Study Finds That Reductions in Sea Ice Cover and Thickness Is The Major Cause of Polar Warming Amplification
In a process called polar amplification, the polar regions have been warming faster than the tropics. Although some research has attributed that amplification to upper-atmosphere transport processes, a new study by researchers at the University of Melbourne, Australia, now shows that reductions in sea ice cover and thickness—due to rapid melting— are responsible for most of the recent polar amplification.
A paper on their work was published in the 29 April issue of the journal Nature.
The sea ice acts like a shiny lid on the Arctic Ocean. When it is heated, it reflects most of the incoming sunlight back into space. When the sea ice melts, more heat is absorbed by the water. The warmer water then heats the atmosphere above it. What we found is this feedback system has warmed the atmosphere at a faster rate than it would otherwise.
—Lead author Dr. James Screen
Using the latest observational data from the European Centre for Medium-Range Weather Forecasting, Screen was able to uncover a distinctive pattern of warming, highly consistent with the loss of sea ice.
James A. Screen & Ian Simmonds (2010) The central role of diminishing sea ice in recent Arctic temperature amplification. Nature, Vol. 464, No. 7293, p1334 doi: 10.1038/nature09051