Published on September 26th, 2012 | by Joshua S Hill7
Arctic Sea Ice Extent Concludes Summer Shrinkage at Record Minimum
How many posts will you see decrying the minimum sea ice extent of the Arctic Sea this year? My best bet is approximately 36, give or take three on either side. For CleanTechnica’s part, this should be our last, as the US National Snow and Ice Data Center (NSIDC) has released its preliminary report on 2012′s sea ice extent minimum.
According to NSIDC, “on September 16, Arctic sea ice appeared to have reached its minimum extent for the year of 3.41 million square kilometers (1.32 million square miles).”
This puts 2012 as the lowest seasonal minimum extent in the satellite record, which began back in 1979, despite the year being less extreme than 2007, when climatic conditions actively favoured summer ice loss.
The minimum extent — a preliminary result, given the possibility of a shift in wind patterns leading to a period of late season melt pushing the ice extent even lower — was reached three days later than the 1979 to 2000 average minimum date of September 13.
This year’s minimum was 760,000 square kilometers (293,000 square miles) below the previous record minimum extent in the satellite record, which occurred on September 18, 2007, and 49 percent below the 1979 to 2000 average.
Overall, there was a loss of 11.83 million square kilometers (4.57 million square miles) of ice since the maximum extent occurred on March 20, 2012, which is the largest summer ice extent loss in the satellite record, more than one million square kilometers greater than in any previous year.
NSIDC suggests that “the primary reason for the large loss of ice this summer is that the ice cover has continued to thin and become more dominated by seasonal ice.” What they mean is that instead of ice that has survived several summers and grown thick and strong, the ice that is melting each year is only formed the winter previously.
For more on the Arctic death spiral, check out this Arctic death spiral post from March, this post on Arctic ice melt projections for the coming years, this post on 2011′s Arctic sea ice minium (source of the image just above), this post on a range of climate science topics and how they’re misrepresented by Richard Linzen, or the NSIDC post linked below.