Arctic ice melts quickly through July

Arctic sea ice extent for the month of July was the third lowest for that month in the satellite record, after 2007 and 2006, according to National Snow and Ice Data Center.

The average rate of melt in July 2009 was nearly identical to that of July 2007. A strong high-pressure system, similar to the atmospheric pattern that dominated the summer of 2007, brought warm winds and clear skies to the western Arctic, promoting ice melt.

Overview

Sea ice extent averaged over the month of July 2009 was 8.81 million square kilometers (3.40 million square miles). This was 680,000 square kilometers (263,000 square miles) above the record low that occurred in July 2007, 250,000 square kilometers (97,000 square miles) below July 2008, and 1.29 million square kilometers (498,000 square miles) below the 1979 to 2000 average. Sea ice extent is unusually low in the Kara Sea, Baffin Bay, and along the Russian coast. The only area with significant above-average ice extent is southern Hudson Bay.

The average pace of ice loss during July 2009 was nearly identical to that of July 2007. Ice loss sped up during the third week of July, and slowed again during the last few days of the month.

Averaged for the month, July 2009 saw a decline rate in ice extent of 106,000 square kilometers (41,000 square miles) per day. For comparison, the rate of decline for July 2007 was 107,000 square kilometers (41,000 square miles) per day and the July 2008 rate of decline was 94,000 square kilometers (36,000 square miles) per day. The Arctic Ocean lost a total of 3.19 million square kilometers (1.23 million square miles) of ice during July 2009, and dropped below ice extent at this time in 2008.

July 2009 compared to past years

Ice extent averaged for July 2009 was the third lowest in the satellite record for the month of July. The long-term trend indicates a decline of 6.1 per cent per decade in July ice extent since 1979, relative to the 1979 to 2000 average, an average of 62,000 square kilometers (24,000 square miles) of ice per year.