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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

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?

 

By Matt Ridley | Tagged:  rational-optimist