So it is cheaper (even without accounting for inflation), weighs 1/15th as much, and holds about 40 times more music of higher quality. I can't get over how beautiful it is.

What strikes me about this kind of story is how invisible it is. Even among thos of us old enough to remember the Walkman's launch, not enough people know the facts about how much more we can get for how much less. I might start collecting them (the stories).

Twice, while being interviewed about my book I have been told by the interviewer that it is a bad thing that I can buy green beans from Africa `because the food should be kept in Africa to feed people there'. The sheer ignorance of this statement, let alone its patronising tone, left me open-mouthed on both occasions. Think how many calories of wheat an African bean exporter can afford to buy for the price he receives for the few calories in his beans. He is growing the most valuable crop he can so that he can afford to import things of greater value to him than surplus beans.

Distant food is efficient, sustainable, safe and moral.

Pile's starting point is a new paper that grapples wih the paradox. It puts forward four explanations

(1) We have measured well-being incorrectly; 

(2) well-being is dependent on food services, which are increasing, and not on other services that are declining; 

(3) technology has decoupled well-being from nature; 

(4) time lags may lead to future declines in well-being.

You can just hear their hearts lifting that that last prospect. Phew. Armageddon is delayed. Just you wait!

But of course the whole paradox is misconceived. Human beings do not just live off ecosystems. They garden and nurture them so that they are more productive -- and sometimes so boost their productivity that they support still more wildlife as well.

As Helmut Haberl has calculated, some ecosystems are now so much higher in primary productivity than their original wild equivalents -- principally because of fertilisers and irrigation -- that they can divert half their energy into human consumption and still support more wildlife as well. Other ecosystems, on the other hand, are less productive than before people began to interfere with them, and are having to support lots of people, so leaving much less for wildlife. The challenge is to make more of the latter like the former, capable of supporting lots of people and lots of wildlife.

It's not just food. There is energy, where a nuclear power plant places less strain on nature than ten thousand wood cutters gathering fuel for charcoal burners. And then there is shelter, where the use of steel and concrete and plastic, all from underground, takes away the need for wood from forests. And so on.

I would even argue that human beings sometimes encourage ecological diversity too. The flowers and birds of farmland where I live -- cornflowers and peewits and partidges, for example -- must have been very few and far between when this was just a monotonous oak forest. Likewise, the cliff-nesting birds that abound now -- house martins and sparrows and rock doves -- must have been scarce before towns. We create lots of different habitats -- urban, rural, agricultural, forested, scrubby and so on -- where before there was uniformity. Of course, in the process, we upset balances, drive species locally extinct and so on. But half the time we are taking away what we created. The corncrake no longer thrives where I live, but nor did it 5,000 years ago when it was all oak forest.

The environmentalist's paradox has it backwards. The most sustainable societies on the planet are the ones that don't rely on charcoal for fuel, or wild game for food. The richer we get the more chance we have of saving biodiversity.

``If you write a book saying the world is getting better, you might get away with being thought eccentric. But if you write a book saying that the world is going to go on getting better and that in 2100 people will be healthier, wealthier and wiser -- and have more rainforests too - you will be though stark, raving bonkers. It is just not sane to believe in a happy future for people and their planet.

Yet I cannot stop myself. I've looked at all the statistics, facts, anecdotes, predictions and pronouncements I can get hold of and they all seem to me to suggest that we will be better off in 2100 than we are now. Much better off.

Global warming, I hear you say. Yes indeed. The official forecasts say world temperature will rise by 2-4C in this century. It is going to have to start accelerating soon, because the rate of increase since 1980 is about 1C per century - and that's if you ignore the satellites and rely mainly on the land-surface records, which many now think are hopelessly contaminated with the effects of urbanisation. Even then, it has been slowing down.

Moreover, the very same official forecasts also say that global per-capita income will multiply by 4-16 times in the same period - and the higher the temperature, the higher the income. Seriously: go look at the numbers; that's what they say. The warmer we get, the richer we will get (or rather, the other way round). In which case, what exactly is the problem?

What about the ice-caps then? They will be gone, along with Bangladesh and Florida, surely. No. There's a satellite called GRACE, which is so clever it can weigh Greenland every time it goes over it. The scientists who tell it what to do have calculated that Greenland is losing 200 cubic kilometres of ice a year, and they say that scares them. Other scientists say no, Greenland is shrinking at half that rate, because the others forgot to correct for the rise and fall of the land beneath the ice.

Whatever. How much of Greenland's ice is 200 cubic kilometres? About one half of one hundredth of one percent - which means that Greenland is losing ice at the rate of half a percent per century. It will be half gone in 10,000 years. Or 20,000 if the other lot is right. So in 2100, Greenland's ice cap will be 99.5% intact - according to the scariest estimate.

Population, you reply. Well, did you know that population is growing at the rate of a little over 1% a year, whereas in the 1960s, it was growing at 2% per year. The number of net new people born each year has been falling for 20 years. World population quadrupled in the twentieth century. It won't even double in the twenty-first. The median UN projection has it levelling off in 2075 at roughly 1.5 times today's level.

Despite that quadrupling, we ended the twentieth century having largely extinguished famine (except in countries run by criminals, like North Korea and Sudan). We actually increased food production per capita by about 30% in 50 years -and we did so without ploughing new land. The world cereal harvest trebled from the same acreage. Repeat that trick - plausible with new seeds and technologies coming along all the time -- and we will feed  9 billion people in 2100 very comfortably from a smaller acreage than we plough today. We can rebuild large chunks of rainforest and other wilderness. We might even bring back some extinct species by genetic engineering.

Yes, you say, but the oil will run out. Actually people have been predicting the imminent exhaustion of fossil fuels since 1860. There are many decades' worth of coal and oil left at the right price, and as for gas: the biggest technology breakthrough of the last decade is the new ability to get gas out of shale, which means that suddenly America and China and Poland and other places are looking at abundant gas for at least a century. With nuclear getting cheaper and safer all the time and solar promising to help by mid century, I suspect fossil fuels will be obsolete before they are extinct.

Africa, you say. So great is its burden of poverty, violence and disease that it can never catch up. They said exactly the same about Asia in the 1960s.

The truth is that all my life I have been told that the future is bleak. Population, famine, cancer, viruses, climate change, desertification, falling sperm counts, acid rain - I've lost count of the reasons they give. Yet all my life, the health and wealth of people keeps on getting better. People live 30% longer than they did when I was born, on average all around the world. Child mortality is down by two-thirds, globally. People earn three times as much money as they did in the 1950s, corrected for inflation.

The world is also cleverer (IQ scores have risen), more equal (the `Gini coefficient' has fallen), nicer (charitable giving is up, violence is down), freer (autocrats have fallen), and even happier (yes, the statistics do show that happiness increases - a bit - when people get richer. The Thames is cleaner. Deaths from weather-related diseases are at record lows (yes - despite Pakistan). The quantity of oil spilled in the ocean has fallen by 90% since the 1970s (yes - despite BP).

Horrible things will still happen, but inch by inch, people will raise their living standards in this century. There is a lot to look forward to. Don't let anybody tell your children otherwise''

Among the take-home messages:

- that innovation is accelerating thanks to the ability to compare and combine. Dance is a great example.

- and that video is the future of the net now that bandwidth constraints are fading. The print-dominated era is looking like a brief aberration, just a few hundred years...

George Monbiot is in trouble. He has already had to make an apology for his mistakes in an attack on Richard North.

He's swinging like a weathervane on issues like vegetarianism and feed-in tariffs.

He has a strangely thin skin for somebody who viciously attacks others, describing a mild riposte by Jonathan Porritt as `amazingly unpleasant'.

And now he has now been caught out either deleting, or allowing The Guardian to delete, inconvenient comments that contradict or embarrass him. Here is what Julian Williams and Shub Niggurath say at Bishop Hill:

Monbiot asked visitors to his Guardian thread to come up with evidence of Dr Pachauri's unreliable bookkeeping.  He must have thought this impossible. The one account unable to be veiled from public scrutinywas Pachauri's TERI-Europe's and that had 85% of income missing from the books until prodded. I provided Monbiot with what he asked for.

Monbiot declared Pachauri's personal accounts and financial practices were shown by KPMG as being clean. In the light of the above however, Monbiot's unquestioning confidence in such conclusions were puzzling.

About midday the inconvenient evidence that I provided at the Guardian forum, along with discussions of that evidence with aghast Monbiot fans were removed from the thread. The thread was closed down.

Every single comment about the accounts was removed.

...It is one thing to put forward one's own points of view and cite half-truths as evidence; it is quite another to tamper with and remove facts from the public record to support an argument that does not stand up.

I am not altogether surprised at Monbiot's collapsing credibility. His `amazingly unpleasant' attacks on my book included such ludicrous distortions and mistakes that he's long ago lost my respect.

There is no full-blown logical paradox here. If a claim is ambitious, people should indeed tread warily around it, even if it comes from scientists; it does not follow that they should be sceptical of the scientific method itself. But there is an awkward public-relations challenge for any champion of hard-nosed science. When scientists confront the deniers of evolution, or the devotees of homeopathic medicine, or people who believe that childhood vaccinations cause autism-all of whom are as demonstrably mistaken as anyone can be-they understandably fight shy of revealing just how riddled with error and misleading information the everyday business of science actually is. When you paint yourself as a defender of the truth, it helps to keep quiet about how often you are wrong.

Very true. On scientific questions where I am orthodox (eg, alternative medicine, evolution), I notice that the heretics use precisely the same sorts of arguments as I do in those fields where I am a sceptic (eg, climate projections, crop circles). There seems to be no easy answer to the problem: when should you go for a heresy.

When materials are worth recycling, markets for their reuse naturally arise.  For materials with no natural markets for their reuse, the benefits of recycling are less than its costs - and, therefore, government efforts to promote such recycling waste resources.

Everyday experience should teach us this fact.  The benefits of recycling clothing, for example, are large enough to prompt us to buy costly clothes-recycling machines that we routinely use to recycle for tomorrow the clothes we wear today.  We call these machines "washers and dryers."  And when American families no longer want their clothing, organizations such as Goodwill come by to gather the discarded garments to recycle them for use by poor people.

People also recycle their homes.  The one I own and live in was previously owned by a family who recycled it - which included refurbishing it - rather than simply discarded it when they moved to another town.  Many people also drive recycled ("used") cars, stock their homes with recycled ("antique") furniture, listen to recycled ("used") CDs, and read recycled ("used") books.

Markets promote conservation when it's worthwhile; government promotes it when it's wasteful.

I'd never really thought about recycling in that way.

There is, of course, another reason to recycle even if it is costly and wasteful -- to prevent litter. But I have a feeling it achieves this rather poorly. Indeed, when it is costly or inconvenient and disposal is not made available as an option, people just break the rules and dump litter instead, so recycling can make litter worse.

Recently, the psychologist David Buss's team at the University of Texas at Austin reported that men, when looking for one-night stands, check out women's bodies. Or as they put it, "men, but not women, have a condition-dependent adaptive proclivity to prioritize facial cues in long-term mating contexts, but shift their priorities toward bodily cues in short-term mating contexts."

Like many results in evolutionary psychology, this may seem blindingly obvious, but that does not stop it from being controversial. Earlier this month a neuroscientist in Britain, Gina Rippon, lambasted what she called the "neurohype" about sex differences: "There may be some very small differences between the genders, but the similarities are far, far greater."

She has a point. Compared with, say, chimpanzees, men and women are not very different. Most of the interesting things about people-language, laughter, love, laptops-come just as naturally to both sexes.

Yet we would be a very peculiar animal species if we did not have sex differences in behavior as well as anatomy. In virtually every mammal and nearly all birds, males are more aggressive, females more nurturing. It is a distinction that goes right back to active sperm competing for stationary eggs in the primeval ocean. It was only reinforced when the invention of the placenta and the mammary gland gave male mammals a gigantic prize to compete for: nine months and several years of somebody else's bodily efforts. Wombs are worth fighting over-and granting to favored applicants only.

So it's no zoological accident that in all societies, however peaceful or violent, men are about 50 times more likely to kill other men than women are to kill women, and they do so most in young adulthood, when most actively competing for mates. Likewise, it is no neurophysiological accident that women coo over newborn babies more enthusiastically than men do. Women who showed interest in babies left more genes behind than those who were indifferent; men who turned violent left more genes.

These are the kinds of sex differences that we share with all other mammals. What intrigues me, though, is the possibility that human beings have other sex differences peculiar to themselves and derived from uniquely human habits of more recent origin.

Take the cliché of the golf-playing husband and the shoe-shopping wife. Not even an evolutionary psychologist would claim to find monkey equivalents to this. Yet the obsession with the trajectory of ballistic objects is as baffling to most women as the obsession with searching and re-searching every store for the perfect shoe bargain is to men. (I know there are exceptions, but admit it: Marriage surprises most people by revealing the truth of such clichés.)

In all hunter-gatherer societies there is a sharp difference between the foraging strategies of the two sexes. Men generally travel far in search of mobile prey that they need to bring down with well-aimed projectiles. Women generally go out in groups and search for good sources of roots, ripe berries or nuts, which they use their acute powers of observation to spot and collect.

Without knowing it, golf-course designers are setting up a sort of idealized abstraction of the hunting ground, while shoe retailers are setting up a sort of ersatz echo of the gathering field.

This sexual division of labor over foraging is not only far more marked in people than in most other animals (it was, arguably, the first "gain from trade" we stumbled upon, benefitting both sides), but it may be a relatively recent feature of our evolutionary history, invented in Africa just 150,000 to 300,000 years ago. Some archaeologists have concluded that Neanderthals did not practice it: that female Neanderthals were co-operative hunters with men, not gatherers.

That still gave the sexual division of labor plenty of time to leave its instinctive marks on the human psyche through genetic changes, raising the intriguing thought that some of our sex differences might be caused by our culture, yet also ingrained in our genes.

But something struck me as odd as I listened to the radio this morning. There was a lot of talk of `extinctions' of thousands of plants, as turned up by a new report from Kew Gardens. When I opened the newspapers (online), I found that actually the report was not about extinctions, but about threats of extinction. Then I looked at the list cited by the Times and Guardian. Right there at the top:

Wollemi pine (Wollemia nobilis) - critically endangered

The wollemi pine was discovered in 1994 in Wollemi National Park, Australia, and there fewer than 50 mature individuals are known. Its long-term regeneration from seed is unknown but seems doubtful due to competition with other trees. Its small size and limited range means it is at risk from any chance event such as fire or the spread of disease.

Er, sorry. How can a species that you can buy in a garden centre or online for £61.25 possibly be described as in danger of extinction? I have one in my garden. It is thriving.

Whoever decied to include that species on the list just damaged my trust in the rest of the list.

Second on the list at the Guardian:

Common snowdrop (Galanthus nivalis) - near threatened

The common snowdrop was once widely distributed in the east Carpathian mountains in central and eastern Europe. Although it is widely naturalised, including in the UK, during the past decade its native distribution has been considerably reduced, due mainly to habitat loss through the increase in residential developments and recreational land use.

My faith in the list just dropped another notch. I thought this was a list of species in danger of extinction, not in danger of dying out in its native range but thriving as never before elsewhere.

Let's try No 3.

Rosewood (Dalbergia andapensis) - critically endangered

D. andapensis is a species of rosewood, a highly valued timber used in the production of fine furniture and musical instruments. It is estimated that 52,000 tonnes of rosewood and ebony were logged in north-east Madagascar in 2009, and this habitat is itself under threat from conversion to agriculture for a growing rural population.

Hmm. Maybe. But highly valued and critically endangered do not usually go together. Cattle are highly valued. Sounds like a candidate for commercial farming: jobs exporting the raw materials for violins probably pay better than subsistence peasantry.

I am not in favour of extinction. But I do like the truth, rather than the spin.

As one of Crick's biographers I have done some interviews, for example with the LA Times.

