NCSIDC has it’s monthly analysis for September done and as expected, it ain’t pretty.
Arctic sea ice extent averaged for September 2012 was the lowest in the satellite record, and was 16% lower than the previous low for the month, which occurred in 2007. Through 2012, the linear rate of decline for September Arctic ice extent over the satellite record is now 13.0% per decade, relative to the 1979 to 2000 average. The six lowest September ice extents over the satellite record have all occurred in the last six years. Compared to the 1979 to 2000 average ice conditions, the September 2012 ice cover represents a 49% reduction in the area of the Arctic Ocean covered by sea ice. It is 2.91 million square kilometers (1.12 million square miles), or 45%, below the 30-year average over 1981 to 2010.
And don’t let the denial crowd distract you with antarctic sea ice, which also set a record. These two records are <cough> poles apart! Just compare the images below and note where the grey 2 standard deviation area is in relation to the record breaking observations.
These are not comparable events. And don’t buy the denialist line that the extreme arctic melt was all due to weather. True that there was an unusual, strong and long-lived arctic cyclone in mid August, but melt rates before and after were still unusually high. The main factor was the young age (thinness) of the ice which is a result of climate change. More on the weather:
Weather conditions prevailing over the summer of 2012 were quite different from those in 2007. The summer of 2007 featured unusually high sea level pressure centered north of the Beaufort Sea and Greenland, and unusually low pressure along northern Eurasia, bringing in warm southerly winds along the shores of the East Siberian and Chukchi seas (3 to 5 degrees Celsius, or 5 to 9 degrees Fahrenheit above normal), favoring strong ice melt in these sectors and pushing the ice away from the coast, leaving open water. The pressure pattern also favored the transport of ice out of the Arctic Ocean and into the North Atlantic through Fram Strait.
In contrast, the summer of 2012 saw unusually low pressure along the Eurasian coastal seas and extending eastward into the Beaufort sea, most prominently over the East Siberian Sea, with unusually high pressure centered over Greenland and the northern North Atlantic. Air temperatures for summer 2012 were above average over most of the Arctic Ocean (1 to 3 degrees Celsius, or 2 to 5 degrees Fahrenheit), most prominently over the Beaufort Sea, where
So, 3-5 oC above normal in 2007, only 1 to 3 oC above normal this year. Speaking of the age of the ice, don’t miss this graphic:
Check out the press release for more details about this years truly extraordinary melt season, and be sure the record breaking is not over yet.
But it will be soon.