Figure 7. September Arctic sea ice is now declining at a rate of 11.5% per decade, relative to the 1979 to 2000 average. Arctic sea ice reaches its minimum each September. The graph above shows the average monthly Arctic sea ice extent in September from 1979 to 2012, derived from satellite observations. The September 2012 extent was the lowest in the satellite record. National Snow and Ice Data Centre http://nsidc.org/ and NASA http://climate.nasa.gov/key_indicators