( CNN ) Although much of the United States has been shivering this winter , there 's been another worrying sign of warming temperatures farther north . The cap of sea ice that spreads across the Arctic Ocean in winter appears to have been the smallest on record this year , according to NASA . Not only was this year 's maximum extent , reached on February 25 , the smallest on the satellite record , it 's also one of the earliest . Barring a late spurt of ice growth -- possible but unlikely , according to a NASA news release -- this sets a new precedent . The analysis is based on data from the NASA-supported National Snow and Ice Data Center ( NSIDC ) at the University of Colorado , Boulder . Arctic sea ice , frozen seawater floating on top of the Arctic Ocean and its neighboring seas , is in a state of constant flux . It increases its area in winter , usually peaking between late February and early April , and then shrinks in the warmth of spring and summer to reach its lowest extent in September . If this year 's maximum extent , totaling 5.61 million square miles , was reached on February 25 , it was reached 15 days earlier than the 1981 to 2010 average date of March 12 , according to NSIDC . Only once before did the peak come earlier , by just one day in 1996 . A peak of 5.61 million square miles is about 50,000 square miles below the previous lowest peak wintertime extent , reached in 2011 , according to NSIDC . Scientists have been using satellite data to track changes in Arctic sea ice , a vital habitat for birds and marine mammals such as polar bears , seals and walruses , for over three decades . According to the National Oceanic and Atmospheric Administration , Ted Scambos , NSIDC lead scientist , puts the potentially record low maximum sea ice extent this year down to low ice extent in the Pacific and a late drop in ice extent in the Barents Sea . Strong southerly winds in early March also played a role , according to NOAA . Only the Baffin Bay area and the waters around Newfoundland had more ice than normal this winter , it said . Scientists say it does n't necessarily follow that a low maximum winter extent will mean a record amount of shrinkage in sea ice over the summer , however . While the winter sea ice extent was low in 2006 and 2011 , neither of those years saw an unusually low summer minimum , NOAA said . `` The winter maximum gives you a head start , but the minimum is so much more dependent on what happens in the summer that it seems to wash out anything that happens in the winter , '' Walt Meier , a sea ice scientist at NASA 's Goddard Space Flight Center in Greenbelt , Maryland , is quoted as saying by NASA . `` If the summer is cool , the melt rate will slow down . And the opposite is true , too : even if you start from a fairly high point , warm summer conditions make ice melt fast . `` This was highlighted by 2012 , when we had one of the later maximums on record and extent was near-normal early in the melt season , but still the 2012 minimum was by far the lowest minimum we 've seen . '' Meanwhile , the summer minimum ice extent reached in the Antarctic was one of the highest recorded , NOAA said . But this is n't cause for much optimism faced with evidence of a warming planet . `` Over the span of the satellite record , Arctic sea ice has been declining significantly , while sea ice in the Antarctic has increased very slightly , '' the NOAA news release said . `` Recent research demosntrates that the Antarctic gains do not balance out the Arctic losses : globally , sea ice extent has decreased over the past several decades . '' According to the NSIDC , sea ice in the Arctic appears to play a more important role in regulating global temperatures than that in the Antarctic .
scientists say that sea ice appears to have set a record low maximum extent this winter . Barring an unlikely late stage in sea ice growth , the 2015 maximum is 200 million square kilometers .