Shrinking ice could put polar bear on endangered list

Climate Ark, via Agence France-Presse: Melting Arctic sea ice due to global warming could cut the polar bear population by two-thirds over the next 50 years, the US Geological Survey (USGS) said in a series of studies released Friday. The nine studies could prompt the US Interior Department's Fish and Wildlife Service to list the polar bear as a threatened species. Polar bears depend on sea ice as a platform to hunt seals, their primary food. But sea ice is decreasing throughout their Arctic range due to climate change.

The USGS spent six months documenting the direct relationship between the presence of Arctic sea ice and the survival and health of polar bears. Its reports summarize and integrate results of a series of studies on polar bear populations, range-wide habitats and changing sea ice conditions in the Arctic. Models used by the USGS team project a 42 percent loss of optimal polar bear habitat from the Polar Basin during summer, a vital hunting and breeding period, by mid-century, the studies said.

Over the next six months, officials will seek public input on the studies to deepen their understanding of the migrating bears and their habits and better judge what will happen to the bears as Earth's atmosphere heats up and the polar ice recedes. In January 2008, the Fish and Wildlife Service is to make a recommendation on whether to list the polar bear as "threatened," which imposes restrictions on hunting and protects the habitat of the species until it recovers. A more serious listing under US law is the "endangered" category.

"This team has done a tremendous job in furthering polar bear science through the use of long-term observational measurements on polar bears, their habitats, and many other factors integrated into a range of new and traditional models," said Mark Myers, survey director.