My main reaction is that this is a thrilling discovery that adds lots of colour and enriches the story but does not rewrite history in any fundamental way. Not that I have read all the letters yet.

The star of the show is Maurice Wilkins, who always had a knack for expressing himself in a spicey and perceptive way. Consider this letter, written just after the debacle of December 1951 when Crick and Watson were being warned off DNA after building a botched model based on other people's data, misremembered:

Dear Francis, This is just to say how bloody browned off I am entirely and how rotten I feel about it all and how entirely friendly I am (though it may horrible appear differently). We are really between forces which may grind all of us into little pieces……I had to restrain Randall from writing to Bragg complaining about your behaviour. Needless to say I did restrain him, but so far as your security with Bragg is concerned it is probably much more important to pipe down and build up the idea of a quiet steady worker who never creates 'situations' than to collect all the credit for your excellent ideas at the expense of good will....And you see it does make me a bit confused about our discussions if you get too interested in everything which is important; where I say confused I mean confused, I am now largely incapable of any logical thinking in relation to polynucleotide chains or anything. And poor Jim - may I shed a crocodile [INSERT: & very confused] tear?

Jim (Watson), by the way, emerges with great credit. His account of then whole affair, in The Double Helix, shocked the world -- and especially Crick and Wilkins -- with its warts-and-all depiction of scientists as flawed, ambitious and not always nice human beings. Watson was accused of sexism towards Rosalind Franklin. These letters confirm every nuance of Watson's realism. They also remind us that it was especially Wilkins who could not get on with Franklin. For example (Wilkins again):

There is also a silly muddle over Franklin's talk here. I got a big notice saying it was internal only - just a discussion between colleagues who worked in the same lab. Then a lot of notices went round about the Colloquium and I took it for granted all had had the other note. Hence [Pauline] Cowan's remark to you. I think that as the intention was to have it a private fight it would be best to keep it entirely so, as I told Jim. It should be either public or private. Let's have some talks afterwards when the air is a little clearer. I hope the smoke of witchcraft will soon be getting out of our eyes.P.s. Tell Jim the answer to his question 'When did you last speak to her' is this morning. The entire conversation consisted of one word from me.

There's also a fascinating glimpse of how terrified Crick was, even after building the model of the double helix with Watson, that Linus Pauling would ride in a pinch the whole thing. Wilkins to Crick, March 1953:

If Rosie wants to see Pauling, what the hell can we do about it? If we suggested it would be nicer if she didn't that would only encourage her to do so. Why is every body so terribly interested in seeing Pauling? ...Now Raymond [Gosling] wants to see Pauling too! To hell with it all.

Gann and Witkowski have made a fantastic discovery. It's almost like finding a trove of letters from Newton, Darwin or Einstein.

This video was made by an organisation funded partly by the UK taxpayer.

An odd thing about people, compared with other animals, is that the more of us there are, the more we thrive. World population has doubled in my lifetime, but the world's income has octupled. The richest places on Earth are among the most densely populated.

By contrast, it's a fair bet that if you took a few million rabbits and let them loose on Manhattan island, they would starve, fight, sicken and generally peter out. Whether you like it or not, whether you think it can continue forever or not, you cannot deny that when people come together in dense swarms, they often get richer.

In this fact lies a vital clue to the nature of the human animal, one that has until recently been overlooked: namely, that what explains the sudden success of the human species over the past 200,000 years is not some breakthrough in individual ability, but rather the cumulative effects of collective enterprise, achieved through trade. A new study of fishing tackle in the South Pacific provides intriguing support for this notion.

Two anthropologists, Michelle Kline and Rob Boyd, collected information on the "marine foraging technology" used by native people in 10 different groups of Pacific islands at the time of Western contact. They assigned scores not only for the number of tools but also for their complexity. A stick for prying clams from the reef, for example, counted as one techno-unit, whereas a bamboo crab trap with a baited lever counted as 16, because it comprised 16 working parts, each a technology in its own right.

What they found was that the bigger the population, the more varied and more complex the tool kit was. Hawaii, with 275,000 people at the time of Western contact, had seven times the number and twice the complexity of fishing tools as tiny Malekula, with 1,100 people.

But it's not just the size of the population on the island group that matters, but the size of the population it was in contact with. Some small populations with lots of long-distance trading contacts had disproportionately sophisticated tool kits, whereas some large but isolated populations had simple tool kits. The well-connected Micronesian island group of Yap had 43 tools, with a mean of five techno-units per tool, while the remote Santa Cruz group in the Solomon Islands, despite having almost as large a population, had just 24 tools and four techno-units.

Mr. Boyd and his colleague Joe Henrich think that cultural change happens when one person learns a specialized skill and teaches it to others. But if others are poor learners or the teacher dies young, there is a tendency for skills to fade, creating a "treadmill of cultural loss," especially in small and isolated societies. Tasmania, for example, suffered a progressive simplification of its technology after its people were isolated by rising sea levels 10,000 years ago.

This tendency is counteracted by the sporadic innovation of expert specialists. Their ideas, embodied in technology, spread by trade and imitation. The greater the population and the connectedness between populations, the greater the pool of innovators to draw upon.

Archeologists suggest that the ephemeral appearances of fancy tool kits in parts of southern Africa as far back as 80,000 years ago does not indicate sudden outbreaks of intelligence, forethought, language, imagination or anything else within the skull, but simply has a demographic cause: more people, more skills.

Technology is more than just a barometer of human collaboration. It is the embodiment of human collective intelligence. Most of the technologies we use, as the economist Friedrich Hayek first observed, are things that nobody knows how to make from scratch. Humans have transcended the limits of their own brain power by combining their brains into networks.

Thanks to the Internet, the islands of humanity are now connected as never before, with only a few remote atolls like North Korea and Burma still holding out. So we can draw upon the inventiveness of a network of more than six billion people.

The history of in vitro fertilization demonstrates not only how easily the public will accept new technology once it's demonstrated to be safe, but also that the nightmares predicted during its development almost never come true. This is a lesson to keep in mind as we debate whether to pursue other promising yet controversial medical advances, from genetic engineering to human cloning.

The Nobel prize for Robert Edwards is long overdue. It should not be forgotten what a gauntlet he and Patrick Steptoe had to run when they pioneered IVF. Here's a taste, from an article in The Times in 2003:

In the mid-Eighties Edwards sued several papers, including The Times, for reporting comments by the British Medical Association suggesting, wrongly, that doctors should not work with him because he was involved in cloning. He did not particularly want to fight but "I just thought, what would happen if I don't issue libel actions? I'll be killed for ever". He had his day in court and, subsequently, grovelling apologies: "Many people think that scientists working on human beings are a bit soft, that it's soft science. I'd like to see them in court fighting a libel action. It's tough."

It's the flip side of the precautionary principle. How much harm are you failing to prevent if you do not press ahead with innovation? That is just as surely on your conscience as the risks you are running. Henig again:

As Dr. Edwards himself noted in the early 1970s, just because a technology can be abused doesn't mean it will be. Electricity is a good thing, he said, regardless of its leading to the invention of the electric chair.

Science fiction is filled with dystopian stories in which the public blindly accepts destructive technologies. But in vitro fertilization offers a more optimistic model. As we continue to develop new ways of improving upon nature, the slope may be slippery, but that's no reason to avoid taking the first step.

Now comes evidence of a different kind of collateral contamination by GM crops. Turns out GM maize contaminates neighbouring farms with extra profits. The fact that farmers are growing insect-resistant GM crops raises yields for those who are growing conventional maize, because it reduces the number of pests that are about.

By comparing actual insect damage against estimates of what damage would have occurred - derived from historical data and other measures of borer abundance - the researchers calculated that over the 14 years of their study, use of Bt varieties improved farmers' profits by about $3.2bn in Illinois, Minnesota and Wisconsin.

But most of this benefit - $2.4bn - was accrued in non-Bt fields.

This `area-wide suppression' effect is presumably true of chemical pesticides, too. An organic farmer with weedy, pest-infested fields is contaminating his neighbours' fields with weeds and pests, or to put it another way his neighbours are contaminating him with crop protection. Who's the free rider?

But the brilliant thing about Bt crops, of course, is that because the toxin is made inside the plant, you can only encounter it if you eat the plant, so the general insect fauna is unaffected. It can therefore thrive, unsprayed.

Higher profits for farmers means lower costs for consumers (think about it: competition can drive prices lower and effectively pass on the extra profits as savings). So GM crops are leading to higher yields which means ploughing less land, cheaper food and more insect life, which means more bird life.

Will somebody please remind me why my government still cravenly accepts a total ban on the growing of these crops in my country at the behest of so-called `green' groups? It is a disgrace.

I now walk out of restaurants if they say they do not serve GM food and I tell them why.

Is it because common ailments are caused by many different rare genetic variants?

I champion the theory that coal was crucial, because it showed increasing rather than diminshing returns (the more people mined, the cheaper it got) and it amplified productivity and commerce. But there is more to the story than that.

Here's her reply to me

...We agree at least that innovation is the key. That's a very, very important agreement. Joel Mokyr, Jack Goldstone, and our own Greg Clark join Matt Ridley, Robert Allen, and me in affirming it. It sets us Innovators off from most economists and historians, who are Accumulators. We say that the modern world got rich by (at a minimum) 1500% percent compared with 1800 not, as the sadly mistaken Accumulators say, because of capital accumulation, or exploitation of the third world, or the expansion of foreign trade. The world got rich by inventing cheap steel, electric lights, marine insurance, reinforced concrete, coffee shops, saw mills, newspapers, automatic looms, cheap paper, modern universities, the transistor, cheap porcelain, corporations, rolling mills, liberation for women, railways.

And here's my reply to her reply.

...Deirdre is delightfully right about many things, including the fact that the Accumulators are wrong. I should have taken more time to acknowledge what a struggle still lies ahead to persuade most of the academic world, let alone the rest of humanity, that the great economic expansion of the past 200 years did not come by piling up "resources" that were stolen from others, or from Gaia. The non-zero-sum message has not yet got through. So yes, compared with that, our little differences are trivial. Her use of innovation as a synonym for growth is a masterstroke.

And here is Greg Clark's latest contribution:

...Deirdre McCloskey points to the association in eighteenth century England between two innovations: the rise of bourgeois virtue, and the Industrial Revolution. But modern experience in China suggests this is an accidental conjunction. Economic growth may demand many social qualities, but virtue does not seem to be one of them.

And Deirdre's reply:

...But we all agree-Ridley, Clark, Mokyr, and I-that the cat of liberty is hard or impossible to put back in the hierarchical bag once the accidental liberals around the North Sea let it out, and especially once it resulted in the 2000% percent or more increase in human scope. For which praise God.

The first, by Brendan O'Neill, in Spiked (hat tip: Frank Stott), reveals the degree to which the miners helped themselves to cope by defying the psychological experts 700 metres above them.

The inconvenient truth is that the 33 miners survived underground not as a result of psychological advice and intervention but by sometimes rebellingagainst the psychologists who kept a watchful eye on their every move. The real story of the Chilean miners, for anyone who cares to look, is that the interventions of the various wings of the trauma industry often make things worse rather than better, and people are mostly happier and healthier without them. 

When they rebelled against having hour-long sessions with therapists, the therapists punished them by witholding treats!

The way the men were treated was like a microcosm of today's therapy industry. The censoring of letters spoke to the idea that people are psychologically fragile and easily harmed by other people's words. The deprivation of certain 'prizes' if they didn't speak to the mental-health team revealed the authoritarian dynamic behind today's therapeutic interventions. The notion that they wouldn't survive without external expertise highlighted the general view of all of us as needing guidance from the new gods of emotional correctness.

The second article, by Daniel Henninger in the Wall Street Journal, reminds us forcibly that it was market-driven innovation that saved the miners' lives. Take the center Rock drill bit, for example:

This is the miracle bit that drilled down to the trapped miners. Center Rock Inc. is a private company in Berlin, Pa. It has 74 employees. The drill's rig came from Schramm Inc. in West Chester, Pa. Seeing the disaster, Center Rock's president, Brandon Fisher, called the Chileans to offer his drill. Chile accepted. The miners are alive.

It was not a government that invented this technology, nor was life-saving the motive for inventing it.

The Center Rock drill, heretofore not featured on websites like Engadget or Gizmodo, is in fact a piece of tough technology developed by a small company in it for the money, for profit. That's why they innovated down-the-hole hammer drilling. If they make money, they can do more innovation.

Undirected innovation raises living standards all over the world. And it raised the miners, too.

The secret of human progress is and always has been to keep ideas moving, both so that they meet and mate with new ideas and so that they escape suppression at home. As the philosopher David Hume was the first to observe, China suffers from a geographic disadvantage in this respect: It is too easy to unify. When disunited it grows rich and innovative. But time and again emperors, from the Ming to the Maoist, have been able to establish tyrannical centralized rule and shut down trade, diversity and experiment.

Europe, with its centrifugal rivers, its peninsulas and mountain ranges, is very hard to unify by conquest. Ask Constantine, Charles V, Napoleon and Hitler. So European states could harbor commercial, intellectual and religious refugees from each other, keeping flames alive. The history of technology is littered with examples of Europeans who fled from one jurisdiction to another to a find a more congenial or generous ruler: Columbus, Gutenberg, Voltaire, Einstein.

Today, Chinese censorship notwithstanding, ideas can flit across borders quicker than thought. We can do with a few mouse clicks what Fibonacci had to take a leaky galleon across the sea to achieve.

Psychologists have shown that we systematically overestimate how much we understand about the causes and mechanisms of things we half understand. The Swedish health economist Hans Rosling once gave students a list of five pairs of countries and asked which nation in each pair had the higher infant-mortality rate. The students got 1.8 right out of 5. Mr. Rosling noted that if he gave the test to chimpanzees they would get 2.5 right. So his students' problem was not ignorance, but that they knew with confidence things that were false.

The issue of action bias is better known in England as the "dangerous dogs act," after a previous government, confronted with a couple of cases in which dogs injured or killed people, felt the need to bring in a major piece of clumsy and bureaucratic legislation that worked poorly. Undoubtedly the rash of legislation following the current financial crisis will include some equivalents of dangerous dogs acts. It takes unusual courage for a regulator to stand up and say "something must not be done," lest "something" makes the problem worse.

Motivated reasoning means that we tend to believe what it is convenient for us to believe. If you run an organization called, say, the Asteroid Retargeting Group for Humanity (ARGH) and you are worried about potential cuts to your budget, we should not be surprised to find you overreacting to every space rock that passes by. Regulators rarely argue for deregulation.

The focusing illusion partly stems from the fact that people tend to see the benefits of a policy but not the hidden costs. As French theorist Frédéric Bastiat argued, it's a fallacy to think that breaking a window creates work, because while the glazier's gain of work is visible, the tailor's loss of work caused by the window-owner's loss of money-and consequent decision to delay purchase of a coat-is not. Recent history is full of government interventions with this characteristic.

"Affect heuristic'" is a fancy name for a pretty obvious concept, namely that we discount the drawbacks of things we are emotionally in favor of. For example, the Deepwater Horizon oil spill certainly killed about 1,300 birds, maybe a few more. Wind turbines in America kill between 75,000 and 275,000 birds every year, generally of rarer species, such as eagles. Yet wind companies receive neither the enforcement, nor the opprobrium, that oil companies do.

Rare-earth minerals are the 15 elements in that funny box at the bottom of the periodic table -- known as lanthanides -- plus two others. About 95 percent of global production takes place in China, largely at one huge mining complex in Inner Mongolia. The lanthanides are essential to much of modern electronics and high-tech equipment of various kinds. The magnets in windmills and iPod headphones rely on neodymium. Lutetium crystals make MRI machines work; terbium goes into compact fluorescent bulbs; scandium is essential for halogen lights; lanthanum powers the batteries for the Toyota Prius. For some of these products, alternative materials are available (moving to a non-rare-earth technology would make those cute little white earbuds about the size of a Coke can, though). For others, there simply isn't a viable substitute.

