Arctic Sea Ice At Or Near Record Low

Extent of Arctic sea ice on September 14, 2011, as estimated by the University of Bremen.

The annual summer melt of Arctic sea ice is at, or very near to, its greatest extent with conflicting reports saying that it has either reached a new record or has come in at second place.

Researchers at Germany’s University of Bremen initially said that sea ice extent had dropped to below the record low observed in 2007, based on satellite observations that go back to 1972.

But the U.S. National Snow and Ice Data Center (NSIDC) later said its maps and observations suggest Arctic sea ice on Sept. 10 was still 42,470 square miles greater in coverage than the 2007 measurements on the same date.

The approaching Arctic winter has probably put a halt to this season’s melt, making it unlikely the 2007 record will be broken, NSIDC said in a statement.

The discrepancy between the German and U.S. reports is said to be due to the different satellite observation technologies and algorithms used to create ice-coverage maps.

Graphic: University of Bremen