Climate Feedback

Eyjafjallajökull eruption: good news for the climate?

Olive Heffernan

DSCF9275.jpgI’m due to travel to Japan this Friday for a conference on Climate Change Effects on Fish and Fisheries. If I get there, I’ll be providing regular updates from the conference here on Climate Feedback. But that’s beginning to look like a big ‘if’. The volcanic ash cloud from Eyjafjallajökull is still keeping planes grounded across the UK and could do for several days to come.

That’s bad news for a lot of people, but could it be good news for the climate?

Over on Treehugger, Matthew McDermott writes:

Resurgence magazine has posted on their Facebook page an interesting stat attributed to the Plane Stupid: "200,000 tonnes per a day of CO2 emissions have been prevented as a result of cancelled flights – that’s the same as 100,000 households would create in a whole year”. How that figure was derived isn’t entirely clear in terms of what assumptions were made, is that just passenger flights, et cetera.

There’s also the question of how the absence of contrails – or condensation clouds – from commercial airplanes will affect the climate in the short term. Remember that post 9/11 contrail study, which supposedly showed that the average daily temperature over the continental US suddenly widened in the 3 days after the September 11 terrorist attacks, when all commercial air traffic was banned from American skies? Its main conclusion – that daily highs and lows in temperature were more extreme in the absence of contrails – has since been refuted, but the flight ban over Europe should provide another opportunity to test the hypothesis.

And then, of course, there’s the ash from Eyjafjallajökull itself. The eruption of Mount Pinatubo in the Philippines in 1991 cooled global temperatures by about half a degree over the following months, which has led some to propose pumping sulphate aerosols into the atmosphere as a means of artificially cooling the climate. Katharine Sanderson writes on The Great Beyond:

So will the ash from have a lasting effect on our climate? Probably not according to Alan Robock, a meteorologist from Rutgers University, New Brunswick, US. “So far, the emissions have been so small, that I expect no climate impacts,” he says. On April 14, there was 0.004 megatons of sulphur dioxide, as compared to 20 megatons for Mount Pinatubo in 1991, and it was emitted into the troposphere, where its lifetime is only a week or so, as opposed to 1-2 years for the stratosphere for Pinatubo. The ash will also fall out quickly, so I expect no climate impact, unless the eruption gets much stronger.

Also on The Great Beyond, Daniel Cressey offers some assistance in pronouncing Eyjafjallajökull.

Image details: Volcanic ash, from the Eyjafjallajökull volcano in Iceland, is currently shrouding the whole of Northern Europe. Flying at around 30,000 feet, this Icelandair flight FI450 skirted the edge of the vast grey ash cloud (to the right of the jet engine) offering a rare glimpse of the cause of the air-travel disruption in Europe. Photo by Tom Bradwell of the British Geological Survey.


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