Researchers Say Arctic Sea Ice Still at Risk Despite Cold Winter

NASA researchers have using the latest satellite observations report that the Arctic is still on "thin ice" when it comes to the condition of sea ice cover in the region. A new area of sea ice has risen due to the colder-than-average winter in the Arctic this year. On March 18 the scientists said they believe that the increased area of sea ice this winter is due to recent weather conditions, while the decline in perennial ice reflects the longer-term warming climate trend and is a result of increased melting during summer and greater movement of the older ice out of the Arctic. Walt Meier of the National Snow and Ice Data Center at the University of Colorado, Boulder, says that as ice ages it will continue to grow and thicken, so that older ice is generally thicker. But this winter they have noticed that the ice is thinner than usual. Therefore it is in a more vulnerable state heading into the summer melt. To get a better understanding of the behavior of sea ice, NASA is planning a follow-on satellite mission, ICESat II, to launch in 2015. The Arctic sea grows and declines seasonally, ranging from an average minimum of 2.5 million square miles in the month of September to an average winter maximum extent of 5.9 million square miles in the month of March. The ice in the Arctic is much younger than normal, with vast regions now covered by first-year ice and much less area covered by multiyear ice. NASA satellites and scientists are continuing to keep a close watch on the conditions of the Arctic Ocean as the summer makes its way in. In doing this they are trying to better determine the extent of the perennial sea ice.

http://geology.com/nasa/arctic-sea-ice.shtml