THIS WEEK IN SCIENCE

摘要

The climate and environment of the Arctic have changed drastically over the short course of modern observation. Kaufman et al. (p. 1236) synthesized 2000 years of proxy data from lakes above 60° N latitude with complementary ice core and tree ring records, to create a paleoclimate reconstruction for the Arctic with a 10-year resolution. A gradual cool-ing trend at the start of the record had reversed by the beginning of the 20th century, when tempera-tures began to increase rapidly. The long-term cool-ing of the Arctic is consistent with a reduction in summer solar insolation caused by changes in Earth's orbit, while the rapid and large warming of the past century is consistent with the human-caused warming.