User:Sagredo/sea ice history

Reliable measurements of sea ice edge begin within the satellite era in the late 1970s. It reveals that, since 1979, Arctic ice extent has been decreasing.

The Arctic sea ice September minimum extent reached new record lows in 2002, 2005, and 2007 (39.2 percent below below the 1979-2000 average). In 2007, Arctic sea ice broke all previous records by early August—a month before the end of melt season, with the biggest decline ever in arctic sea ice minimum extent, more than a million square kilometers. In the first time in human memory, the fabled Northwest Passage opened completely. The 2007 melting surprised and concerned scientists.

In 2008 and 2009, Arctic sea ice minimum extent was higher than 2007, but it did not return to the levels of previous years. "Arctic sea ice extent remains low; 2009 sees third-lowest mark"] Additionally, studies show a dramatic decline in ice age and thickness. The Catlin Arctic Survey reported an average thickness of 1.8 meters across the northern Beaufort Sea, an area that had traditionally contained older, thicker ice.

A leading expert on sea ice cover in the North Pole region, Peter Wadhams, head of the Polar Ocean Physics Group at the University of Cambridge, summarized the scientific consensus by saying:the Arctic will be ice-free in summer within about 20 years, and that much of the decrease will be happening within 10 years.”