German researchers have revealed that the area covered by Arctic sea ice has reached it lowest point [View All]

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since the start of satellite observations in 1972

http://www.physorg.com/news/2011-09-arctic-ice-historic-scientists.html

"On September 8, the extent of the Arctic sea ice was 4.240 million square kilometres (1.637 million square miles). This is a new historic minimum," said Georg Heygster, head of the Physical Analysis of Remote Sensing Images unit at the University of Bremen's Institute of Environmental Physics. The new mark is about half-a-percent under his team's measurements of the previous record, which occurred on September 16, 2007, he said. According to the US National Snow and Ice Data Center (NSIDC), the record set on that date was 4.1 million sq km (1.6 sq mi). The discrepancy, Heygster explained by phone, was due to slightly different data sets and algorithms.

"But the results are internally consistent in both cases," he said, adding that he expected the NSIDC to come to the same conclusion in the coming days. Arctic ice cover plays a critical role in regulating Earth's climate by reflecting sunlight and keeping the polar region cool. Retreating summer sea ice -- 50 percent smaller in area than four decades ago -- is described by scientists as both a measure and a driver of global warming, with negative impacts on a local and planetary scale. It is also further evidence of a strong human imprint on climate patterns in recent decades, the researchers said.

"The sea ice retreat can no more be explained with the natural variability from one year to the next, caused by weather influence," Heygster said in an statement released by the university. "Climate models show, rather, that the reduction is related to the man-made global warming which, due to the albedo effect, is particularly pronounced in the Arctic." Albedo increases when an area once covered by reflective snow or ice -- which bounces 80 percent of the Sun's radiative force back into space -- is replaced by deep blue sea, which absorbs the heat instead. Temperatures in the Arctic region have risen more than twice as fast as the global average over the last half century.

The ice was so gone this year even a single handed sail boat went solo through the northwest passage this summer. http://www.solotheamericas.org/