Sea Ice Extent, Area Still Spiralling Downward

JAXA sea ice extent measurements showed another substantial drop today. According to the agency, sea ice extent has now shrunk to 3.68 million square kilometers. Cryosphere Today also noted another large drop with sea ice area now at 2.44 million square kilometers. Both these measurements are substantial new records in the range of half a million square kilometers below previous records.

In context with previous sea ice extent, the early 1980s averaged about 6.0 million square kilometers at end of season and the 1950s averaged about 10 million square kilometers at end of season. At the current measure, we are more than 63% below the mid-20th century average.

Anyone making claims of ‘sea ice recovery’ clearly is unaware of these dramatic numbers.

Rates of fall are still rapid for this time of year. However, as September continues, the seasonal switch toward cooler conditions is more and more likely to slow and/or stop ice melt. The typical date for ice melt cessation is September 15th. We are now less than two weeks from that date.

It is worth noting, however, that Arctic weather tends to be highly variable. During the record 2007 melt season, melt continued until the beginning of October. Some recent years have also seen the cessation of melt near the end of August. So the depth of the current record will depend, in large part, on weather over the coming days and weeks.

One final point… It is important to note that the current rate of decline for both sea ice extent and area is greater than that seen even in 2007. If this is an indicator, it may well point to a longer than normal melt season.

Links:

http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm

http://arctic.atmos.uiuc.edu/cryosphere/

http://nsidc.org/arcticseaicenews/

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