Arctic Sea ice recovered slightly this year

Compared to the record-setting low years of 2007 and 2008, the Arctic Sea ice has made a slight recovery in 2009, according to the University of Colorado at Boulder’s National Snow and Ice Data Center. Despite this positive change, the minimum sea ice extent in 2009 was the third lowest since satellite record-keeping started in 1979.

“It’s nice to see a little recovery over the past couple of years, but there’s no reason to think that we’re headed back to conditions seen in the 1970s,” said NSIDC Director Mark Serreze, also a professor in CU-Boulder’s geography department. “We still expect to see ice-free summers sometime in the next few decades.”

The standard measurement for climate studies is the average ice extent during September. This September, the average Arctic Sea ice extent was 5.36 million square kilometres, which is 1.06 million square kilometres more than September 2007 and 690,000 square kilometres more than September 2008.

According to Mike Steele, Senior Oceanographer at the University of Washington, the decrease in ice loss is probably due to cloudy skies during late summer. Sea surface temperatures in the Arctic were higher than normal this season, but slightly lower than in 2007 and 2008 – most likely due to the presence of clouds this year. Atmospheric patterns in August and September also helped spreading the ice pack over a larger area.

Arctic sea ice follows an annual cycle of melting during the warm season and refreezing in the winter, and the extent of Arctic sea ice has always varied due to changing atmospheric conditions. During the past 30 years, there has however been a dramatic overall decline in Arctic sea ice extent.