In other words, those vast wind turbines depend on surface mining just as much as the fossil fuel industry does.

Two important facts about rare earths help explain why: They're not earths, and they're not rare. China has reached its dominant supplier position through good old-fashioned industrial aggression, not innate geographical superiority. Cheap labor, little environmental scrutiny, and a willingness to sell at low cost have made other producers give up. For competitors, like the owners of Mountain Pass, a California mine that shut down in 2002 partly due to the China factor, that has been a daunting combination. For the rest of us, it has been fantastic: Affordable rare earths have helped power the information-technology revolution, driving down the cost of everything from hybrid cars to smart bombs.

But out of sight is out of mind. The renewable energy industry can pretend it is green by hiding this process away in China:

Rare earths aren't found in nature as  separate elements; they need to be extracted from each other, a process that involves thousands (really, thousands) of iterations of boiling the ores in strong acids. There is also almost always thorium, a lightly radioactive metal, in the same ores, and it has to be disposed of. (Thorium leaking into the California desert was a more serious problem at Mountain Pass than low prices.) So ramping up production would mean that Western countries would need to tolerate a level of pollution they've been all too happy to outsource to China.

Thus, both of the investigated coastal plankton communities were unaffected by twenty-first century expected changes in pH and free CO2. This may be explained by the large seasonal, and even daily, changes in pH seen in productive marine ecosystems, and the corresponding need for algae to be pH-tolerant.

Yup.

This is just one of scores of such reassuring studies. Funny how they get such little play in the media.

Ask yourself if you were being paid by taxpayers to play with toys like this...

...whether you would be keen to report that it is a non-problem.

In the final graphical representations of the information contained in our Ocean Acidification Database, we have plotted the averages of all responses to seawater acidification (produced by additions of both HCl and CO2) for all five of the life characteristics of the various marine organisms that we have analyzed over the five pH reduction ranges that we discuss in our Description of the Ocean Acidification Database Tables, which pH ranges we illustrate in the figure below.

The conclusions of the authors:

The results we have depicted in the figures above suggest something very different from the doomsday predictions of the climate alarmists who claim we are in "the last decades of coral reefs on this planet for at least the next ... million plus years, unless we do something very soon to reduce CO2 emissions," or who declare that "reefs are starting to crumble and disappear," that "we may lose those ecosystems within 20 or 30 years," and that "we've got the last decade in which we can do something about this problem." Clearly, the promoting of such scenarios is not supported by the vast bulk of pertinent experimental data.

Two other important phenomena that give us reason to believe the predicted decline in oceanic pH will have little to no lasting negative effects on marine life are the abilities of essentially all forms of life to adapt and evolve. Of those experiments in our database that report the length of time the organisms were subjected to reduced pH levels, for example, the median value was only four days. And many of the experiments were conducted over periods of only a fewhours, which is much too short a time for organisms to adapt (or evolve) to successfully cope with new environmental conditions (see, for example, the many pertinent Journal Reviews we have archived under the general heading ofEvolution in our Subject Index). And when one allows for such phenomena, the possibility of marine life experiencing a negative response to ocean acidification becomes even less likely.

In conclusion, claims of impending marine species extinctions driven by increases in the atmosphere's CO2 concentration do not appear to be founded in empirical reality, based on the experimental findings we have analyzed above.

The whole science behind the extinction crisis is riddled with circular reasoning, but this is an especially fine example. No new research was involved, no field studies, no nothing that involved actual science as we know it. (The researchers for example concluded that habitat loss is one of the "root causes" of global biodiversity loss; this conclusion was derived from the fact that many of the species listed as threatened on the IUCN Red List were presumed to be threatened, and accordingly placed on the list in the first place, because of . . . habitat loss)

Like Steve, I care about extinctions. In my youth I worked on three different projects to try to diagnose and arrest the decline of rare birds in the Indian subcontinent. But like me he fears that mega-political statements and exaggerated claims will only do that cause harm:

By the way, in my earlier post on extinction alarmism, I made the point that exaggerated warnings of impending doom and politicized science "is already causing a dangerous political backlash that has handed ammunition (exactly as in the case of global warming) to those who want to reject any and all evidence of human impacts on the natural environment,"

Precisely. Stop playing into the hands of the nutters.

In the debate over whether our fates as individuals are ruled by nature or nurture-that is, by innate qualities or personal experience-one of the most baffling features is the way the nurture advocates manage to cast themselves as the great foes of determinism. "Genes don't determine who we are," they insist-all the while positing that environmental causes often do. Remember how some Freudians tried to blame autism, schizophrenia and even homosexuality on the way parents treated their children? True, they claimed these effects were treatable, but so are many genetic problems. I wear glasses to correct a partly genetic tendency to myopia.

Nor has environmental determinism escaped moral stain. When Soviet agriculture was forced to obey crank theories that environmental conditioning rather than breeding could determine the frost-resistance of wheat-not coincidentally echoing the notion that human nature could be remade by communism-the result was famine.

Yet the idea persists that paying attention to genetic factors amounts to fatalistic resignation, whereas focusing on an individual's upbringing affirms freedom and opportunity. Thus do certain quarters welcome any chance to knock genes off their pedestal, including a new set of discoveries that go by the name of epigenetic inheritance.

If your father ate fatty food, it turns out, you may be prone to diabetes (so long as you are a rat). This result, recently announced by scientists in Sydney, is surprising because it has long been accepted that mammals are descended from the sperm, not the bodies, of their fathers. One early geneticist even cut off the tails of 1,500 rats over 20 generations to prove that their offspring did not inherit docked tails.

Yet there's already a hint that the Australian result will apply to people. In Sweden, paternal grandsons of men who experienced a particular 19th-century famine in their youth had lower rates of diabetes and cardiovascular disease. So, apart from its possible medical significance, the fat rats suggest a new form of parental influence, probably through small gene-like RNA molecules smuggled into sperm.

If this result stands up, does it turn evolutionary theory and genetic determinism on their heads? If we can inherit some effects of lifestyle, outside the genetic structure, does this free us from the tyranny of genes?

Hardly. It's hard to feel liberated if we get diabetes because of something our parents did before our birth rather than something they were. There are other tyrannies than genetic ones.

The word "epigenetic" is decades old and refers to the switching on and off of genes during development. Some genes get locked down when no longer needed in particular tissues. Cancer cells, for example, lock down tumor-suppressor genes that would normally halt their spread.

One of the chief locking mechanisms is "methylation," the attachment of a chemical block to part of the gene sequence. In the diabetic Australian rats, one gene was nearly twice as active as normal because this process was much reduced. And what makes the proteins that insert or remove these chemical blocks? Our genes. It looks as if some of those proteins, or the RNAs that trigger the manufacture of those proteins, are carried over into the next generation in the sperm or egg.

The new results are evidence that genes are sensitive to experience. But we knew that. From suntan to memory, lots of bodily things happen because genes are activated by environmental triggers: Genes switch on and off in your brain in response to what you perceive, think and do. That's why the old nature-nurture dichotomy is so misleading. Genes are our slaves as much as our masters.

In response to Donald Brown's call for climate scepticism to be classified as a crime against humanity (1st November),

in which he said `We may not have a word for this type of crime yet, but the international community should find a way of classifying extraordinarily irresponsible scientific claims that could lead to mass suffering as some type of crime against humanity':

during all the years that I have argued that green opposition to golden rice perpetuates childhood blindness,

that green opposition to bt-maize and bt-cotton perpetuates pesticide poisoning and is bad for insect and birdlife,

that the greens' biofuels are causing starvation and are bad for orang utans,

that greens' organic farming causes malnutrition and destruction of rain forest because it is land hungry,

that greens' championing of wind power causes fuel poverty and kills eagles,

that greens' obsession with ocean acidification is distracting us from real problems in the ocean

-- during all this time, not once have I called for those with a different point of view to be prosecuted as criminals for their views. Nor would I. Nor would I expect a national newspaper to publish my views if I said something so hateful.

Yet the evidence of `extraordinarily irresponsible scientific claims that could lead to mass suffering' is far stronger in these cases than it is in the case of scepticism that the current warming of the planet is unprecedented, dangerous and mostly man-made.

Yours faithfully,

Matt Ridley.

Today in Beijing an alliance of scientists called Oceans United will present the United Nations with a request for $5 billion a year to be spent on monitoring the oceans. High among their concerns is ocean acidification, which `could make it harder for animals such as lobsters, crabs, shellfish, coral or plankton to build protective shells'.

As opinion polls reveal that global warming is losing traction on the public imagination, environmental pressure groups have been cranking the engine on this `other carbon dioxide problem'. `Time is running out' wrote two activists in Scientific American in August, `to limit acidification before it irreparably harms the food chain on which the world's oceans - and people - depend.'

The trouble is, a shoal of new scientific papers points to the conclusion that this scare is based on faulty biochemical reasoning, unrealistic experiments and exaggeration.

We have been here before. In 1984, acid rain was the environmental scare of the day. As the science correspondent of The Economist, I wrote: `Forests are beginning to die at a catastrophic rate. One year ago, West Germany estimated that 8% of its trees were in trouble. Now 34% are...that forests are in trouble is now indisputable.' Experts told me all Germany's conifers would be gone by 1990 and the Federal Ministry of the Interior predicted all forests would be gone by 2002.

Bunk. Acid rain (though a real phenomenon) did not kill forests. It did not even damage them. Scientists eventually admitted that forests thrived in Germany, Scandinavia and North America during the 1980s and 1990s, despite acid rain. I was a gullible idiot not to question the conventional wisdom I was being fed by those with vested interests in alarm.

Talking of vested interests, the European Project on Ocean Acidification (EPOCA) is now a consortium of over 100 scientists from 27 institutes and 9 countries. This last summer it funded 35 scientists to spend six weeks in the Arctic studying the problem, `assisted' by Greenpeace's ship Esperanza. Think how little incentive the scientists would have to say `sorry, lads, we realize it is a not much of an issue after all'.

Start with a few facts. The oceans are not acid but alkaline, with an average pH of about 8.15 (0-7 being acid, 7-14 being alkaline). But they vary both in space and time, Arctic seas being less strongly alkaline than tropical, and some bays and reefs being actually acid because of underwater volcanic emissions. The dissolution of carbon dioxide in the oceans may lower the pH slightly to about 7.9 or 7.8 by the end of the century at the worst - still alkaline.

Environmentalists like to call this a 30% increase in acidity, because it sounds more scary than a 0.3 point (out of 14) decrease in alkalinity, but no matter. It is still well within the bounds of normal variation over space and time: the pH of the water intake at the Monterey aquarium varies by almost twice as much as this every month. The difference between the pH of the seas off Hawaii and Alaska is greater than this.

Enough numbers. Try chemistry. The scary reasoning rests on the argument that lower pH will mean less dissolved carbonate in the water. But a new paper from scientists in North Carolina proves what many scientists have long suspected, namely that corals and other species do not use carbonate as raw material to make their shells; they use bicarbonate. And dissolving carbon dioxide in water actually increases bicarbonate concentrations.

This may explain why study after study keeps finding that far from depressing growth rates of marine organisms, high but realistic levels of carbon dioxide either do not affect them or increase them. By far the most important calcifiers in the oceans are plankton called coccolithophores, which account for about a third of the total marine calcium carbonate manufacture. There is now strong evidence that coccolithophores are growing faster and larger as a result of human carbon dioxide emissions. Stands to reason if they use bicarbonate.

Studies of oyster sperm, cuttlefish eggs, juvenile sea stars, coral polyps and krill all point to the same conclusion: damage only occurs when carbon dioxide levels reach ludicrous levels, not expected for many centuries. A new study of plankton concluded: `Thus, both of the investigated coastal plankton communities were unaffected by twenty-first century expected changes in pH and free CO₂.'

When I voiced some of these doubts in my book The Rational Optimist, I was accused of cherry-picking studies. All right, so let's take a look at a `meta-analysis', that is to say a comprehensive paper summarising all relevant studies. Iris Hendriks and Carlos Duarte of the Spanish Council for Scientific Research found that in 372 studies of 44 different marine species `there was no significant mean effect' from lower pH. They concluded that the world's marine biota are `more resistant to ocean acidification than suggested by pessimistic predictions' and that ocean acidification `may not be the widespread problem conjured into the 21st century.'

Before I started looking into this, I assumed the evidence for damage from ocean acidification must be strong because that is what the media kept saying. I am amazed by what I have found. Make no mistake: there are lots of threats to the ecosystems of the ocean, from over-fishing to nutrient run-off, but acidification is way down the list. The attention is deflecting funds and action from greater threats. It is time scientists had the courage to admit this.

Last night saw a TV programme in the UK called What the Green Movement Got Wrong, in which various greens admitted that they had done terrible harm by opposing nuclear power and GM food and indoor DDT. It was a pretty good programme, especially on Chernobyl.

But my first instinct was to say would it not be nice if the TV channels gave space to those who got these issues right from the start, rather than celebrating the converts? Or as James Delingpole puts it:

But why, pray, do they deserve any credit for reaching conclusions that those of us who aren't blinkered eco-zealots reached years ago?

What about the hundreds - perhaps thousands - of starving Zambians who died in the 2002 famine when, thanks to the misinformed campaigning of green activists like Lynas, the Zambian government refused to distribute US foreign aid packages of GM food?

What about all the honest, decent scientists and agricultural engineers and nuclear workers whose career path was stymied as a result of green hysteria?

My second instinct was to notice the glaring inconsistency in not even nodding at the possibility that if catastrophic prognostication was wrong for those issues, it might be wrong for climate change too. Or as Delingpole puts it so well:

Had these Greenies been capable of a scrap of insight or self-analysis, they would have understood that the current (now fading) hysteria about AGW comes from exactly the same school of junk science and muddled thinking that gave us Atomkraft Nein Danke and know-nothing idiots in masks and white jumpsuits (Lynas among them) destroying fields of GM crops.

My third instinct, though, is that hard as it is, we must welcome the apostates. Their conversion will do far more to worry the green movement than our effusions.

During the debate programme that came afterwards, Monbiot was allowed to get away with outrageous nonsense that the alarmists are being outspent by the sinister right-wing sceptic conspiracy with its `hundreds of millions of dollars'. He was sitting next to representatives of Friends of the Earth and Greenpeace. The latter alone spends $2.2 billion in ten years!!! Then there is the United Nations, lots of governments, most universities, most big corporations, the Grantham Institute, scores of pressure groups, the BBC, the Guardian, etc etc etc. The alarm industry is far, far better funded than the sceptics.

Some weeks ago I wrote an article for The Times about why I no longer find persuasive the IPCC's arguments that today's climate change is unprecedented, fast and dangerous.

I was delighted to receive a long and courteous letter from David MacKay, the chief scientific advisor to Britain's Department of Energy and Climate Change. With his permission I am publishing my reply to that letter. I would put his letter here too (again he agrees), but I only have a hard copy of it, so that will have to follow when he has time to send me a soft version.Now done.

The remarkable thing about this exchange is that far from weakening my doubts about the IPCC case, it has strengthened them. The letter explains why. Essentially, I have realised that almost the only weapons left in the alarm locker are the retreat of the Arctic sea ice and an event that happened 55m years ago and was probably not caused by CO2 at all. Everything else -- the CO2-temperature correlation in the Antarctic ice core, the hockey stick, storm frequency, phenology, etc etc -- no longer supports the argument that something unprecedented in magnitude or rate is happening. Remarkable.

Here is my letter:

Dear David

I am honoured that you liked my book and I liked yours very much indeed: a brilliant and necessary contribution to the debate. Though it arrived late in my writing process, I managed to squeeze in several references to it in the penultimate chapter of mine.

