Arctic Sea Ice Still at Risk despite Cold Winter
19.03.2008 - Other
NASA satellite observations shows that a cold winter in some regions of the Arctic has yielded an increase in new (thin) sea ice, while the surface of older (thicker) sea ice has continued to decline.
Scientists 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. Because perennial ice is generally thicker ice and is thus more resilent to summer melting, scientists conclude that, overall, Arctic Sea ice is still at risk.
Whereas perennial sea ice used to cover 50-60 percent of the Arctic Ocean, this year it covers less than 30 percent, according to NASA-processed microwave data. Very old ice that has remained in the Arctic for at least six years comprised over 20 percent of the Arctic area in the mid to late 1980s, but this winter it decreased to just six percent. The latest observations from the National Snow and Ice Data Center (an organization partially funded by NASA) confirm this trend. Perennial sea ice dropped from about 40 percent of the total ice pack last year to 30 percent of total ice this winter.
