NSIDC - Arctic Melt Season Ends, Likely With Lowest Volume Ever - Multi-Year Decline Intensifies

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Last week, National Snow and Ice Data Center (NSIDC) director Mark Serreze said, “Every bit of evidence we have says the ice is thinning.” Monday, NSIDC scientist Julienne Stroeve sent me this figure from a forthcoming article using data provided by J. Maslanik and C. Fowler (click to enlarge):



This is the end-of-winter sea ice extent in the Arctic Basin, broken down by age. Stroeve explains:

"This figure would support thinning of the icepack over the last couple of decades since older ice tends to be thicker than younger ice. You can see in this figure how little of the really old, and thick ice there is left in the Arctic Basin."

In fact, the figure shows ice 5 years or older dropping from 800,000 sq-km in 2008 to 400,000 in 2009 to only 320,000 sq-km. Spring 2010 also saw a record low in the amount of ice 4 years or older. Now you can see that we just about hit the same Arctic sea ice area that we did in 2008:



Given that the ice is almost certainly thinner now than in 2008, we are very likely to have witnessed a lower total ice volume. Remember, 2008 had substantially less ice volume than 2007, even though it had more area. Last year, some of the leading cryoscientists at JPL, the Polar Science Center at the University of Washington, and NASA published a major peer-reviewed article, “Thinning and volume loss of the Arctic Ocean sea ice cover: 2003–2008” (subs. req’d).

EDIT

http://climateprogress.org/2010/09/14/exclusive-scientists-track-sharp-drop-in-oldest-thickest-arctic-sea-ice/