Arctic sea ice levels fall

mongabay.com
October 4, 2006

Arctic sea ice fell to the fourth lowest level on record according to researchers at the University of Colorado at Boulder.

CU-Boulder Research Professor Mark Serreze of the National Snow and Ice Data Center Sea said that sea ice is declining at about 8.6 percent per decade, or at about 23 million square miles per year. Serreze said that this year would have likely been a record had it not been for cool August temperatures.

Sea ice extent for September 26, 2006.Figure 1 shows the updated image of sea ice extent. Most notably, the polynya in the Beaufort Sea has become smaller because of new ice formation along its edges. The polynya will probably completely freeze over in the next few weeks, if not sooner.

"If fairly cool and stormy conditions hadn't appeared in August and slowed the rate of summer ice loss, I feel certain that 2006 would have surpassed last year's record low for September sea ice," said Serreze.

In 2005 Arctic the extent of Arctic sea ice was 20 percent lower than the average ice extent from 1978 to 2001, or about 500,000 square-miles less than normal.

"At this rate, the Arctic Ocean will have no ice in September by the year 2060," said CU-Boulder researcher Julienne Stroeve. "The loss of summer sea ice does not bode well for species like the polar bear, which depend on the ice for their livelihood."

The researchers said that the 2006 season was characterized by a large area of open water -- called a polynya -- that formed north of Alaska. The ice-free area was larger in area than Britain and theoretically would have allowed a ship to pass from Northern Siberia to the North Pole without much difficulty. No one is certain was triggered the formation of the polynya but warming temperatures and thinning sea ice could make them more common in the future.

"Melting ice means more of the dark ocean is exposed, allowing it to absorb more of the sun's energy, further increasing air temperatures, ocean temperatures, and ice melt," said CU-Boulder scientist Ted Scambos. "It seems that this feedback, which is a major reason for the pronounced effects of greenhouse warming in the arctic, is really starting to kick in." 

"I'm not terribly optimistic about the future of the ice," Serreze added. "As greenhouse gases continue to rise, the Arctic will continue to lose its ice. You just can't argue with the physics."