|The polynya in the Beaufort Sea. The blueish tint of the ice near the polynya (red box) indicates that the ice is wet from surface melting . Click to enlarge. Source: NSIDC|
A giant polynya—an area of open water in sea ice—in the Beaufort Sea fully opened last week. The new polynya measures some 38,000 square miles and is “extremely unusual” according to scientists at the National Snow and Ice Data Center.
“The only time we’ve seen a similar polynya was in 2000. However, the 2000 formation was much smaller and closer to the ice edge, barely enclosed with ice.”
Some areas of the ocean show evidence of new ice formation as autumn cooling begins to take hold. However, at the same time, some areas south of the polynya that were formerly ice covered have continued to melt out. (See picture.)
|A wider view of the polynya. The pink line shows the average ice extent for September, the end of the summer melt season. Click to enlarge.|
So far, Arctic summer sea ice has shrunk to the fourth-smallest September minimum on record. Although some refreezing has begun, parts of the polynya are continuing to melt, so the final totals are uncertain.
A recent study from NASA shows that in 2005 and 2006, the Arctic winter sea ice maximum was about 6% smaller than the average amount over the past 26 years as well.
Speaking at the first ever Climate Clinic taking place at the Liberal Democrat Conference in Brighton (UK), Director of British Antarctic Survey, Professor Chris Rapley, described how satellite and field data reveal that changes are taking place in the Polar Regions faster than scientists had predicted even five years ago.
There are still major uncertainties about what will happen and how quickly, but a sea level rise of up to 5m could take place in the long-term unless greenhouse gas emissions are significantly and quickly curbed.