Sea Ice Extent

August's Northern Hemisphere
Sea Ice Extent plot

Arctic sea ice continued its annual decline, typically reaching a September minimum. The August 2010 average Arctic sea ice extent—which is measured from passive microwave instruments onboard NOAA satellites—was 6.0 million square kilometers. This value is 22.0 percent or 1.70 million square kilometers below the 1979–2000 average—the second lowest August sea ice extent on record, behind 2007. This was the 14^th consecutive August with sea ice extent below the long-term average. August 1996 was the last year that had above-average sea ice extent. According to the National Snow and Ice Data Center (NSIDC), the Arctic dipole anomaly returned during August 2010, bringing warm southerly winds into the Beaufort and Chukchi seas, where temperatures were 1°-3°C (1.8°F-5.4°F) above average during the month. The warmer-than-average conditions enhanced melting in this area. Arctic sea ice extent for August has decreased at an average rate of 8.9 percent per decade.

August's Southern Hemisphere
Sea Ice Extent plot

As the Arctic sea ice extent contracts (during the Northern Hemisphere warm season), the Antarctic sea ice extent expands (during the Southern Hemisphere cold season). During August 2010, the Southern Hemisphere sea ice extent reached its largest extent on record for August, 4.1 percent above the 1979–2000 average. This is the second consecutive August with above-average Southern Hemisphere sea ice extent. Southern Hemisphere sea ice extent for August has increased at an average rate of 0.6 percent per decade.

For further information on the Northern and Southern Hemisphere snow and ice conditions, please visit the NSIDC News page, provided by NOAA's National Snow and Ice Data Center (NSIDC).

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