The U.S. National Snow and Ice Data Center (NSIDC) has released a detailed analysis of the 2012 Arctic sea ice extent, which reached a record low.
By contrast, winter sea ice extent in Antarctica has reached a record high. The Antarctic extent increase is an probable response to changes in circulation patterns in the Southern Hemisphere, according to NSIDC.
Arctic sea ice extent averaged for September 2012 was 3.61 million square kilometers. This was 3.43 million square kilometers below the average for 1979 to 2000, the period of available sea observations form space, and 690,000 square kilometers less than the previous record low for the month that occurred in 2007. (Graphic of ice extent 1979-2012)