Loss of reflectivity in the Arctic is double the estimate used in current state-of-art climate models according to new analysis of the Northern Hemisphere's "albedo feedback" over a 30-year period.
The albedo feedback is the change in the reflectivity of surfaces in a constant reinforcing feedback loop. In the Arctic snow and ice is highly reflective. Global warming has reduced sea ice exposing darker ocean and increased the size of dark melt pools on the Greenland ice sheet, which then increases the warming effect on ice in a positive feedback.
"The cryosphere isn't cooling the Earth as much as it did 30 years ago, and climate model simulations do not reproduce this recent effect," said Karen Shell, an Oregon State University atmospheric scientist and one of the authors of the study. "Though we don't necessarily attribute this to global warming, it is interesting to note that none of the climate models used for the 2007 International Panel on Climate Change report showed a decrease of this magnitude."
