Increases in Arctic sea ice volume in autumn 2013 have offset losses of sea ice volume between 2010 and 2012, according to a study published online in Nature Geoscience. The increase in volume followed an unusually cool summer in 2013 and may indicate that Arctic sea ice is more resilient than previously thought.
Satellites have shown that Arctic sea ice extent has declined by about 40% since the late 1970s; however, measuring the extent of Arctic sea ice using satellites is easier than measuring thickness, which is required to calculate volume. In addition, a decline in ice extent is not necessarily indicative of a proportionate decrease in ice volume.
Using data from the European Space Agency’s CryoSat-2 mission, Rachel Tilling and colleagues assessed changes in Northern hemisphere sea ice thickness and volume from 2010 to 2014. The authors detect significant variation in Arctic sea ice volume in autumn, with a decrease by 14% between 2010 and 2012, but substantial increases thereafter. Specifically, total autumn sea ice volume increased by 41% in 2013 and remained higher than the five-year average up to autumn 2014. They conclude that the unusually cool summer of 2013 - with temperatures comparable to the late 1990s - played a key role in the autumn ice volume increase by limiting the melting of thick sea ice northwest of Greenland, but they also note that future warm summers are likely to lead to more sea ice melt.