No going back for the Arctic

(No emissions from this one for a while)

Professor Jean-Claude Gascard from the Université Pierre et Marie Curie in Paris, heads the EU’s Damocles project, identifying the challenges from climate change. He gave a very sobering summary of the state of the Arctic sea ice and confirmed there is virtually no chance of reversing the current warming trend. Only several extremely severe winters could do that, and the scientific community is not expecting that.
Scientists tend to be reluctant to come out with anything they can’t prove, and Prof. Gascard summed up the main elements behind this conviction. Sea ice extent, depths, age and drift are key factors, as well as the air temperature and the number of “freezing degree days”.
By 2002 the ice was at a minimum based on some 50 years of observation. In 2005, there was no “replenishment” of older, multi-year ice exiting the Arctic ocean. This, Prof. Gascard describes as a “tipping point”.
The ice thickness has decreased over a wide area from more than 3 metres 20 or 30 years ago to around 1.5 metres. I remember my trip out on the sea ice in Barrow, Alaska, with Dr. Chris Petrich and the Climate Change College “ambassadors”. I can hear Erika Naga reading out the measurement “1 metre 40”, and the Inupiat telling us how it used to be much thicker.
The ice is melted in various ways: through warmer water from the Atlantic and Pacific underneath, heat from storms and increased radiation from above.
2007 of course was the year that really made everybody wake up. When the Alfred Wegener Institute’s Polarstern went out to set up ice platforms, there was no ice in their target area. The Tara, which has been frozen in and drifting with the ice to compare ice drift with the “Fram” expedition has been drifting three times faster than her predecessor. And the sea ice reached its minimum. 2008 saw almost the same negative record.
Sea ice reflects much more heat back into the atmosphere than water, (albedo effect) which is much darker and absorbs it, exacerbating the warming, in what’s called a “feedback loop”. Again, I was reminded of our trip on the Chukchi Sea with Chris Petrich from the University of Fairbanks, Alaska, who is collecting data on this to be put into global models.
And the number of “freezing degree days” has dropped massively in the last few years.
Professor Gascard’s summary of all this is available online on the Arctic Frontiers site.

And if you have the time and the inclination, have a(nother?) listen to the feature on my trip onto the sea ice with the Climate Change College.

Tromsö today (the days are getting lighter):