An eventful summer sea ice melt season has ended in the Arctic. Ice extent reached its low for the year, the third lowest in the satellite record, on 19 September. Both the Northwest Passage and the Northern Sea Route were open for a period during September.
Ice extent for September 2010 was the third lowest in the satellite record for the month, behind 2007 (lowest) and 2008 (second lowest). The linear rate of decline of September ice extent over the period 1979 to 2010 is now 81,400 square kilometers (31,400 square miles) per year, or 11.5% per decade relative to the 1979 to 2000 average. Sea ice extent at the end of the melt season is shaped by conditions in the atmosphere and ocean, as well as the condition of the ice cover itself.
The U.S. National Ice Center declared both the Northwest Passage and the Northern Sea Route open for a period during September. Two sailing expeditions, one Norwegian and one Russian, successfully navigated both passages and are nearing their goal of circumnavigating the Arctic. (Image credit: National Snow and Ice Data Center)
>Monthly September ice extent for 1979 to 2010 shows a decline of 11.5% per decade.  (Source: National Snow and Ice Data Center)
>Arctic Sea Ice Extent for September 2010  (Source: National Snow and Ice Data Center)
Source and further information: Press release National Snow and Ice Data Center (NSIDC)