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New low for winter Arctic sea ice cover - tied with 2005

  • 03 Mar 2011, 00:00
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Arctic Sea Ice 28February

Arctic sea ice continues to decline, as new data from the NOAA National Snow and Ice Data Centre shows. The extent of winter sea ice cover is at a record low - tied with 2005.

The amount of Arctic sea ice has been declining at around 13% per decade since satellite records began in 1979, in response to factors associated with global warming. The rate of warming in the Arctic is around twice as fast as the rest of the globe, partially as a result of this loss of sea ice. This is because ice counters regional warming by reflecting heat, therefore loss of ice reduces the ability to reflect heat, causing additional regional warming.

The declining trend in Arctic sea ice is complicated by a seasonal cycle in ice extent. Arctic sea ice grows in the cold winter months and retreats in the warmer summer months. This means that the area covered by Arctic sea ice alternates between extensive winter coverage, reaching a peak in February/March, and limited summer coverage.

However, this seasonal pattern takes place in the context of an overall declining trend in Arctic sea ice coverage. This year, winter ice coverage has reached a new low, with the US National Snow and Ice Data Centre reporting:

Sea ice extent averaged over the month of February 2011 was 14.36 million square kilometers (5.54 million square miles). This was a tie with the previous record low for the month, set in 2005. February ice extent remained below normal in both the Atlantic and Pacific sectors, particularly in the Labrador Sea and the Gulf of St. Lawrence.

The 2007 IPCC report predicted that summer Arctic sea ice is likely to disappear altogether by the end of the 21st century. However, recent summer melting of Arctic sea ice has been even more extensive than predicted in the IPCC report, leading to recent predictions of ice-free summer seas in the Arctic within decades.

3.10pm - Updated with some extra information from the NSIDC.

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