CryoSat-2 observes Arctic sea ice volume recovery, after anomalously low melting in summer 2013

Abstract:

Despite a well-documented ~40% decline in summer Arctic sea ice extent since the late 1970’s, it has been difficult to estimate trends in sea ice volume because thickness observations have been spatially incomplete and temporally sporadic. While numerical models suggest that the decline in extent has been accompanied by a reduction in volume, there is considerable disagreement over the rate at which this has occurred. We present the first complete assessment of trends in northern hemisphere sea ice thickness and volume using 4 years of measurements from CryoSat-2. Between autumn 2010 and spring 2013, there was a 14% and 5% reduction in autumn and spring Arctic sea ice volume, respectively, in keeping with the long-term decline in extent. However, since then there has been a marked 41% and 9% recovery in autumn and spring sea ice volume, respectively, more than offsetting losses of the previous three years. The recovery was driven by the retention of thick ice around north Greenland and Canada during summer 2013 which, in turn, was associated with a 6% drop in the number of days on which melting occurred – climatic conditions more typical of the early 1990’s. Such a sharp increase in volume after just one cool summer indicates that the Arctic sea ice pack may be more resilient than has been previously considered.