Scientists studying a polar bear in Alaska.
Flickr, Alaska Region U.S. Fish & Wildlife Service (Steve Amstrup/USGS)
A study published last week in Ecological Applications has shown that polar bear populations in the southern Beaufort Sea region have declined by 40 percent.
Scientists from the U.S. Geological Survey (USGS) and Environment Canada tagged and released polar bears in eastern Alaska and western Canada and found their numbers dropped from 1,600 in 2004 to 900 in 2010.
Worse still, only two of the 80 polar bear cubs that they tracked between 2003 and 2007 survived. About half of the cubs should normally survive.
Polar bear populations are declining because of Arctic ice melting due to climate change. Polar bears rely on Arctic sea ice for habitat as well as for the seals that share the ice. Arctic ice has been retreating by 12 percent per decade since the late 1970s and the decline has worsened since 2007, according to NASA.
The southern Beaufort Sea represents a southern portion of polar bear habitat, so it is warming faster and is more susceptible to melting sea ice. It is also a region that oil and gas companies have been trying to develop.
View a map of the Beaufort Sea region below:
The USGS estimated in 2007 that the global polar bear population will shrink to a third of its current size by 2050, due to loss of habitat and less access to prey. This recent study verifies those predictions and suggests the rate of decline may even be accelerating.
With less ice, bears have had to swim farther - one mother tracked in 2011 had swum for 426 miles over nine days and her cub died. You can watch a video of swimming bears here.
Polar bears are considered threatened under the federal Endangered Species Act. Many conservationist organizations have advocated for their species' status to be changed to endangered.
We are also advocating for Alaska lands and waters to be designated as protected habitat for this struggling species
Congress is expected to renew its efforts to allow drilling in the Arctic National Wildlife Refuge coastal plain, which contains the greatest density of on-shore polar bear dens in America’s Arctic and is the most important on-shore denning habitat for the Beaufort Sea polar bear population. Oil drilling in the Arctic Refuge coastal plain and the adjacent Arctic Ocean is the last thing that vulnerable polar bears need.