Thank you for taking the trouble to give such a detailed reply to my Times article - much longer than the constraints of the Times op-ed page allowed for me! I shall now indulge in a longer reply. It is certainly nice that the political `climate' (sic) now allows articles like mine to receive serious replies, rather than accusations of heresy or sin or threats of prosecution as a criminal against humanity. I appreciate that very much. I surmise from your covering note that perhaps your letter is circulated more widely among DECC colleagues and I would be glad for you to circulate this reply, not least to the secretary of state who showed you my article. I shall post this letter on my blog.

I am surprised to find that I agree with much of your letter, but it changes almost none of my conclusions. How can this be? The gap between the science and how it has been presented is huge. This is as much the fault of bodies like the Royal Society, which should have been a brake on politically inspired extreme statements but was not, as it is of the media. You say scientists know how big the uncertainties are and that the failure to ensure that uncertainties are reported has contributed to the problem. I agree and I wish that the science establishment had paid this issue more attention. They allowed and encouraged their spokesmen to peddle the very opposite impression.

Consider this statement for example: `Earth's climate can only be stabilized by bringing carbon dioxide emissions under control in the twenty-first century.' That is the opening sentence of a paper in Nature Geoscience last month.  It is shocking that it got past the editors and reviewers. After 4 billion years of climatic volatility, much of it not caused by CO2 but by orbital variations, solar cycles and so on, how on earth are we to `stabilise' earth's climate by adjusting just one forcing factor? I refuse to accept that the climate could ever be stabilised, let alone by adjusting one factor. That sentence has no place in a scientific journal.

Taking your points in turn, then:

You say most climate scientists are nicer than their caricature on the web. I agree, but so are most sceptics. The image of the politicised, right-wing, anti-science zealot fits some, of course, just as the reverse fits Jim Hansen, Bob Ward and Joe Romm, but the ones whose work I have got to know, such as Andrew Montford and Steve McIntyre are quite different.  The polarisation of this issue is a real problem. I learned from writing about the nature-nurture debate that arguments get polarised because people only read their friends' caricatures of their opponents' works; it is vital that we all read all sides of the argument.

Next you criticise my argument that current warming is not `unprecedented' by reference to the Arctic sea ice graph. But this only goes back to 1979! Blackpool's Football League table position is unprecedented since 1979. In a brief period of warming, of course the warming is unprecedented. You will know the ample anecdotal evidence that Arctic sea ice retreated just as much in the 1920s and 1930s: remember `Warming island' for example. There is also good evidence from wave-made beaches and driftwood in Northern Greenland of probably ice-free summer months in the Arctic 7,000 years ago. A study published in the journal Quaternary Research of sea sediment cores in the Chukchi Sea shelf in the Arctic Ocean concluded that `during the middle Holocene the August sea surface temperature fluctuated by 5°C and was 3-7°C warmer than it is today'. (Incidentally, I am keen to see a proper test of the hypothesis that black carbon is the main cause of the Arctic sea ice summer retreat of recent years and that cleaning up Chinese coal power stations will reverse the trend. The argument seems quite plausible - and it might explain why Antarctic sea ice has been expanding during the same period --  but it needs a test.)

To be honest, whenever that sea-ice graph is used as an argument, I become a little bit more sceptical. If that is the best evidence of something unprecedented, then the case must be weaker than I thought. It is a change that is not even likely to threaten human or animal livelihoods: even with a total late-summer melt (I presume you do not belong to the school of thought that the ice could fail to reform in winter), there is no great albedo feedback at such latitudes because of the angle of the sun in August, and polar bears will expand their range further north or will survive ice-free summer months onshore as they do already in Hudson's Bay, on Wrangel island and parts of Svalbard (where one once walked round my tent while I slept).

Then you say that if I mean `not unprecedented on 100m year timescales'... But those are not the only two options! I mean not unprecedented in centuries and millennia, ie in human history. It is hugely relevant whether the warming of 1910-40 was as fast as 1980-2010 (it was). It is hugely relevant if the climate was as warm in 1100 AD as now (it probably was) both in attributing cause and in making conclusions about sensitivity.

You will have seen this graph, one of many now making it amply clear that the warmth of the Holocene optimum, peaking about 7,000 years ago, was both global in extent and considerably warmer than today:

And this (from "The big picture: 65 million years of temperature swings" by Jo Nova and David Lappi):

Next you disagree with my characterization that recent warming is not `fast'. Phil Jones himself confirms that the rate of warming in 1975-2009 is statistically indistinguishable in rate from the two other periods of warming in the past 150 years: this is from his interview with the BBC -

I contend that none of these rates are `fast'. Contrast them with the rate of change now known from 12,000 years ago, characterized by `local, regional, and more-widespread climate conditions [which] demonstrate that much of the Earth experienced abrupt climate changes synchronous with Greenland within thirty years or less' (Alley 2000. Quaternary Science Reviews 213-226), including `a warming of 7 °C in South Greenland [that] was completed in about 50 years' (Dansgaard, White and Johnsen 1989, Nature 339: 532). That is a change roughly nine times as fast as has happened since 1980 - in Greenland or anywhere else. Another study gives even bigger numbers, saying that the `abrupt warming (10 ± 4 °C)' at the end of the Younger Dryas and the warming at the end of a short lived cooler interval known as the Preboreal Oscillation `may have occurred within a few years' (Kobashi et al 2008 Earth and Planetary Sciences 268:397). Nor was this rate of change confined to Greenland. As one article summarises, `temperatures  from the end of the Younger Dryas Period to the beginning of the Holocene some 12,500 years ago rose about 20 degrees Fahrenheit in a 50-year period in Antarctica, much of it in several major leaps lasting less than a decade.' (Science Daily, Oct 2 1998).

You concede that the rise is running at just 1C per century over the past 50 years, though you do not recognise the degree to which even this is only true of the instrumental record, as adjusted and homogenised by the USHCN and similar bodies. These adjustments have come under question recently since it has become clear that far from correcting for urban warming they seem to be exaggerating it. So the true figure, without adjustments, is probably much closer to that recorded by the SST record and the satellite record, considerably lower than 1C.  Here is the US raw data:

And here it is `adjusted':

The climate is going to have to get a move on if it is hit 3C this century. One-tenth of the century now over and no significant warming yet. This should have been the fastest bit:  since the curve is logarithmic, the first 100 ppm of CO2 should produce as much warming as the next 200 ppm.

You then say we should not be blasé about 2C in 200 years. I am sorry but I do not find this convincing for four reasons:

If anybody had adopted a policy in 1810 to affect the climate in 2010, they would have made absurd decisions because of uninvented technologies, etc.

There is lots of evidence that climate change is positive in its impacts up to 2C, especially if it takes 200 years to get there.

Remember most of this warming is predicted to be in cold regions, in winter and at night. The daytime temperature changes in temperate regions in summer would be less than 2C.

The thing I think we should not be blasé about is the cost of measures we are taking today. Biofuel policies have caused real hunger. Wind power policies have caused real fuel poverty. Yet these measures would do a statistically insignificant asterisk towards solving the problem even if the warming was happening fast. I refuse to be blasé about the jobs not created, the landscapes spoiled, the deaths caused by indoor air pollution in Africa because people cook over charcoal and above all the distraction and diversion of funds from real problems, including environmental ones.

You then ask me what I think the sensitivity to CO2 doubling is and you guess that I must think it is outside the range 1.5-4.5C. Actually, I think there are lots of sensitivities within that range that are `fairly minor problems' and so do many of the studies cited by the IPCC. For Malaria, for example, 2C will produce less than 30,000 extra annual deaths on the million we see today. I think the million is a major problem, the 30,000 in a century's time is a minor problem. Water shortages? The evidence of Arnell 2004 suggests that 2C of warming will reduce the net number of people at risk of water shortage. Etc etc.

So what do I think the sensitivity is? I have no idea. It could be 1C or lower, it could be 3C, but I think it very unlikely from the latest data that it is going to be as high as 4.5C. (Actually, IPCC says that is unlikely, too, if you read the probability right.) I do know this though: the IPCC's estimates of the sensitivity are utterly worthless because they all - all - assume net positive feedback. You are quite right that we do not know that clouds have negative feedback for sure, but there is good evidence that they probably do, and just 2% change in the albedo of cloudiness could reverse all CO2's marginal effect.  And you imply that Spencer is a lonely voice in arguing this case. May I refer you to the Nature Geoscience paper quoted above. Despite its catechistic opening sentence, it goes on to say:

It is at present impossible to accurately determine climate sensitivity (defined as the equilibrium warming in response to a doubling of atmospheric carbon dioxide concentrations) from past records, partly because carbon dioxide and short-lived species have increased together over the industrial era. Warming over the past 100 years is consistent with high climate sensitivity to atmospheric carbon dioxide combined with a large cooling effect from short-lived aerosol pollutants, but it could equally be attributed to a low climate sensitivity coupled with a small effect from aerosols. These two possibilities lead to very different projections for future climate change.

Anyway, you agree that climate sensitivity could conceivably be as low as 1C, which is more than the IPCC does, so I should accept this concession with gratitude and I do. It's a huge change from what was being said by the science establishment two years ago and is still being said by many, namely that 2C is unavoidable.

Then you describe the PETM (it is the Paleocene-Eocene Thermal Maximum - the Pliocene came much later), suggesting that I might not know of it. I not only know it but know the more recent data suggesting that carbon emissions can no longer be reliably interpreted as the main cause of warming then. Gerald Dickens of Rice University last year concluded that CO2 did not even double during the PETM and that something other than carbon dioxide caused much of the heating.

I do think it is revealing how much scientists who are alarmed about climate refer to the PETM. Imagine if the sceptics relied heavily on one episode of uncertain causation and effect, little known and not repeated for 55m years! You would say: is that really the best they can do?

You mention the Toarcian event of 183m years ago, which is new to me, but sounds interesting (by the way I do long to get back to a world where one can discuss paleoclimatic episodes as thrilling stories in their own right without having to draw political lessons from them). Yet the very first abstract I read on the subject after googling it talked about species shifting range in response to `a rapid cooling and their gradual return to former habitat areas in the period of warming'. I will need more evidence that carbon was cause rather than effect here: sounds more like a classic volcanic winter story.

Next you say that sea level is a case where the IPCC has been too conservative. But the graph you show has a trend of 3.1mm per year. This equates to 31cm in a century, comfortably within the IPCC's estimate of 18-59cm in the present century.

Let me make two final points. I have argued that the two main examples you cite - the Arctic sea ice retreat and the PETM - are weak examples on which to build your case. Five or ten years ago I suspect that you would have cited the Vostok ice core record, showing CO2 and temperature in lockstep, and the Hockey Stick graph, showing recent temperature rises to be unprecedented in a thousand years. These two graphs were very, very important in persuading me to rejoin the consensus view in the mid 2000s, after I had moved towards cautious scepticism in the late 1990s. The fact that both are now discredited as evidence of CO2 attribution has been very, very important in sending me back towards scepticism. When the facts changed, I changed my mind. The Vostok graph now unambiguously shows that CO2 rises follow rather than precede warming. The impact of that discovery is huge. The Hockey Stick graph is largely a statistical artefact caused by the inappropriate use of short-centred principal component analysis and heavily reliant on geographically narrow and methodologically suspect samples of tree rings. If you have not read Andrew Montford's The Hockey Stick Illusion to understand this, I do beg you to do so.

My last point is this. We always discuss climate change in isolation, as a unique issue. Yet we cannot ignore the history of past environmental alarms, which I catalogue in my book: on population, famine, pesticides and cancer, desertification, sperm counts, acid rain, GM crops, and many other issues, we have been promised catastrophe, often with the backing of peer-reviewed science, and repeatedly these hopes have been dashed. (You may need to remember to switch your sarcasm detector on when reading the last sentence.) My position is heavily influenced by having been science editor of The Economist during the acid rain scare and having been a full-scale alarmist at the time myself.  In 1984 I wrote: `Forests are beginning to die at a catastrophic rate. One year ago, West Germany estimated that 8% of its trees were in trouble. Now 34% are...that forests are in trouble is now indisputable.' Experts told me all Germany's conifers would be gone by 1990 and the Federal Ministry of the Interior predicted all forests would be gone by 2002. I was wrong. German forest biomass increased during all these years. Of course, the boy who cries wolf may be right one day. But we are right to grow more sceptical when he keeps being wrong.

Now, if for the past 20 years we had been told that there is a probability of some change in the climate due to CO2, and a very small possibility that it is likely to lead to a drastic lurch, then I could join with you and the consensus. Instead of which I have been repeatedly told that trillions must be spent urgently because there are only a few months to save the world and it is the most urgent problem, more urgent than hunger, malaria and indoor air pollution, likely to lead to the collapse of the entire economy and moreover that the science is settled and to question it is to be equivalent to a criminal. So, apologies if I sound a little exercised on this, but as a huge champion of science I feel very, very let down by the science establishment, especially the laughably poor enquiries on the emails published this year. Ask yourself if these emails had been within a drug company about a drug trial, whether the establishment would have been so determined to excuse them.

Again, I thank you for the courtesy of a proper reply. This is more than I get from most scientists and journalists on this topic. I do not envy the difficult decisions you and your political colleagues face, but I do beg you to review the latest evidence and increase your doubts about the likelihood of catastrophe; also to increase your concern for the costs and damages caused by renewable energy policies.

yours sincerely

Matt

Despite conceding the factual truth of my article in detail, they tell me to brush up on chemistry then give no examples of me getting anything wrong.

They concede my point that any shift of acidity will be within natural ranges. Thanks. But say it could be much larger `in the future'. No numbers, note. They mean in several centuries.

They concede my point that some organisms make shells form bicarbonate. Thanks. But they say falling carbonate levels could dissolve shells. At what levels?

They concede that it is `true' that there is no net effect of carbon dioxide on organisms. Thanks. But say there will be `winners and losers'.

They mutter about `unpredictable consequences' of `change'. No! You don't say.

All this is very, very different from the exaggerated claims that I was attacking. It is a huge retreat, under a smokescreen of insult.

I'm rather pleased.

(I have gone to weblinks for his charts and in one case come up with a slightly different version -- the sea ice graph I could not find the exact one he included so I have found another from the same source which has more years on it than his version, but it's the same data and the same source.) Update: all graphs now correct!

Once more I thank David for the exchange, and for his willingness to address the issues I raise. He's welcome to write here again in response to my response.

Matt

Dear Matt,

I'm writing in response to your recent article in the Times, which was passed to me by our Secretary of State.  Reading your article, I enjoyed and fully supported your insistence that science should be transparent, and that decision making should be based on a calm assessment of credible science. Providing honest advice based on robust science is a key responsibility in my role at DECC.  I have lots of time for scepticism, because I'm a scientist, and scepticism is the bread and butter of science.

I'm not a climate scientist. But I have spent quite a lot of time in seminar rooms with real climate scientists over the last few years, and I have to say that my impression of that scientific community is that it is in a healthy state, quite unlike the caricatures in some of the media and blogs (which allege they are secretive, dishonest data-manipulators, etc). The community seems healthy in the sense that the scientists are open; they are critical of their own community's work; they highlight weaknesses in colleagues' presentations and models and papers; and they criticise everyone - the IPCC, Al Gore, and Nigel Lawson alike - for inaccuracies or simplifications in any direction. In particular I have always noticed that the climate science community knows how big the uncertainties in climate science still are. Sadly, some science communicators and policy people seem to find it difficult to communicate this aspect of the science. The media machine seems to prefer to turn the normal scientific process of slow and iterative development of understanding into a series of 'headline new findings', which focus on disagreement. For example, if one group of scientists report that

'sea level could rise by 0.3-1.3 m this century',

this can lead to a headline of 'sea level to rise 1.3 m shock!'. (Note the omission of the uncertainty.) And, if the following week another group of scientists describe results suggesting that

'sea level could rise by 0.28-1.28 m this century',

it's easy to imagine a headline of 'sea level rise has been exaggerated, new report says it will be as little as 0.28 m'. I mention this issue of uncertainty-reporting because I think the failure to ensure the public discussions of climate change have included the uncertainty, and the failure to express decision-making in terms of risk-management, have contributed to the current climate-policy congestion.

