Thinning ice probably explains record low Arctic sea ice coverage | Carbon Brief
Sea ice extent has undergone a dramatic decline this year, but it doesn't necessarily follow that the volume of sea ice has declined dramatically.2010: RealClimate: An icy retreat
...Axel Schweiger, principal oceanographer at the Polar Science Center told us:"With respect to ice volume from PIOMAS for this summer (and we are not finished), the change from 2011 to 2012 looks actually much less dramatic than the ice extent change and rather in line with previous year to year losses."
However, in March temperatures suddenly dropped for a couple of weeks, in particular in parts of the Barents Sea and in parts of the Beaufort Sea. This in turn lead to the formation of a thin ice cover in these regions, which caused a marked increase in observed sea-ice extent. For the measurement of this extent, it doesn’t matter at all how thick the ice is: any ice, however thin, contributes to sea-ice extent. Therefore, only considering a possible “recovery” of just the extent of Arctic sea ice always remains somewhat superficial, since sea-ice extent contains no information on the thickness of the ice. A much more useful measure for the state of Arctic sea ice is therefore the total sea-ice volume.