Study links humans to warming in the Arctic
WASHINGTON - Human-generated greenhouse gas emissions have helped reverse a 2,000-year trend of cooling in the Arctic, prompting warmer average temperatures in the past decade that now rank higher than at any time since 1 B.C., according to a study published yesterday in the online version of the journal Science.
The analysis provides one of the broadest pictures to date of how industrial emissions have shifted the Arctic’s longstanding climate patterns. Coupled with a separate report on the region issued Wednesday by the World Wildlife Fund, it suggests human-induced changes could transform not only the Arctic but climate conditions across the globe.
“It’s basically saying the greenhouse gas emissions are overwhelming the system,’’ said David Schneider, one of the article’s coauthors.
The study involved 30 researchers from the United States, Britain, Denmark, Norway, Canada, and Finland and reconstructs the Arctic’s climate in the distant past. One of the study’s authors is Raymond Bradley, director of the Climate System Research Center at the University of Massachusetts at Amherst.
Some skeptics have argued that the fact that Earth wobbles in its axis of rotation has helped determine recent warming, rather than human activity. But the new study shows that this wobble - which affects how much sunlight Earth receives in the middle of the summer - actually accounts for a long-term cooling trend in the Arctic, which has been reversed only in the past half-century.
