M. Sturm Mark C. Serreze J.P. McFadden J.R. Key A.H. Lloyd A. D. McGuire T.S. Rupp A.H. Lynch Joshua P. Schimel J. Beringer W.L. Chapman H.E. Epstein E.S. Euskirchen L. D. Hinzman G. Jia C.-L. Ping K.D. Tape C.D.C. Thompson D.A. Walker J.M. Welker F. S. Chapin III 2005 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. application/pdf 10.1126/science.1117368 en Role of land-surface changes in arctic summer warming article