[Update: I've clarified how the two years of data depicted in the animation above help confirm that the volume of Arctic sea ice has decreased dramatically in 10 years.]
Just in today from British researchers: In only a decade, the volume of Arctic sea ice has declined by a bit more than a third in autumn, and by 9 percent in winter.
The volume of sea ice is different from its aerial extent, meaning how much territory it covers, which I discussed in my earlier post today about the Polar Paradox.
The animation above does not chart the volume of sea ice over the full 10-year period. The red dots chart seasonal changes to the volume of ice, based on observations by the European Space Agency’s CryoSat-2 satellite covering 2011 and 2012. But these data do confirm that in both autumn and winter of both years, ice volume was significantly lower than it averaged between 2003 and 2008.
These findings are consistent with simulations by the Pan-Arctic Ice-Ocean Modelling and Assimilation System (PIOMAS), which are shown with the solid white line in the animation. (To my eye, the PIOMAS model shows somewhat less ice decline that what has actually been observed.)
The background shows how the extent of Arctic sea ice has changed seasonally over the same two-year period. And as with ice volume, over the longer term, less and less of the Arctic Ocean and surrounding seas have been ice covered. With some ups and downs due to natural variability, the extent of Arctic sea ice in September, when it typically bottoms out for the season, has been declining since the advent of satellite recordsin 1979.
“The data reveal that thick sea ice has disappeared from a region to the north of Greenland, the Canadian Archipelago, and to the northeast of Svalbard,” says Katharine Giles, of the Center for Polar Observation and Modeling at University College London, and a member of the scientific team. She was quoted in an American Geophysical Union press release.
The AGU has accepted a paper about the findings, and has published the results online today.