Arctic Sea Ice Drops
Preliminary figures provided by the National Snow and Ice Data Center, part of the University of Colorado at Boulder, states that melting Arctic sea ice has shrunk to a 29 year low, below the minimum set in 2005 and is about 38% lower than the climatological average.
Since the earliest measurements in 1979, NASA scientists have been observing the decline of the Arctic Sea cover at the rate of 10 % per decade. They are working to understand this sudden decrease of sea ice and what it means for the future of Earth’s northern polar region. The sea ice cover reaches it’s minimum extent at the end of the summer and the ice remains is called the perennial ice cover, consisting mainly of thick multi-year ice flows. “The decline in the amount of thick ice that survives the summer melt season this year is quite remarkable,” said Josefino C. Comiso, senior scientist at NASA’s Goddard Space Flight Center, Greenbelt MD. He adds that the extent of this “perennial” sea ice and the area it covers are both nearly 38 % lower than average.
Compared to the record low in 2005, the extent and area are 24% and nearly 26% lower this year, respectively. After thirty years of continuous satellite observations as to how the Arctic Sea ice behaves, this kind of drop in sea ice takes about three years to happen. The rapid trend of the perennial ice previously reported in 2002 appears to be in an accelerated mode, observed by Comiso. On the Aqua Satellite is the “Advanced microwave instrument” that NASA launched in 2002. It provides a view of sea ice dynamics in greater detail than ever before. Information gathered is used to study polar bear habitats and the unique movements of the sea ice from season to season.
AMSR - E is a giant joint project of the National Space Development and NASA. Comiso believes that the rapid decline in sea ice may be because of changes in climate brought on by the lack of sea ice itself. Light from the sun is reflected by polar ice. As the ice melts, less sunlight gets reflected into space. The heat is absorbed into oceans and land, raises the overall temperature and fuels more melting. This positive feedback loop called ice albedo feedback which causes loss of the sea ice to be self-compounding. The more it disappears, the more likely it is to continue to disappear.
In Sept. 2007, for the first time since satellite records began the Northwest Passage, which was a direct route from Europe to Asia for ships traveling through the Arctic, was totally ice-free. “This year, the amount of ice is so far below that of previous years that it really is cause for concern. The trend in decreasing ice cover seems to be getting stronger as time goes by,” said Waleed Abdalati, head of Goddard’s Cryospheric Science Branch.
This entry was posted on Friday, February 22nd, 2008 at 3:03 am and is filed under Public Relations, Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
