'Emperors of the Ice' Losing Their Home

Sept. 21, 2006 — -- They are the emperors of the ice, but their dominion is disappearing. The polar bear's frozen hunting grounds are melting.

Thanks to the World Wildlife Fund, ABC News had an opportunity to see firsthand the threat global warming poses to polar bears. WWF is sponsoring research with the Canadian Wildlife Service to document the impact of climate change on the bears.

Churchill, Manitoba is a town so small and so remote, there's no cell phone service at all. The population is just 800, with 930 polar bears living just outside the town.

Churchill boasts the world's only polar bear jail. Every year, about a hundred hungry bears wander into town looking for food, endangering themselves and the citizens of Churchill.

Conservation officials shoot them with tranquilizers and transport them to the cooler. The bears' jail sentence: 30 days, no rations -- just snow and water. The town hopes that strategy will gently persuade them not to come back.

The bears are hungry for a reason. Every year, their prime hunting season grows a little shorter. Polar bears only hunt when there's sea ice, and because of global warming, the ice on Hudson Bay melts a little earlier each year.

Over the past 15 years, summer has gradually lengthened by more than three weeks in the region around Churchill. That means bears have lost nearly a month of their hunting season.

"I've seen it firsthand -- bears in worse shape, and fewer bears on the tundra," said Nick Lunn, a polar bear researcher from the University of Alberta.

When Lunn began his study, there were around 1,200 bears in Western Hudson Bay. Since 1989, his research team has documented a 22 percent decline in the population.

Lunn and his team took us out into Wapusk National Park, on the shores of Hudson Bay. There are no roads at all leading into the park. The place is truly wild. And this time of year, it is teeming with polar bears, which makes sense since "wapusk" is the Cree word for "white bear."