But rather than discuss scientists and the media, what I'd really like to discuss is the science. It would be great if we could find agreement on the science, and I am optimistic that we can.

"I'm not a denier: I think carbon dioxide is a greenhouse gas. I'm not even a sceptic (yet): I think the climate has warmed and will warm further. But I am now a "lukewarmer" who has yet to see any evidence saying that the present warming is, or is likely to be, unprecedented, fast or tending to accelerate. So I have concluded that global warming will most probably be a fairly minor problem - at least compared with others such as poverty and habitat loss - for nature as well as people."

OK. First, "unprecedented" and "fast" - these terms are ill-defined, so are tricky to discuss.  If "unprecedented" refers to recent human timescales, I'd suggest that the data do show that something unprecedented is going on. Look at the data on Arctic sea ice, for example. Here's the latest graph from Boulder:

For most of the summer of 2010, the arctic sea ice extent has been about four standard deviations below the 1979-2000 mean. The summer ice extents in the years 2007, 2008, and 2009 were all more than two standard deviations below the mean. I find these sorts of data compelling.

If however "unprecedented" means "the current warming is unprecedented on 100-million-year timescales" then I would absolutely agree - as I'll elaborate later, there have been natural warming events that have been roughly as fast, and that led to significant and lasting climate change and mass-extinctions. So, yes, there is a precedent, but the precedent doesn't make for comfortable reading!

What about "fast"? I don't know how to define "fast", so let's talk about the numbers. The measured warming rate is about 0.8 degrees C per century, over the last century, and 1.1 degrees C per century, over the last half century (plus or minus error bars). Is 1 degree per century "fast"? Maybe the right thing to do is to focus on consequences. If we assume, just for the sake of argument, that the warming continues at this rate of 1 degree per century for another century, then the people of 2100 will be saddled with a two-degree world. Whether or not we call that warming rate "fast", a two-degree world has global consequences about which I would not want to be blasé.

Is the warming "tending to accelerate"? Here, I definitely agree with you that there is no clear evidence that warming is "accelerating", but equally there is also no clear evidence that it isn't. The natural fluctuations are too big to tell; it's already hard enough to get a good measurement of the first derivative, let alone the second derivative!

Let's move to your conclusion, that climate change will likely be a "fairly minor problem". I'd like to challenge this in two ways.

First, I'd like to consider what the value of the climate sensitivity parameter might be. (That is, the long-term warming response to a doubling of carbon dioxide.)  The consensus of the climate science professionals is first, that this parameter is still very uncertain, but second, that it probably lies somewhere between 1.5 degrees and 4.5 degrees C, with a most probable value in the neighbourhood of 3 degrees C. Now, is there any value in this range (1.5-4.5 C) that you would judge to be a "fairly minor problem"? I assume not, but do correct me if I'm misintepreting. So I take it that what you are judging from the evidence is that the consensus is wrong; and that you are confident, based on the evidence, that the climate sensitivity is less than 1.5 degrees - perhaps something like 1 degree or so? I don't want to put words in your mouth, but would like to clarify what I understand you to be saying. This climate sensitivity of 1 degree C does have a rational basis, namely, it would be the sensitivity if there were zero net feedback from a carbon-dioxide forcing to other warming effects - it's the warming of the system if CO2 were doubled, and nothing else happened. So if you believe that "it's a fairly minor problem" because you are convinced that the sensitivity is about 1 degree, I guess you're saying that you judge the sum of all the feedbacks to be roughly zero; whereas in contrast the consensus of the climate scientists is that the sum of all the feedbacks is significantly positive, albeit with large error bars.  [A cartoon of why the feedback is expected to be significantly positive: one dominant response to warming is that warmer air holds more water vapour; and water vapour is a strong greenhouse gas (stronger than CO2); so there is feedback from warming (caused by CO2 or any other forcing) to more warming (by water vapour). Some evidence for this physical model comes from the fact that computer models of atmosphere and ocean reproduce this effect and thus fit the last hundred years of global data pretty well.]

The view that the sum of the feedbacks is not significantly positive but is near zero or even negative isheld by a small number of climate scientists - for example, Roy Spencer, an atmospheric scientist who specialises in satellite observations. His view that the feedbacks are not large and positive is based on a belief that clouds contribute a big net negative feedback. It's widely agreed that clouds are one of the least-well-understood parts of the system, so this is conceivable. Now, the smaller (or more negative) the feedback is assumed to be, the less of the 20th century warming can be attributed to human effects, and the more of it must be attributed to natural fluctuations. The consensus view is that it's hard to see how natural fluctuations could account for most or all the warming, but I would agree that it is conceivable that the computer models have not yet adequately captured natural fluctuations.

Where am I going? Well, I'm trying to quantify your view, as I understand it, which is that the climate sensitivity might be only 1 degree C or so, and I want to agree that, yes, this is conceivable, and it's a possibility that is indeed consistent with published climate science - climate scientists all agree that there remain significant uncertainties about clouds and about natural fluctuations, and the error bars on the climate sensitivity are large. So I agree with you about this possibility; what I don't understand is how you can feel so sure that the climate sensitivity is only about 1 degree C. All the climate professionals I've spoken to think it's more probable that the climate sensitivity is significantly bigger than 1 degree C, and they do have a detailed physical account of why they believe this. My non-expert view would be that yes, a sensitivity of 1 degree C is conceivable, but so is a sensitivity of 2 or 3 or even 4 degrees.

The second tack I'd like to take is to point you to evidence that supports the view that climate change might be more than "a minor problem" - evidence that supports the proposition that the sensitivity is greater than 2 degrees. It's possible you haven't heard about this evidence, since the mass-media reporting of climate science rarely goes into any scientific detail, so it is a story that only a few lay-people are aware of.

The evidence is from geology, from events that happened millions of years ago. For our convenience, nature has already carried out experiments to test what happens when a trillion tonnes of carbon are released in to the atmosphere over a brief period, and the results of those experiments can be read out of the rocks.

This photo is of a 55-M year old sedimentary rock core from the North Atlantic, on which the publication of Norris and Röhl (1999) was based. [Nature 401, 775-778.]

(The original image is available at http://www.inference.phy.cam.ac.uk/sustainable/images/geology/Figure7.3.L.jpg in case this reproduction doesn't come out well.)

With the naked eye you can see near-periodic bands of lighter and darker colour. These bands match Milankovic periods of 20,000 years or so (the period of some of the Earth's orbital wobbles) and allow the events recorded in the rocks to be dated with great precision. Based on measurements of isotope concentrations in these and other rocks, the reconstruction of the PlioPaleocene-Eocene thermal maximum (which falls at one end of this rock core) runs as follows: first, from a natural source - either mega-volcanoes or within-ocean-floor deposits or both - a large release of carbon took place, over about 1000-10,000 years: perhaps about one trillion tonnes of carbon. (For comparison, human emissions have passed 0.5 trillion tonnes, and are heading for one trillion tonnes within a few decades.) The source of this carbon was probably in the vicinity of the North Atlantic. In response, a large global climate change happened, with temperatures rising by more than 4 degrees C, and there was a mass extinction, with lots of species wiped out, and widespread anoxic and acidic conditions in the oceans. This climate change blip lasted about 200,000 years before natural processes restored carbon levels and temperatures to roughly what they had been before.

For an accessible account of this discovery by the President of The Geological Society (a formerly sceptical oil-explorer), I recommend "Challenged by Carbon" by Bryan Lovell (CUP 2010).  This evidence caused Bryan Lovell to change his mind on climate change.

In case a single experiment does not convince, nature has repeated the test, and there is another event, the Toarcian, which took place 183 M years ago in the Jurassic. The data can be gathered from places like Robin Hood's Bay in Yorkshire. I learned about this just this week. Again, there was a natural massive carbon release, probably triggered by a mega-volcano (the associated basalts go by the name of Karoo Ferrar, and had a volume of 2.5 million km3), after which there was an immense anoxic event in the oceans, severe global warming, and a mass extinction (the Pliensbachian-Toarcian extinction). In addition, based on measurements of strontium in fossils, it's deduced that during the period of global warming, weathering rates increased to four times normal, showing that rainfall patterns were radically changed. The temporary global temperature rise was believed to be about 6-10 degrees C.

Finally, I was interested to read your comments on the IPCC's structure and processes. While I won't address them here (noting that DECC has made a full response to the InterAcademy Council's report ahead of IPCC's imminent Plenary), I think it is worth noting that there are some headline issues where the IPCC cannot be accused of exaggeration. Sea level rise is a good example, where we can compare an IPCC projection with subsequent data. The IPCC's Fourth Assessment Report estimates of global average sea level rise by 2100 were conservative because they omitted the potential contributions from polar ice sheets. Subsequent data on sea level (previous page, right) show that actual sea-level rise falls at the upper range of the IPCC's projections (shown by the dashed grey lines). [Source: Stefan Rahmstorf, et al. SCIENCE 316 4 May 2007. p709.]

Can I thank you again for your engagement with these issues. I'd be delighted to discuss them further if you wish.

Yours,

David MacKay FRS

Chief Scientific Advisor, DECC

Contrast the multitude of different market-generated and voluntarily adopted ideas with the ideas of progressives - for example, progressives' idea thatgovernment must regulate the fat content of foods.

Each of us can decide how much we value, say, juicy burgers and double-dark chocolate ice cream compared to how much we value a trim waistline and longer life expectancy. And each of us values these benefits differently. The dietary choices that I make for myself are right for me, but I cannot know if they are right for anyone else. Progressives, in contrast, falsely assume there's a single correct metric, for the whole country, that determines for everyone how to trade off the satisfaction of eating tasty but fatty foods for the benefit of being healthier.

It's in this way that progressives' ideas are indeed big and bold - for these ideas are about how millions of other individuals should live their lives. In practice, these are ideas about how one group of people (the politically successful) should engineer everyone else's contracts, social relations, diets, and even moral sentiments.

I never cease to be astonished by the paternalist instincts of most bien-pensant intellectuals on things like diet. This word `progressive' is problematic, though. I insist I am a progressive: I think progress is a good thing, socially as well as economically. But to most it seems to mean getting the state to do things. We've been trying that since the Bronze Age and it keeps ending in tyranny and stagnation.

The paleontologist who made this discovery told Science News:

"We were expecting to find rapid extinction, a total change in the forest," says study leader Carlos Jaramillo, a biologist at the Smithsonian Tropical Research Institute in Balboa, Panama. "What we found was just the opposite - a very fast addition of many new species, and a huge spike in the diversity of tropical plants."

So here is what we know about the PETM:

- the warming was gradual, about 5C over 10,000 years. That's about one-five-hundredth of the speed of warming at the end of the last ice age

- carbon dioxide levels increased but probably did not double

- tropical forests thrived

- it was 55m years ago when all sorts of things were different, including the shape and position of the continents

- nobody knows what caused it

And yet we are asked to believe that this is one of the strongest arguments for spending trillions of dollars that could be spent on allevi

A Haitian who survived the January earthquake and has so far escaped cholera recently told a reporter that this month's Hurricane Tomas wasn't as bad as he thought it would be, "thank God." I know it's often just a verbal tic, but it has always struck me as odd that people who survive natural disasters thank God for saving them but rarely blame Him for the disaster.

It has been quite a decade for natural disasters: the Indian Ocean tsunami, Hurricane Katrina, Burma's cyclone, Pakistan's floods, China's quake. Only once to my knowledge has there been much media debate about whether these disasters were "acts of God"-after the Indian Ocean tsunami of 2004, perhaps because it happened on the day after Christmas. In any case, I always felt the phrase applied better to 9/11, considering the motivation of the terrorists.

The belief in a benevolent deity who nonetheless allows disasters struck Voltaire as odd, too. The Lisbon earthquake of 1755-in which up to 60,000 people died in quake, fire and tsunami-provoked him to write a poem railing against the theological view that the disaster proved the deity benevolent after all, because Lisbon had earned its punishment through sin. What did God have against the Portuguese, wondered Voltaire: "Was then more vice in fallen Lisbon found,/Than Paris, where voluptuous joys abound?"

Lisbon also led Voltaire to ridicule the philosophy of optimism, a word coined in 1737 to describe Gottfried Leibniz's view that God had made this the best of all possible worlds (and, therefore, the future could be no better). In Voltaire's novel "Candide, or the Optimist," Dr. Pangloss remains blissfully confident-despite experiencing syphilis, shipwreck, earthquake, fire, hanging and slavery.

Yet the natural disasters of recent years have strongly vindicated optimism-not of Leibniz's variety but of the modern, hopeful kind. The difference between Haiti's death toll of up to 300,000 in January and Chile's of about 500 a month later can be attributed in large part to the difference in their wealth. Likewise, Category 5 Hurricane Dean struck the well-prepared Yucatán in 2007 and killed no one, but when a similar storm struck impoverished and ill-prepared Burma the next year, it killed 200,000. Pakistan's floods this year killed 1,800; Poland's, less than 50. Java's Mount Merapi has killed more than 200; Iceland's Eyjafjallajökull killed no one.

In short, prosperity buys survival. (The shocking thing about Hurricane Katrina was not that it killed so many people but that it did so in such a prosperous country.) The scholar Indur Goklany has calculated that, as the world has grown richer in the past 90 years, the number of annual extreme-weather deaths has fallen 93%, despite a quadrupling of the population and an increase in the (recorded) number of such events.

Suppose world per-capita income were to octuple in the next 90 years, as it did, roughly, in the last 90. So long as countries like Haiti get their share of this prosperity, we can expect most of the world to become as nearly disaster-proof as the rich West is today: through building standards, warning systems, health and emergency services, and technology. A mega-volcano or a big asteroid would still test any country, but much less pain would come from providence speaking (as the old hymn has it) "through the earthquake, wind, and fire." A thought for Thanksgiving.

Over the past 200 years, Malthusians have tended to look at people as simply the users-up of scarce resources. They have tended to view nature as the producer of things and mankind as the consumer of things. And their view of people as little more than consumers - almost as parasites - inevitably leads to them seeing human beings as the cause of every modern ill, and therefore reducing the number of human beings as the solution to every modern ill. Their focus on finiteness means they conceive of humanity as a kind of bovine force, hoovering up everything that it comes across.

I read this while sitting in a hotel room at San Francisco airport. Huge jets queue for take off in full view of my window. I am in the middle of a great conurbation. But between me and the jets lies a stretch of water, an arm of the Bay itself. And the water is a bird watcher's paradise. There are rafts of ducks such as buffleheads and wigeon. There are pelicans, grebes and two speces of gull. Along the shore there are great white and little egrets, willets, whimbrels, grey plovers, stints, dowitchers, avocets, yellow-legs and tight flocks of sandpipers. Sea lions cruise a litle further out, and an osprey has just plunged into the water after a fish.

My point? The water is presumably `polluted' by humankind with nitrogen and phosphorus from farming and sewage run-off, or `enriched' as it is sometimes called. Without people I doubt these would be nearly as much birdlife here. People enhance the productivity of natural ecosystems as well as agricultural ones.

I'm quoted [in the press release] as saying, among other things, that this study helps 'rehabilitate' Neanderthals by showing that they were able to develop some of the accoutrements of behavioral modernity independent of any contact with modern humans. While I've caught a bit of flak from some friends and colleagues for that turn of phrase, I stand by my statement -this study helps to cast Neanderthals in a much more positive light than they have been for a long while now.

In my book, I argue that Neanderthals --though highly intelligent -- did not show a tendency to innovate, because they did not show a tendency to exchange (their artefacts never come from far away), and this kept their toolkit much the same till the end. The discovery of Neanderthals innovating would therefore be a blow to my argument.

