Tuesday, August 25, 2015
Tuesday, August 25, 2015
Sunday, August 16, 2015
Welcome to Matt Ridley's Blog
Matt Ridley is the author of provocative books on evolution, genetics and society. His books have sold over a million copies, been translated into thirty languages, and have won several awards.

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No contrails

Iceland's volcanic cloud keeps the sky clear of planes: will that cause more nocturnal cooling?

The sky's bright blue right now, which is weird because I am looking up through a 5,000-metre thick plume of volcanic ash from Iceland. This has stopped all flights in the UK air space and much of northern Europe.

(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


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?