12/12/2009

Arctic Sea Ice since 2007

With those explaining that Climategate means nothing pointing to the Arctic Ice sheet, I thought that I would look up some numbers. According to the World Meteorological Organization, Arctic sea ice has increased by 19 percent since its minimum in 2007, though they don't make it very easy to see this in the way that they report the data. 2009 was indeed still 27.4 percent below the 1979 to 2000 average of 7.03 million square kilometers, but the gap has gotten much smaller than the 39.2 percent in 2007.

Year . . . . Average Minimum Extent (million square kilometers)
2007 . . . . 4.28
2008 . . . . 4.67
2009 . . . . 5.10

Al Gore claimed during the Copenhagen Climate Summit that "These figures are fresh. This is the volume metric measure of the ice and some of the models suggest to Dr Maslowski that there is a 75 per cent chance that the entire north polar icea cap, during the summer months, could be completely ice-free within five to seven years." Gore apparently didn't have the last two years of data with his "fresh" figures. For the AP version of the story, which doesn't question his claims at all, see here.

The claim was simply obtained by extrapolating the drop from 2006 to 2007 and assuming that the rate of drop would continue. The fact that the amount of ice increased after that would presumably bring some caution to the discussion.

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3 Comments:

Blogger Jerry Lingle said...

Two measurements are important, extent and thickness of the ice. Both have to be considered - ice caps are not as thick...

12/13/2009 11:49 AM  
Blogger therandomgeofer said...

Can you elaborate, Jerry?

1/04/2010 8:36 AM  
Blogger ACE said...

are you guys insane? Please look at all the data before making such sweeping remarks. It's like looking outside at night and claiming the sun has extinguished because it is no longer there!


http://arctic.atmos.uiuc.edu/cryosphere/

3/01/2010 2:55 PM  

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