Global Climate Change Impacts in the United States 2009 Report Legacy site

Human influence has previously been identified in the observed loss of Arctic sea ice, but this hypothesis has not yet been tested with a formal optimal detection approach. By comparing observed and multi-model simulated changes in Arctic sea ice extent during 1953-2006 using an optimal fingerprinting method, we find that the anthropogenic signal first emerged in the early 1990s, indicating that human influence could have been detected even prior to the recent dramatic sea ice decline. The anthropogenic signal is also detectable for individual months from May to December, suggesting that human influence, strongest in late summer, now also extends into colder seasons. Citation: Min, S.-K., X. Zhang, F. W. Zwiers, and T. Agnew (2008), Human influence on Arctic sea ice detectable from early 1990s onwards, Geophys. Res. Lett., 35, L21701, doi:10.1029/2008GL035725.