I'm not yet convinced that the Uluzzian technology Riel-Salvatore describes was made by Neanderthals at all. Nor is he:

I'm the first one to admit that the fossil evidence for the 'transition interval' in Italy is extremely scant. The attribution of the proto-Aurignacian to modern humans is based on a couple of loose while the attribution of the Uluzzian to Neanderthals is based on three milk teeth from two layers in one site, Grotta del Cavallo. The only certainty seems to be for central Italy, where Neanderthal remains are associated with some of the Late Mousterian assemblages. In the past, the consensus view - no doubt in part informed by the Chatelperronian situation - has been that some of those teeth from Cavallo display some affinities to Neanderthals, in spite of the lowermost tooth originally having been described as more modern in appearance (Palma di Cesnola and Messeri 1967), although recent revisions suggest that it falls within the Neanderthal range (Churchill and Smith 2000).

Whatever the case may be, the fossil record is extremely thin here, and while people have traditionally been comfortable with the proto-Aurignacian = modern human and Uluzzian = Neanderthal equations, my own preference is to remain agnostic about who made what industry during the transition interval in the Italian peninsula (Riel-Salvatore 2009). However, because the generally accepted view is that the Uluzzian was made by Neanderthals, I've used it as an operating assumption in this new paper, even though I derive none of my hypotheses from that assumptions. In fact, I think that considering whoever made the Uluzzian first and foremost as foragers helps to avoid predetermining interpretations about what the Uluzzian was, how it came to be and how it disappeared.

Moreover, I don't find his argument for what triggered this burst of innovation persuasive. He blames it on an unusually volatile climate around 42,000 years ago:

Overall then, what I'm proposing in this paper is that climatic instability selected for behavioral innovation, one manifestation of which was the Uluzzian in southern Italy. If Neanderthals are responsible for the Uluzzian, that means they reacted in very 'modern' ways to these conditions by developing some of the very same innovations that seem to have made modern humans so evolutionary successful in the long ter

This meme just won't die. Even evolutionary biologists like it, arguing that the volatility of the Pleistocene in Africa selected for big brains in human beings -- even though it did not do so for any other mammal species. The actual empirical evidence for a volatile climate triggering innovation at any point in history or pre-history is non-existent. Places with the most volatile climate, like Australia, saw slow innovation rates, not fast. The settled climate that came after the ice age, not the wild swings of the last glacial maximum, caused a burst of innovation, especially in agriculture all over the world (see Richerson, Boyd and Bettinger's paper entitled `Was agriculture impossible during the Pleistocene but mandatory during the Holocene).

Until there is actual empirical evidence to the contrary, I will continue to think that the inventiveness of people comes from demographic density and frequent exchange, not from some fanciful climate determinant.

Oh, and until there is better evidence than three milk teeth I will continue to think that the Neadnderthals did not invent the Uluzzian technology.

I am glad to have my main point confirmed by the reply: that there is in fact no evidence for net biological harm likely as a result of realistic changes in ocean pH. This is a huge and welcome change from the exaggerated rhetoric that has been used on this topic.

The reply also confirms the accuracy of virtually all of my factual assertions about the likely change in pH, the natural variation in pH and other issues, including the involvement of a Greenpeace ship in a research project. Only my interpretation is challenged.

The reply goes on to say that `positive and negative impacts do not cancel out, but both contribute to ecosystem perturbation'. This strange remark flies in the face of everything that ecologists have been discovering ever since Charles Elton coined the term, namely that ecosystems are dynamic, not static entities. It amounts to saying that change is bad because it is change. That is a ciurcular argument.

2nd Update: I am told 270kg of Nd per megawatt is about right, though it will vary with different kinds of magnet. That means about 675kg of Nd in a 2.5MW turbine. Hat tip Alan Bates.

Today Times has an op-ed article by me on shale gas, behind a paywall. And there is an article with a similar import today in the National Journal, which includes this political point:

The State Department, meanwhile, sees geopolitical opportunities in the prospect of newly accessible natural-gas resources around the world and aims to make the most of them. By promoting new methods of exploration and extraction, it seeks to make other countries less dependent on imported natural gas. In India and China, in particular, the State Department hopes that new discoveries of gas deposits could replace coal and reduce emissions from coal use.

Here's the whole of my article:

The death of 29 men in the Pike River Mine is a reminder that our hunger for energy can be fatal. Mining coal, still our biggest source of electricity, is dangerous and dirty. So when a safe, clean, cheap and abundant alternative - shale gas - is available surely we should exploit it?

Not according to Chris Huhne, the Energy Secretary. "Left untouched, the electricity market would allow a new dash for gas, increasing our dependence on a single fuel, and exposing us to volatile prices. It would lock carbon emissions into the system for decades to come."

Whether Mr Huhne likes it or not, a dash for gas is coming. What's more, it is almost all good news. The discovery of how to exploit huge global reserves of gas encased in shale rock is causing epochal change in the energy scene. Shale gas is like any other gas except that it is everywhere: from Poland to Pennsylvania, from Queensland to Sichuan. There is even some in the Wirral and the Weald, but don't hold your breath that the Nimbys will let much be tapped.

America, where the shale gas revolution began, has 50 years, probably more, of increasingly cheap supplies. The US is not just turning away liquefied-natural-gas tankers from Qatar (hence the current low price of gas), but considering turning gas-import terminals over to exports. Shale gas is popular with those who do not like being dependent on Putins and Ahmadinejads, so unpopular with those two martinets. Dreams of a gas Opec, in which Russia and Iran control more than half the world's supplies, are evaporating. Thus, far from increasing dependence on volatile foreigners, a dash for gas means tapping into a diverse world market - especially if we invest in storage facilities.

For a glimpse of a truly scary future dependent on volatile suppliers look no farther than Mr Huhne's favoured technology, wind. Every wind turbine has a magnet made of a metal called neodymium. There are 2.5 tonnes of it in each of the behemoths that have just gone up to spoil my view in Northumberland. The mining and refining of neodymium is so dirty (involving repeated boiling in acid, with radioactive thorium as a waste product), that only one country does it: China. This year it flexed its trade muscles and briefly stopped exporting neodymium from its inner Mongolian mines. How's that for dangerous reliance on a volatile foreign supply?

Besides, wind does nothing to reduce carbon emissions. As Robert Bryce shows in his book Power Hungry, even Denmark, which can switch off imported Norwegian hydro power when the wind spins its many turbines, has failed to save any significant net carbon emissions through wind. The intermittent nature of the wind means that fossil-fuel power stations have to be kept going, or inefficiently powered up and down. Besides, the total power produced from even the biggest wind farms is so small that, as a strategy for reducing carbon emissions significantly, wind power is a failure.

Yes, gas has carbon in it, but half as much as coal for each unit of energy. So a dash for gas to replace coal would dramatically and rapidly reduce carbon emissions. Given Mr Huhne's nuclear allergy, it is probably by far the most effective and low-cost way to do so. Solar is expensive (and strangely inefficient at night); tidal destroys ecosystems; wave is an engineering nightmare; there is no room for more hydro; and biofuels use just as much fossil fuel in their production as they produce in "green" fuel.

Shale gas has environmental risks - the water and chemicals used in the hydraulic "fracking" process must be safely disposed of - but environmental benefits too. Unlike renewables it is not land-hungry, taking up remarkably little space. A typical shale gas well has a footprint one 3,000th of the size of woodland producing the same amount of energy in firewood. Unlike coal and biofuels, it does not require transport by road and rail as it can be piped. Unlike oil, it cannot spill (and though it can explode, it rarely does). Unlike coal, its turbines work at small scale almost as efficiently as at large scale, so power stations can be many and local, supplying heat as well as electricity. It can be burnt near where people need power, requiring less investment in ugly pylons and transmission lines. Unlike coal it does not emit sulphur, mercury or other pollutants.

A few decades of emphasising natural gas at the expense of coal would reduce costs, carbon emissions, pollution, congestion, land use and reliance on volatile regimes as well as keeping the lights on.

The chief reason that living standards shot up in the industrial revolution was cheap energy. Coal had a peculiar property that marked it out from wood, wind and water: it became less costly the more of it you dug up. The drop in the price of energy compared with labour spurred the replacement of toil with automation, thus collapsing the price of fulfilling human needs and desires. Gas looks by far the best way to keep energy cheap and make it cleaner over the next few decades. In your quest for perfect carbon-free energy, Mr Huhne, do not dismiss lower-carbon gas - do not, in Voltaire's phrase, make the best the enemy of the good.

Update: here are some readers' letters about our exchange.

I've never arm-wrestled Bill Gates, but we have now had a good natured debate in the pages of the Wall Street Journal.

Here's his effort, and here's mine.

A quote from his:

Although I strongly disagree with what Mr. Ridley says in these pages about some of the critical issues facing the world today, his wider narrative is based on two ideas that are very important and powerful.

A quote from mine:

I am certainly not saying, "Don't worry, be happy." Rather, I'm saying, "Don't despair, be ambitious"-though I admit it's not nearly as snappy a song lyric.

Can it really be easier to raise money for a wildlife conservation project in Madagascar or Galapagos when everybody is saying that the major threat is not habitat loss or invasive species, but slow warming?

Can it really be helpful for bird conservation when green groups take money from wind companies which kill golden eagles?

Can it really be helpful for rainforests when pressure groups support biofuels that then destroy orang utan habitat?

Can it really be helpful for fish and coral conservation when so much money gets spent on ocean acidification instead of overfishing?

I would like to hear from some conservationists who feel this way, even secretly.

Here's a fine essay from the Globe and Mail by Margaret Wente that makes the same point. An extract:

Before they were sucked into the giant vortex of global warming, environmentalists did useful things. They protested against massive Third World dams that would ruin both natural and human habitats. They warned about invasive species and diseases that could tear through our forests and wreck our water systems. They fought for national parks and greenbelts and protected areas. They talked about the big things too - such as how the world could feed another three billion people without destroying all the rain forests and running out of water. They believed in conservation - conserving this beautiful planet of ours from the worst of human despoliation - rather than false claims to scientific certainty about the future, unenforceable treaties and radical utopian social reform.

I have an op-ed in today's Times on the subject of whether the man-made climate signal is going to be visible against the weather noise. Here is the gist of it, with some links.

I have just cleared fresh snow in my back yard for the ninth day in a row. Powder lies 13 inches deep on my lawn: I probed it with a tape measure. Ten years ago David Viner, a climate scientist from (inevitably) the University of East Anglia, told us that within a few years winter snowfall would become `a very rare and exciting event' and that `children just aren't going to know what snow is'. My children have seen more snow in Northumberland in the past 11 months than I had before in any year of my life.

That's not a trend. It's not climate change. It's weather: just a cold snap. But that's the point: the climate is just not changing very fast. We have now had a third of a century of man-made warming. This was meant to be the fastest bit - the curve is logarithmic - and yes, it has warmed, but not even enough to make winter noticeably different from 1978, let alone cause catastrophe.

Last week saw the coldest 28thNovember Britain has ever experienced, and Wednesday was the coldest 1st December. By contrast we have not broken a heat record for a particular date since 10 May 2008. Yet, with weary predictability, in October the Met Office's shiny new £33m supercomputersaid there was a high probability of a warmer winter for the east of England and Scotland, just as it did last winter and the one before, with a `barbecue summer' in between. They should ask for their (or rather our) money back at PC World.

The climate `experts' sternly admonished anybody who even hinted that last winter's cold might not fit the global warming creed. `It is really stupid,' said Peter Inness of Reading University in January, `to say that the current cold weather proves that climate change is not happening.' Yet when somebody prays in aid the Pakistan floods, Hurricane Katrina, or the hot summer of 2003, you hear not a peep of complaint from the scientific establishment. When it is cold, it is just weather. When it is warm or stormy, it is `linked with climate change'.

Case in point: Oxfam's shiny new £40,000-a-year `climate change press officer' (I saw the ad) said this week that climate talks are urgent because `21,000 people died due to weather-related disasters in the first nine months of 2010 - more than twice the number for the whole of 2009'. This is blatant cherry-picking. Take less than one year's number, compare it with one other year's number and draw a trend? Seriously? Even though the events in question have - they admit - no proven connection with climate change, only with weather? And expect reporters to fall for it? (Oh: they did?)

You probably got the impression from the Oxfam press release that weather-related deaths are on the rise, maybe even at an all time high. Let us look at a longer trend to see if this is true. That figure of 21,000 weather-related deaths is lower than the annual average for the nine years 2000-2008: 35,000. It is also lower than the annual average in the decade before that: 33,000; or the decade before that: 66,000; or the decade before that: 54,000, or the decade before that: 168,000.

You get the gist. The average number of people dying each year in weather-related events has been going down ever since the 1920s, when it stood at a terrifying 485,000 a year. It is down by 93% since then, or 98% as a proportion of the population. (In the decade 1910-1919, the average yearly death rate was supposedly about as low as 2010 - but one suspects statisticians had man-made disasters on their minds then.)

The reason for the huge fall in the death rate from weather over the past century is not that the weather has changed but that the human world has changed. Better transport now enables supplies to reach people affected by droughts, better housing enables people to survive storms and better communication enables people to escape floods.

When a cyclone hit impoverished and despotic Burma in 2008, it killed 200,000 people, whereas an equally strong one in middle-income Mexico the year before killed nobody. In the same way, this week's snowstorms would have killed thousands of rural vagrants before the eighteenth century, and starved thousands of peasants when their cattle died. Economic development is what helps human society to adapt to weather and is what will help it to adapt to climate too.

His TED talkwas amazing and I have since shared some very enjoyable connversation with him over Chinese food in Newcastle.

Here is what I wrote:

Everybody knows that the Internet will transform education, but nobody yet knows how. Most of the models sound like dull attempts to reproduce, at a distance, the medieval habit of schooling-one teacher telling a bunch of children what to think. Now, though, I think I have glimpsed a better idea: the self-organized learning environment (SOLE).

The credit for this approach belongs to Sugata Mitra, an Indian physicist who, a decade ago, began to install public "hole in the wall" computers in the streets of Indian slums. He then sat back and watched how quickly the impoverished kids learned to use the technology. The experiment, which has now gone global, inspired the book that inspired the film "Slumdog Millionaire," in which a boy from the slums improbably learns enough to win a TV quiz show.

Dr. Mitra's next brainchild, SOLE, takes this dynamic into the classroom. He is convinced that, with the Internet, kids can learn by themselves, so long as they are in small groups and have well-posed questions to answer. He now goes into schools and asks a hard question that he thinks the students will not be able to answer, such as: "How do you stop something moving?" or "Was World War II good or bad?"

He gives them no clue where to start, but-crucially-he insists that the school restrict the number of Internet portals in the class to one for every four students. One child in front of a computer learns little; four discussing and debating learn a lot. What happens next is entirely up to the students. All they know is that Dr. Mitra is coming back to be told what they have found.

He arrives with a second question that links the learning more closely to the curriculum, such as: "Who was Isaac Newton?" and then "What's the connection between Newton and stopping things moving?" The kids teach themselves the laws of motion. Of course, the Internet is fallible as a source, but so are teachers and textbooks. For the noncontroversial topics that make up the curriculum, even Wikipedia is pretty good.

In a village in Tamil Nadu called Kalikuppam, Dr. Mitra asked a class of poor Tamil-speaking kids to use the Internet, which they had not yet encountered, to learn biotechnology, which they had never heard of, in English, which they did not speak. Two months later he was astounded at what they had taught themselves.

In 2006, Dr. Mitra moved to England, became a professor of educational technology at Newcastle University, and tested SOLE in schools in a poor urban neighborhood, teaching teachers to be facilitators rather than pedagogues.

On their own, children can get about 30% of the knowledge required to pass exams. To go further, Dr. Mitra supplements SOLE with e-mediators, or the "granny cloud" as he calls it: amateur volunteers who use Skype to help kids learn online.

