Every winter, the Arctic Ocean’s sea ice cover reaches a peak and then declines with the onset of spring. That peak, recorded this year on Thursday, was the lowest seen in 37 years of record keeping, federal scientists said yesterday. Sea ice covered just 5.6 million square miles of the Arctic Ocean on Thursday, about 5,000 square miles less than the previous record set last year, according to the National Snow and Ice Data Center (NSIDC) and NASA. The 1981-2010 average sea ice extent was 6 million square miles.
