NSIDC 9/16 Update - Arctic Ice Decline Sets New All-Time Record - 416K Sq. Miles Below 2005 Record

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Figure 1: Sea ice extent for September 16, 2007



Current sea ice conditions: September 16, 2007

Figure 1 provides the updated map of sea ice extent for September 16, 2007. Sea ice extent now stands at 4.14 million square kilometers (1.63 million square miles). The magenta line shows the median September monthly extent based on data from 1979 to 2000. The main, deep channel of the Northwest Passage (Lancaster Sound to M'Clure Strait) has been open, or nearly ice-free, for about five weeks (since August 11, approximately). Of note is the northernmost ice edge ever recorded, at 85.5 degrees North, near the 160 degrees east longitude line.

Sea ice is still declining, although the rate is very slow at present. Sea ice extent at this time of year can vary from day to day, as regions within the Arctic have small episodes of melt, freeze, or wind movement of the ice, just before the strong autumn cooling. As of September 16, sea ice extent was 4.14 million square kilometers (1.59 million square miles), surpassing the previous one-day record of September 20–21, 2005, by more than 1.2 million square kilometers (461,000 square miles).

Due to the variability of sea ice at this time of year, the National Snow and Ice Data Center determines the minimum using a five-day running mean value. This value continues to decline as of our information on September 17. In past years, the minimum has occurred as early as September 4, and as late as September 28. In recent years, there has been a trend towards later final minima dates; see 2005 in Figure 2.

Figure 2: Summer melt season Arctic sea ice extent



Current sea ice conditions in context

Figure 2 is the updated time series of daily ice extent for 2007, which can be compared to the time series for 2005 and to the 1979 to 2000 average. Compared to conditions cited in our last entry on September 9, we have lost an additional 100,000 square kilometers (38,000 square miles) of ice.

EDIT

http://nsidc.org/news/press/2007_seaiceminimum/20070810_index.html

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1. did you see the chart from last week showing where ice had always previously been found?

The whole sector in the western sea has always had ice in it, but not this year. Also apparently an expedtition on the Polar Stern noted that the ice that was there is a foot thinner than usual.

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2. Yeah, according to the Polarstern/Wegener report, much of the ice has lost 50% of thickness

They didn't say how much (i.e. "large areas) at least in the reports I saw, but stunning nonetheless.

It took from 1970 until 2000 for average pack ice thickness to go from three meters to two. It took six years for that average to fall by another half.

Meanwhile, OJ's in jail! Will he beat the rap?!!?