The experiment is now going global. Schools in Australia, Colombia, England and India are trying SOLE and sharing their experiences of how to improve it. The U.S. has been slow to join, says Dr. Mitra, because Americans tend to view the program as relevant only to the developing world. But schools in Nevada, Maine and San Francisco have recently called on him to explain his ideas.

One of my philosophical passions is bottom-up order. Human beings have a hard time understanding that some of the finest complexity in the world comes about through spontaneous emergence, not top-down diktat. This is true of ecosystems and economies, of genomes and cultures, of embryos and encyclopedias.

Education, though, feels like one of those things that has to be top-down: There has to be a teacher and a taught. But plenty of people educate themselves. Is it possible for everybody to be an autodidact, now that knowledge is so accessible online?

The key issue going forward for natural gas is not managing supply, but creating demand.

The US success in shale gas technology can be replicated in multiple locations world-wide.

Environmental issues surrounding water use, hydro-fracturing, well spacing and disruption to communities are more often the product of fear and myth, not present and future reality.

Natural gas can provide currently viable, scalable, affordable and significant but partial decarbonization of the electric generation sector.

We must be realistic: Other technologies aim for a full decarbonization at some point several decades away.  Is it wise to bet on technology today for 2050?

The greater environmental risks are likely to be those associated with not developing shale resources.

Similarly, the greater economic risks of shale increasingly appear those associated with NOT developing shale resources.

Shale gas has the potential to reduce energy costs during a time when global stimulus is again becoming necessary.

Lower energy costs reach consumers and industry far quicker than tax or regulatory changes can.

Europe in general and the UK in particular risk being marginalized as China and India embrace shale gas potential as other nations deny it.

Green issues are more likely to be raised in Europe not by environmentalists, but by those funded by the nuclear, Coal Carbon Capture and Storage, gas storage and large scale pipeline project industries.

Sir,

Last winter, we were told by scientists that it was `stupid' to take the cold weather as evidence against global warming. Yet this winter you are quite happy to speculate, entirely against the consensus view, that the cold weather is evidence for global warming (`A Cold Warming', Dec 4^th). In support of this fancy, you cite `some' evidence that summer heat `may' induce shifts in atmospheric circulation that `might' encourage seasonal patterns that would `probably' mean more cold winters in Britain. Spare us the astrology, please.

Matt Ridley

Northumberland

The article contains the following paragraph:

Europe's cold winters and the warmth of the planet as a whole might even be linked. There is some evidence that the summer heat stored in the newly ice-free seas north of Siberia may induce shifts in the atmosphere's circulation, when the heat is given up to the air in subsequent autumns and winters. Those shifts might in turn encourage seasonal patterns in which the Arctic is warm and the continents below it cold, as in early 2010. Since the sea-ice area looks likely to go on shrinking, such a link, if indeed it exists, would probably mean more cold winters in Britain and much of Europe.

There is a more serious point at issue here. Without man-made global warming Britain experienced terrible winters like that of 1947 and 1963. If the Economist is right and it can still experience such winters despite (or even because of) global warming, then where exactly is the problem? How are we to distinguish the effect of climate from weather?

Observe the following chart, from Willis Eschenbach, showing the temperature record in Armagh, Northern Ireland. The dark blue line is climate change (with a healthy helping urban heat island effect). The pale blue fuzz is weather.

(picture from Eden's Path)

Steve Landsburg, writing at The Big Questions, takes issue with Paul Krugman's argument that restricting free trade cannot cause a depression:

Paul Krugman writes that  trade does not equal jobs and concludes that trade restrictions cannot even in principle trigger a depression. After all, restricting trade means restricting exports (less jobs!) but it also means restricting imports (more jobs!) so everything washes out.

Well, let's try an extreme example. Suppose I prevent everyone in America from trading with anyone outside their own households. We'd eat only what we could raise in our own gardens, burn only the fuel we could gather from our own backyards, and wear only the clothes we could make for ourselves. In other words, we'd all be living pretty much at the subsistence level. Would you be willing to call that a Depression? I would. Krugman, apparently, would not.

Lansburg is dead right. In my book I argue that prosperity is directly proportional to the degree of specialisation and exchange, or to put it in Adam Smith's words, the `division of labour is limited by the extent of the market'. That is to say, throughout human history, people have moved away from self-sufficiency towards working for each other and grown more prosperous as a result. When you work for each other, you can be more productive because you specialise in tasks at which you are skilled or for which you have labour-saving devices.

Working for yourself means consuming only what you can produce. It makes you a more diversified producer but a more limited consumer. If you had to make your own food, fuel, clothing and shelter, you would have a lot less time to make things like light or entertainment. The key metric is time taken to fulfil a need or a desire.

Here's an example from the blog whence the picture above came, Eden's Path, written by a couple who are trying to be as self-sufficient as possible in Virginia:

We got tired of spending over $1-a-bar for soap several weeks ago, so we started looking around for ways to make soap at home. Most soapmaking was either dangerous - "lye can cause an explosion" - or too time-consuming - "let the soap cure for 30-days." So, we kept looking until we found the perfect solution. Our 3.5-ounce bars of soap now cost us only $0.65/each, take about 30-minutes to make, and do not put us in danger of being blown off the face of the earth. All good reasons to make your own soap.

Hang on. They are taking 30 minutes to save themselves 35 cents per bar. Even if you assume it takes two of them only 30 minutes each to make 24 bars, and that they use as many as two bars a month, they are spending 60 minutes to make a saving of just under eight dollars. That's almost exactly the minimum wage.

Here's a paragraph from my book, The Rational Optimist, on the subject of self-sufficiency:

In 2009, an artist named Thomas Thwaites set out to make his own toaster, of the sort that he could buy from a shop for about £4. He needed only a few raw materials: iron, copper, nickel, plastic and mica (an insulating mineral around which the heating elements are wrapped). But even to get these he found almost impossible. Iron is made from iron ore, which he could probably mine, but how was he to build a sufficiently hot furnace without electric bellows? (He cheated and used a microwave oven.) Plastic is made from oil, which he could not easily drill for himself, let alone refine. And so on. More to the point, the project took months, cost a lot of money and resulted in an inferior product. Yet to buy a £4 toaster would cost him less than an hour's work at the minimum wage. To Thwaites this illustrated his helplessness as a consumer so divorced from self-sufficiency. It also illustrates the magic of specialisation and exchange: thousands of people, none of them motivated by the desire to do Thwaites a favour, have come together to make it possible for him to acquire a toaster for a trivial sum of money. In the same vein, Kelly Cobb of Drexel University set out to make a man's suit entirely from materials produced within 100 miles of her home. It took 20 artisans a total of 500 man-hours to achieve it and even then they had to get 8% of the materials from outside the 100-mile radius. If they worked for another year, they could get it all from within the limit, argued Cobb. To put it plainly, local sourcing multiplied the cost of a cheap suit roughly 100-fold.

However, the evolution of society towards increased specialisation and exchange is not unidirectional. History is littered with examples of people who moved back towards self-sufficiency as they grew less prosperous. Unable to find trading partners to do mutual service with, they had to serve themselves and that made them poorer.

Two examples, both from The Rational Optimist:

The economist Vernon Smith, in his memoirs, recalls how in the Depression his family moved in the 1930s from Wichita, Kansas, to a farm when his father was laid off as a machinist, because 'we could at least grow most of our own food and participate in a subsistence economy.'

And the end of the Roman empire.

As Roman rule disintegrated, at least in the west, money lending at interest stopped and coins ceased to circulate so freely. In the Dark Ages that followed, because free trade became impossible, cities shrank, markets atrophied, merchants disappeared, literacy declined and - crudely speaking - once Goth, Hun and Vandal plundering had run its course, everybody had to go back to being self-sufficient again. Europe de-urbanised. Even Rome and Constantinople fell to a fraction of their former populations. Trade with Egypt and India largely dried up, especially once the Arabs took control of Alexandria, so that not only did oriental imports such as papyrus, spices and silk cease to appear, but those export-oriented plantations in Campania became the plots of subsistence farmers instead. In that sense, the decline of the Roman empire turned consumer traders back into subsistence peasants. The Dark Ages were a massive experiment in the back-to-the-land hippy lifestyle (without the trust fund): you ground your own corn, sheared your own sheep, cured your own leather and cut your own wood. Any pathetic surplus you generated was confiscated to support a monk, or maybe you could occasionally sell something to buy a metal tool off a part-time blacksmith. Otherwise, subsistence replaced specialisation.

What is particularly clever about the book is the way that Worstall makes economic theory so digestible, even delicious. He refutes the dreary cliche so popular among environmentalists that economics just `does not get' the environment (by which they usually mean that they would like to do the equivalent of repeal the laws of gravity and make things to happen even if they make no sense for people: like getting people to give up cheap forms of energy to take up expensive ones). Quite the reverse is true: environmentalists all too often just don't get what economists are trying to tell them.

I especially liked this little section which so neatly eviscerates the Stern Report:

That climate change is a market failure does not, as has already been pointed out, mean that all markets have failed, that all possible variants of markets will fail to deal with this problem, only that the market system as currently extant is failing to deal with this specific problem. Our choice of how to use markets to rectify this comes in one of two flavours: we can either shoehorn the problem into current markets or we can create a new market to deal with this problem.

Shoehorning comes from (as Stern goes to great lengths to point out) the acknowledgement that emissions are an externality. They are an effect of our actions which are not currently included in the market prices which guide our actions. As Marshall pointed out at the turn of the last century and as his successor Pigou went on to solve for, we know what to do with these. We add a tax to the action so that market prices now reflect the true costs of said actions. We've even got a number from Stern as to what that tax should be: $80 per tonne CO2.

We ought to take a little detour here to discuss the validity of that $80 and truth be told, there's not a great deal of validity to it. The Stern Review plays a number of tricks to get to it. The first and most obvious is that all of the calculations are based upon only one of the four families of possible economic (and thus emissions scenarios) that the IPCC itself considers. You don't have to be as cynical as I am (although I prefer "realist" when trying to describe my bleak and total cynicism about the actions of politicians and their hirelings) to guess that he used the very worst of those economic models, the family that produces hugely high emissions by comparison with the others.

No, sorry, let me backtrack a little. He does use another set of emissions: one he made up for the task. One that the IPCC hasn't considered and one which is, yes, you guessed it (see, told you, realism) even worse. So our $80 is based upon as bad as the IPCC thinks it could be and worse: no consideration is given to the idea that it might not be that bad but that's still part of where we get our $80 from.

The second trick is that Stern essentially invents a new way of dealing with discount rates. No, we'll not go there, it's very long and boring but let's just say that his treatment of this issue received a great deal of commentary ("commentary" is the polite way economists describe making the point "You did what? But, but, don't you understand the implications of that? Buffoon!**") from economists who had actually been working within the IPCC structure, economists like Sir Partha Dasgupta and Richard Tol.

A third trick, well, no, not really a trick, rather a gross oversight, comes in the treatment of the technological and capital cycles.

One of the great arguments in economics (it's at the heart of what all those talking heads on the TV screens are shouting about, recession, unemployment, government spending and the rest) is about how quickly things happen. If this bit of the economy over here changes then how long does it take for that bit over there to adjust to it? A Keynesian (or even a New Keynesian, although for slightly different reasons) will think that in a recession then wages won't change, won't change quickly enough at least, which is why we get unemployment. A New Classical (or again, for slightly different reasons, a Real Business Cycle theorist) would say that of course wages will adjust, near instantaneously and thus there cannot be recessions and whatever it is that we're seeing is caused by something else. Entirely. No doubt at all. That however is macroeconomics, as PJ O'Rourke pointed out, the part of the subject where we're reasonably certain that we don't know what we're talking about.

However, microeconomics (the bit where we know a bit is correct at least) covers the same point about how quickly things happen. For example, we know that the short and long term effects of tax changes are different: it takes time for people to change their behaviour. We also know that we've something we can call the technological cycle: how long does it take to get some new whizzy way of doing something into the hands of people who will use it to do whizzy things? Specifically, here, with climate change, we'd like to know how long it takes to get some nice new low carbon technology thought about, developed, tested, manufactured and thus really ready for use. Given that windmills have been around in Europe since at least the 12 th century we can see that it can be a fairly considerable amount of time.

I recently came across the phrase "remembering the future." Rather than some empty poetic paradox, it appeared in an article about a neuroscientific experiment that tested a hypothesis of Karl Friston of University College, London, that the brain is more active when it is surprised.

In the study, volunteers watched patterns of moving dots while having their brains scanned. Occasionally, a dot would appear out of step. Although there was the same number of dots, the visual part of the subjects' brains was more active when the dots broke step. According to Arjen Alink of the Max Planck Institute in Frankfurt, Germany, who did the experiment, the brains were predicting what would happen next and having to work harder when their predictions failed. They were "remembering the future."

There is a growing conviction within neuroscience that one of the human mind's chief preoccupations is prediction. Jeff Hawkins, the founder of Palm Computing who is now a full-time neuroscientist, argued in his 2004 book "On Intelligence"that the mind does this by detecting a familiar pattern in its input, then anticipating from past experience what usually follows. The more unexpected something is, the more conscious we are of it.

This explains a lot about awareness. When I push my foot down on the brake pedal, I expect to feel deceleration. If I do, I am barely conscious of the fact: My mind continues to concentrate on the radio or my conversation with my passenger. If I don't, I am immediately so aware of the car skidding on the ice or the brakes failing that my mind is fully occupied with the failed prediction.

The big brains of human beings undoubtedly lead them to predict patterns further ahead than other animals. My dog is quite capable of expecting to be taken for a walk or given her dinner at certain times of the day. But she is not capable, as I am, of expecting cold weather in winter or predicting the need to pack a suitcase before a trip. Still, she probably has a longer view of the future than a guinea pig, which in turn sees further ahead than a frog.

Some birds stand out as exceptionally good at "mental time travel." The psychologist Nicky Clayton observed that western scrub jays steal food left behind by lunching students at the University of California at Davis. The jays hid the food by digging it into the ground. Sometimes they came back later and moved the food-but only if they had been observed by other jays when hiding the food in the first place. Dr. Clayton has since shown in her lab at Cambridge University that they do this to foil thieves, and that scrub jays are uniquely forward-thinking in this respect, even compared with other food-caching species of bird.

Dr. Clayton's other experiments with children reveal that this mental time travel becomes possible for human beings around the age of five. As adults, we inhabit longer futures than children, and longer pasts, too.

Daniel Schacter of Harvard University has made the remarkable discovery that the same parts of the mind hold both our episodic memories and our imagined futures. That is to say, if asked to imagine some specific future event, people activate the very same regions of the brain as they do when asked to recall some particular past event. Indeed, people who suffer strokes that affect these regions lose not just the ability to remember their own lives but the ability to imagine future possibilities as well.

Dr. Schacter concludes, much like Dr. Hawkins and Dr. Friston, that "a crucial function of the brain is to use stored information to imagine, simulate and predict possible future events." Through technology like writing and printing, the longer we extend the past, the longer our view of the future becomes. But that is a subject for another column.

Update: the photo above shows a wind turbine's parts blocking a road in Wales.

Two hundred years ago, Britain discovered how to make energy cheaper and cheaper, which caused a rush to mechanisation, which raised living standards all around the world by making it easier to fulfil people's needs and wants through the amplification of work by cheap and reliable energy turning ingenious machinery. We call it the industrial revolution.

Today Britain officially announced that it would single-handedly reverse this revolution by deliberately trying to make energy more expensive. It intends to do this by adopting sources of power that are irregular, unreliable, capital-intensive, unsightly, bird-killing, bat-killing, steel-rich, concrete-hungry, neodymium-demanding, dependent on Chinese imports and thirteenth century in concept. It intends to ask the poorest in society to pay hefty subsidies through their electricity bills to the richest. And it intends to do all this unilaterally so that we export jobs to other countries. It is mad.

