Alaska Science Center
Forecasting the Future Status of Polar Bears
During 2007, USGS led an intensive effort to project future status of polar bears, coupling empirical data with information on future Arctic sea ice from IPCC 4th Assessment (AR4) models. This research projected major declines by mid-century in polar bear distribution and abundance. This finding became an important consideration in the decision to list polar bears, in 2008, as a threatened species under the Endangered Species Act (ESA). Arctic sea ice continues to retreat at a faster rate than models predict, and this phenomenon (“faster than forecast”) increases the urgency for managers to address climate change issues in the Arctic. A primary focus of the current USGS research program on polar bears is to refine and enhance the 2007 forecasting models. This new work is supported by the Changing Arctic Ecosystems initiative. Our goals in this initiative are to refine estimates of the scale and mechanisms of population responses for two key species tied to sea ice, the polar bear and the walrus, and to identify and reduce the sources of uncertainty in those predictions.