Arctic sea ice continued to expand during November, gaining 2.24 million square kilometers (865,000 square miles) of ice since the beginning of the month. However, Sea ice extent for November averaged 10.24 million square kilometers (3.95 million square miles). This is 750,000 square kilometers (290,000 square miles) below the 1981 to 2010 average extent and is the 6th lowest November extent in the 35-year satellite data record. As was the case for October 2013, sea ice extent for November 2013 remained within two standard deviations of the long-term 1981 to 2010 average.
The below average ice extent in the Arctic was largely due to a lack of ice in the Barents Sea, which has shown a pattern of low autumn and winter ice extent over the recent years. This November, the overall extent in the Barents Sea was the second lowest in the satellite record, with the lowest occurring in 2012.
The low ice in the Barents Sea is due to several possible factors. First, it could reflect the influx of warm ocean currents that inhibited ice growth. The atmosphere also played some role. Sea level pressure over the Arctic Ocean was lower than normal. November air temperatures in the Barents Sea were on the order of 2 to 4 degrees Celsius (4 to 7 degrees Fahrenheit) above average. The higher than average temperatures may also simply reflect the lack of sea ice in the Barents Sea. This is because under open water conditions, the ocean readily releases heat to the overlying atmosphere.
Including 2013, the linear trend in November ice extent is –4.9% per decade relative to the 1981 to 2010 mean, or –53,500 square kilometers per year (–20,700 square miles per year).
8 January 2014, LTEconomy
From NSIDC, December 2013