April 8, 2010

Arctic Ice Melt Starting Late

The U.S. National Snow and Ice Data Center reports that the extent of sea ice over the Arctic Ocean grew until the last day of March, which is the latest the annual melting season has begun in 31 years of satellite records.

The center said in a statement on Wednesday that cold weather and winds from the north over the Bering Sea and Barents Sea meant the area of ocean covered by ice expanded through last month.  That is two days later than in 1999, the previous latest start to a melting season since satellite monitoring began in 1979.

Scientists highlighted declining Arctic sea ice as an indicator of global warming.  The NSIDC said the Arctic Ocean could be largely ice-free during the summer by 2030.  The group said that although this year's melting season has started late, it probably would not have an impact on the extent of ice in the summer.

"The ice that formed late in the season is thin and will melt quickly when temperatures rise," the NSIDC said.

The Boulder, Colorado based center said the peak ice extent of 5.89 million square miles "approached" the average for the years 1979 to 2000.  It was about 258,000 square miles over the record low ice peak of 2006.

Melting started in March and then reversed during a cold snap, which delayed the annual freeze.

The researchers said that Arctic sea ice shrank in September of 2009 to its third-lowest summer minimum on record, remaining "well outside the range of natural variability."


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