Sunday, February 22, 2009

Faster And Faster
Scientists are changing their computer models because Arctic ice is melting faster than their predictions.
New research has revealed that melt-water pooling on the Arctic sea ice is causing it to melt at a faster rate than computer models had previously predicted.

Scientists have been struggling to understand why the northern sea ice has been retreating at a faster rate than estimated by the most recent assessment of the Intergovernmental Panel on Climate Change (IPCC), in 2007.

The IPCC's computer models had simulated an average loss of 2.5% in sea ice extent per decade from 1953 to 2006. But in reality the Arctic sea ice had declined at a rate of about 7.8% per decade.

Arctic sea ice has retreated so much that in September 2007 it covered an all-time low area of 4.14m km sq, surpassing by 23% the previous all-time record set in September 2005.

And during the summer of 2008, the north-west and north-east passages - the sea routes running along the Arctic coastlines of northern America and northern Russia, normally perilously clogged with thick ice – were ice-free for the first time since records began in 1972.

Part of the reasons for the discrepancy has to do with melt ponds, which are pools of melted ice and snow that form on the sea ice when it is warmed in spring and summer. As they are darker than ice and snow, they absorb solar radiation rather than reflect it, which accelerates the melting process.

The climate crisis is happening now. In 2006, scientists were predicting ice free Arctic summers by 2050. In 2008, the prediction was for ice free Arctic summers by 2030. The crisis is moving exponentially. It is going to be an interesting couple of decades.

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