Role of land-surface changes in arctic summer warming.
A major challenge in predicting Earth's future climate state is to understand feedbacks that alter greenhouse-gas forcing. Here we synthesize field data from arctic Alaska, showing that terrestrial changes in summer albedo contribute substantially to recent high-latitude warming trends. Pronounced terrestrial summer warming in arctic Alaska correlates with a lengthening of the snow-free season that has increased atmospheric heating locally by about 3 watts per square meter per decade (similar in magnitude to the regional heating expected over multiple decades from a doubling of atmospheric CO2). The continuation of current trends in shrub and tree expansion could further amplify this atmospheric heating by two to seven times.
Chapin
F S
FS
Institute of Arctic Biology; University of Alaska Fairbanks, Fairbanks, AK 99775, USA. terry.chapin@uaf.edu
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D000413:Alaska; D001110:Arctic Regions; D017752:Greenhouse Effect; D028222:Picea; D012621:Seasons; D014197:Trees