Arctic sea ice begins annual retreat
March 31st, 2009The National Snow and Ice Data Service (NSIDC) reports Arctic sea ice reached its maximum extent for the year on February 28, at 15.14 million square kilometers (5.85 million square miles). The maximum extent was 720,000 square kilometers (278,000 square miles) below the 1979 to 2000 average of 15.86 million square kilometers (6.12 million square miles), making it the fifth-lowest maximum extent in the satellite record. The six lowest maximum extents since 1979 have all occurred in the last six years (2004 to 2009).
In the beginning of March, ice extent began to decline, and it appeared that Arctic sea ice had reached its maximum extent. However, in the second week of March the ice edge began to expand again, but it failed to again reach the the extent seen on February 28. Fluctuations in the extent of Arctic sea ice are not unusual near the annual maximum, as the ice edge at this time of year consists of thin ice that is sensitive to temperature changes and easily redistributed by storm winds.