A very thin reed
Tamino has an interesting post on Arctic and Antarctic ice extent. Now if you stare at the stuff long enough you realize that the maximum is pretty much always the same
but after a bit of thought, you realize that the Arctic is a closed ocean and it pretty much freezes completely over each year (PS the above only goes to 2000 and does not show the 2000 - 2007 decline. Tamino has the more recent information). Still, this is not completely the case, and analysis shows that even in the winter the ice area is declining.
we can learn even more by looking at maps of the maximum ice concentration from the National Sea Ice Data Center. The map on the left is from Feb 1979 and the one on the right from Feb 2007.
The major differences are in the areas north of the Norway/Russian border. But when we look at the minimum extent from 2007 we see that it is the area between Alaska and Siberia that is relatively clear of ice.
So, we still need to decide whether our bet with Belette is in carrots or in pounds. Hmm, maybe we are looking at the wrong thing. During the autumn and winter the Arctic freezes over, but HOW THICK IS THE ICE. The thicker the ice, the more heat needed to melt the stuff in the summer. The thinner the less.
There are not very many measurements of ice thickness trends for obvious reasons. The best come from Rothrock at the University of Washington who analyzed data from nuclear submarine cruises (Al Gore played a key role in getting these released). Here is what he came up with.
What is a bunny to do? Well we will chew a few carrots and keep a close watch on how rapid the freeze is and try and figure out how deep.
Tuesday, October 09, 2007
A very thin reed