A pair of new studies shows that winter sea ice in the Arctic has shrunk dramatically in the past two years and that perennial ice in particular is disappearing. Two types of sea ice cover the Arctic Ocean: thick perennial ice that resists thaw year-round and thinner seasonal ice that melts during the summer and freezes again in the winter. Both types are experiencing decline, according to analyses of microwave satellite data. Researchers led by Joey Comiso of NASA’s Goddard Space Flight Center in Greenbelt, Maryland found that the amount of ice covering the Arctic has declined by 6 percent over each of the last two winters, compared to a loss of merely 1.5 percent per decade since 1979. Comiso’s team did not distinguish between perennial and seasonal ice, but he told LiveScience most of the loss was likely seasonal ice. ‘This amount of Arctic sea ice reduction the past two consecutive winters has not taken place before during the 27 years satellite data has been available,’ Comiso said. The researchers said that warming temperatures and a shorter winter-ice season are likely to blame. ‘In the past, sea-ice reduction in winter was significantly lower […]