Here is James Delingpole:

In other words, what Chris Huhne and David Cameron are asking British business to accept is a swingeing impost which fines companies at £27 a tonne for an (almost inescapable) by-product for which our global competitors are charged nothing at all. I don't think any of us have much objection to Chris Huhne's insatiable urge to be the first lemming over the cliff. What is of concern is the fact that currently he has been granted the power to drag us all over with him.

Every week, every day almost, I post in these pages about the economic and ecological disaster which awaits Britain if it goes ahead with Huhne's and Cameron's insane proposals to "decarbonise" the British economy at a cost conservatively estimated at £18 billion a year. What depresses me almost as much as the sheer bloody uselessness of the Coalition is the bloody uselessness of my colleagues in the Fourth Estate (even the notionally "conservative" or free market ones) in opposing its wilder idiocies.

``No longer are exposures to dangerous chemicals occupational alone; they have entered the environment of everyone-even of children as yet unborn. It is hardly surprising, therefore, that we are now aware of an alarming increase in malignant disease.

The increase itself is no mere matter of subjective impressions. The monthly report of the Office of Vital Statistics for July 1959 states that malignant growths, including those of the lymphatic and blood-forming tissues, accounted for 15 per cent of the deaths in 1958 compared with only 4 per cent in 1900. Judging by the present incidence of the disease, the American Cancer Society estimates that 45,000,000 Americans now living will eventually develop cancer. This means that malignant disease will strike two out of three families. The situation with respect to children is even more deeply disturbing. A quarter century ago, cancer in children was considered a medical rarity. Today, more American school children die of cancer than from any other disease. So serious has this situation become that Boston has established the first hospital in the United States devoted exclusively to the treatment of children with cancer. Twelve per cent of all deaths in children between the ages of one and fourteen are caused by cancer. Large numbers of malignant tumors are discovered clinically in children under the age of five, but it is an even grimmer fact that significant numbers of such growths are present at or before birth. Dr. W. C. Hueper of the National Cancer Institute, a foremost authority on environmental cancer, has suggested that congenital cancers and cancers in infants may be related to the action of cancer-producing agents to which the mother has been exposed during pregnancy and which penetrate the placenta to act on the rapidly developing fetal tissues.''

Carson was wrong about this. Not only has DDT proved not to be a carcinogen, but the cancer epidemic caused by exposure of the general public to chemicals has wholly failed to materialise. Study after study has found that there is no increase in cancer incidence or death in the general population, when corrected for age, to be explained by man-made chemicals. Those, like Paul Ehrlich, who confidently predicted that the lifespan of Americans would fall to 42 years by the end of the twentieth century thanks to such cancer epidemics, were proved badly wrong.

Here are the charts of cancer deaths for men and women, adjusted for age, in the United States since the 1930s.

The one that stands out, of course, is lung cancer. The rapid increase in lung cancer (boosted surely changing diagnosis in the early years) was caused by the increase in smoking, of course. Almost nobody now challenges that. But they did once. Indeed, one of the most vociferous opponents of the theory that smoking causes lung cancer was none other than Carson's mentor, William Hueper.

So obsessed was Hueper with his notion that pesticides and other synthetic chemicals were causing an epidemic of cancer and that industry was covering this up, that he bitterly opposed the suggestion that smoking take any blame - as an industry plot.

Here he is writing a paper called Lung Cancers and their Causes in 1955 in CA, a cancer journal for clinicians  http://caonline.amcancersoc.org/cgi/content/abstract/5/3/95:

1. The total epidemiological, clinical, pathological, and experimentalevidence on hand clearly indicates that not a single but severalif not numerous industrial or industry-related atmospheric pollutantsare to a great part responsible for the causation of lung cancer.

2.While the available data do not permit any definite statementas to the relative importance of the various recognized respiratorycarcinogens in the production of lung cancers in the generalpopulation, they nevertheless unmistakingly suggest that cigarettesmoking is not a major factor in the causation of lung cancernor had it a predominant role in the remarkable increase ofthese tumors during recent decades.

3. In view of the fact thatnot only a great deal of the existing circumstantial epidemiologicalevidence but also pratically the entire factual and conclusiveevidence available on exogenous respiratory carcinogens areeither of occupational origin or point to industry-related factors,it would be most unwise at this time to base future preventivemeasures of lung-cancer hazards mainly on the cigarette theoryand to concentrate the immediate epidemiological and experimentalefforts on this evidently overpropagandized and insufficientlydocumented concept.

When environmentalists want to attack a sceptic these days, they quite frequently accuse him or her of being the kind of person who would have defended the tobacco lobby - in some cases with justification. So it is ironic to find that possibly the most iconic and original text of the entire environmental movement, Silent Spring, was built on the work of a fervent tobacco defender. Hueper is quoted frequently throughout Carson's book.

By the way, in my book I say that Rachel Carson `expected DDT "to cause practically 100 per cent of the human population to be wiped out from a cancer epidemic in one generation"'. This is inaccurate: I slipped up. I relied on an article in a magazine called Front Page in July 2003 for this quotation, and unusually I did not check it with Carson's original text. Alerted by a reader, Ed Darrell (thanks!) I have now checked Carson's Silent Spring, and while Carson strongly implies that she does indeed expect a major mortality from cancer caused by DDT, what she actually wrote is the following:

In the springof 1961 an epidemic of liver cancer appeared among rainbow trout in many federal, state, and private hatcheries. Trout in both eastern and western parts of the United States were affected; in some areas practically 100 per cent of the trout over three years of age developed cancer. ...The story of the trout is important for many reasons, but chiefly as an example of what can happen when a potent carcinogen is introduced into the environment of any species. Dr. Hueper has described this epidemic as a serious warning that greatly increased attention must be given to controlling the number and variety of environmental carcinogens. 'If such preventive measures are not taken,' says Dr. Hueper, 'the stage will be set at a progressive rate for the future occurrence of a similar disaster to the human population.'

My book criticises Carson and her followers for their exaggerated pessimism which led to the phasing out of DDT as an anti-mosquito weapon and hence led directly to the resurgence of malaria. This is a story that has been well told in many places and deserves to be better known. But I find many of DDT's defenders then go on to make a claim that I do not believe is correct, namely that DDT had no impact on birds, and that the story that it led to the thinning of eggshells in birds at the end of long food chains, such as falcons and pelicans (and also damaged the reproduction of predatory mammals such as otters), is false. I simply do not accept that. The evidence of bioaccumulation in fat, of eggshell thinning and of DDT's role in the decline of raptors and other predatory birds in the 1960s seems to me fairly strong, though not overhwelming. The ending of indiscriminate and widespread spraying of DDT is probably a good thing.

It is, fortunately, very easy to use DDT against malarial mosquitoes without poisoning birds. The solution is to use it sparingly on the inside walls of houses, where anopheline mosquitoes rest during the day. This targets the pest while not allowing the pesticide to contaminate the food chain in nearby ecosystems. The best of both worlds.

Don't look for the soul in the language of DNA

Back in the genomic bronze age-the 1990s-scientists used to think that there would prove to be lots of unique human genes found in no other animal. They assumed that different species would have many different genes. One of the big shocks of sequencing genomes was not just the humiliating news that human beings have the same number of genes as a mouse, but that we have the same genes, give or take a handful.

This humiliation deepened recently when David Knowles and Aoife McLysaght at Trinity College, Dublin, tracked down, at last, some uniquely human genes: just three of them. They estimate that there are, altogether, probably no more than 18 of this wholly unique kind-out of 22,568 genes in total. Over the span of our history, human beings seem to have acquired a brand-new gene only every third of a million years.

The three that Drs. Knowles and McLysaght identified lie in stretches of DNA that are gobbledegook in chimpanzees, gorillas, gibbons and macaques, so the chances are they have sprung to life as protein-coding sequences in human beings uniquely. (A gene is the digital recipe for making a protein molecule.)

The functions of these three genes are not yet known (since they don't exist in mice, experiments are tricky), though one seems to be slightly more active in people with a form of leukemia. They are small and simple genes, however-unlikely candidates to hold the recipe for the human soul.

This might seem to leave a small hook upon which philosophers could hang the uniqueness of the human race. But we have long known that our uniqueness lies in the order and combination of our genes, not in the ingredients themselves. DNA is not only like a language; it is a language, a linear sequence of recombinable digital characters of infinite variety.

There are close parallels between DNA and a language like English. Just as evolution uses the same 22,000 genes in a different order to make a rhinoceros or a rabbit, so Shakespeare used many of the same 18,000 words in each of his plays. The 10 most common words in "Othello" and "King Lear" are the same (I, and, the, to, you, of, my, that, a, in), yet the plays are very different. The English language, like the human genome, contains very few brand new words that were invented recently from scratch.

Most new English words arise by different means: by borrowing from foreign languages (Schadenfreude, pajama); by recombining existing words (blogosphere, download); or by the addition of second meanings to existing words (green, mouse).

All of these habits are common in the genome, too. Lateral gene transfer brings genes from one species into another, especially among bacteria (less often among mammals like us). This is just like borrowing a foreign word. Genes recombine by fusing in whole or in part, by a process known as exon shuffling (exons are the separate stretches of code that are used to make one protein in split genes). This is just like recombining existing words. And genes often duplicate themselves and then diverge into different functions, just as old words acquire new meanings.

About 800 million years ago, a gene for a simple pigment protein enabling worm-like creatures to see was duplicated, and the daughter genes diverged to give the different proteins used in the rods and cones of the eye. About 500 million years ago, in a lamprey-like fish, the gene used in cones duplicated and diverged again to give us blue versus yellow color vision. About 30 million years ago, in a tree-climbing primate, the yellow gene duplicated and diverged again to give us green-red color vision.

Genes also die out, just as words do. When they are still recognizable but no longer in use, they are called pseudogenes. The word "theatrophone" is a forgotten linguistic pseudogene, and the word "minidisc" is becoming one. The words "trebuchet" and "cenotaph" are examples of extinct words that sprang back to life-something that pseudogenes sometimes do as well.

I mean it. 2011 will see horrible things, no doubt, but it will also see a continuing incremental reduction in poverty, hunger, illness and suffering, plus a continuing incremental rise in most measures of human and planetary wellbeing.

Here's a fine blast of optimism from John Tierney in the New York Times. He took a bet with a peak-oiler and won hands down.

It's true that the real price of oil is slightly higher now than it was in 2005, and it's always possible that oil prices will spike again in the future. But the overall energy situation today looks a lot like a Cornucopian feast, as my colleagues  Matt Wald and  Cliff Krauss have recently reported. Giant new oil fields have been discovered off the coasts of Africa and Brazil. The new oil sands projects in Canada now supply more oil to the United States than Saudi Arabia does. Oil production in the United States increased last year, and the Department of Energy projects further increases over the next two decades.

The really good news is the discovery of vast quantities of natural gas. It's now selling for less than half of what it was five years ago. There's so much available that the Energy Department is predicting low prices for gas and electricity for the next quarter-century. Lobbyists for wind farms, once again, have been telling Washington that the "sustainable energy" industry can't sustain itself without further subsidies.

As gas replaces dirtier fossil fuels, the rise in greenhouse gas emissions will be tempered, according to the Department of Energy. It projects that no new coal power plants will be built, and that the level of carbon dioxide emissions in the United States will remain below the rate of 2005 for the next 15 years even if no new restrictions are imposed.

Maybe something unexpected will change these happy trends, but for now I'd say that Julian Simon's advice remains as good as ever. You can always make news with doomsday predictions, but you can usually make money betting against them.

I give some reasons for optimism in a Times article last week. Here is a slightly expanded version of it.

With one tenth - well, 11% -- of the twenty-first century now consigned to history, what is the verdict so far? A terrorist mass murder, two long wars, a financial crisis and a deep recession: not great. So perhaps it would surprise you to learn that, according to respectively Steven Pinker of Harvard University and Xavier Sala-i-Martin of Columbia University, the last decade saw the lowest number of global deaths in war since records began in 1945 and the fastest ever reduction in global income inequality.

Britons, who have spent most of this century at war, and the last two years getting poorer, may find these global numbers cold comfort. But they are actually good news for us too. The fact that the world economy grew by more than 5% in 2010 (nearly ten times as fast as it shrank in 2009) means more customers for our exports and more investment elsewhere in things that can improve our lives too - like cancer cures or self-clearing runways.

According to the IMF, away from Europe and North America, the world was booming this year. Asia has grown by 7.9%, South America by 6.3%, Africa by 5% and the Middle-east and North Africa by 4.1%. China and India, with 40% of the world's population, achieved roughly 10% growth between them. Moreover, this boom, because it is happening in poor countries, is rapidly reducing both poverty and inequality.

Despite the Great Recession, the per capita GDP of the average human being - that is to say, the value of goods and services that she consumes in a year - is now just over $11,000, up from about $8,500 (in today's dollars) at the start of the century. If it continues to increase at this rate of just under 3% a year - as it has more than done for 60 years - then by the year 2050 the average citizen of Earth will be earning and spending over $30,000 a year in today's money, roughly the same as the average American spends today. By 2100 she will be spending nearly $150,000 a year, or five times what an American now consumes.

This is almost unimaginable. Try to get your heads round the prospect of Africans and Afghans having the disposable income of today's Americans within the lifetime of your own children, let alone grandchildren. If it seems fanciful, consider this. If my great grandfather had made a similar forecast in 1910, based on the then growth rate of the world economy, then even assuming he would not have predicted two world wars and a Great Depression, he would still have hugely underestimated the average income of today.

What is growth? It means fulfilling more needs and more wants with a smaller amount of work. A kilowatt-hour of electricity cost an hour of work in 1900 for somebody on the average wage; it costs five minutes of work today.

The economic growth of the past decade took a century to achieve in 1810 and took a millennium to achieve in 810. That acceleration shows no signs of stopping, indeed it may be about to redouble. The root cause of economic growth is the mixing of ideas: ideas on how to recombine the atoms and electrons of the world in such a way as to supply people's needs and wants more efficiently. Bring down barriers to the mixing of ideas (barriers in trade, energy, communication and education) and you will cause faster growth whether you want to or not. Nothing has brought down barriers to the mixing of ideas faster than the internet. Today a man in Shanghai and a woman in San Francisco can spark each other's thoughts in seconds, where two decades ago they needed books or aeroplanes to have such mental sex.

Economic growth has a strange and telling feature. While it jumps up and down in individual countries, in the world as a whole it shows an inexorable steadiness. Suppress it in one place and it surges elsewhere. Just as the mandarins who served the Ming emperors once sent prosperity into European exile, by erecting barriers to enterprise, so the Eurocrats who serve Emperor Herman van Rompuy are now returning the favour.

Another symptom of this inexorability is simultaneous discovery. As Kevin Kelly reveals in his remarkable book What Technology Wants, every invention is plagued with disputes between people who perfected rival versions of it at the same moment: from telephones to lightbulbs, from natural selection to Neptune, from vaccines to transistors -synchronous discovery is the rule rather than the exception. That is because each innovation makes the next one `ripe'. And since it is these inventions that raise living standards, the inevitability of discovery means inevitable economic growth.

What is more, this process generates virtue. The essence of virtue is co-operation: pro-social rather than anti-social behaviour. Study after study confirms that immersing people in commerce makes them nicer: le doux commerce, Montesquieu called it. Growth comes about through people working for each other. Self sufficiency is poverty; prosperity is mutual exchange and specialisation. The more you specialise in doing one thing for strangers and they each specialise in doing one thing for you, the better your productivity and the greater your standard of living. Millions of people you will never meet contributed to making for you each of the objects you use in your everyday life. Far from being a selfish creed, economic growth spreads collaboration.

Moreover, with growth come other non-material benefits. As people get richer so they demand that more money and attention be paid to what were once luxuries like clean water, clean air, clean energy and biodiversity. So it is not just child mortality and family size that fall rapidly with wealth; pollution and habitat destruction come tumbling down once incomes pass a level of about $8,000 a head. More and more countries are passing that threshold right now. Watch