Canada, whose frozen north is home to two-thirds of all polar bears, is contributing to the creatures' decline by failing to take action to curb its emissions of greenhouse gases, WWF-Canada official Peter Ewins said.

"There is rapidly mounting evidence that many polar bear populations are in crisis as a result of sea-ice habitat loss, over-hunting and industrial development pressures," said Ewins, head of species conservation at WWF-Canada.

"Without strong leadership from the prime minister (Stephen Harper) to change our outdated approach to how we manage our natural resources, some polar bear populations will become extinct by 2050," he warned in a press release.

The WWF statement was released as the Committee on the Status of Endangered Wildlife in Canada prepares to issue recommendations to the Harper government on Friday this week.

Polar bears' habitat on Arctic sea ice will continue to melt without an "aggressive plan" by Harper's government to reduce emissions, conserve energy and develop renewable energy, the environmental group said.

Over-hunting in the Nunavut and Greenland regions has contributed to a "massive" decline of 30 percent in the Baffin Bay polar bear population in the past 10 years, it said.

The group also noted the habitat of polar bears and whales in the Beaufort Sea is set to be sold off for oil and gas exploration on June 2, without "proper resource planning that would protect such sensitive wildlife habitats."

"Research is showing that increasing numbers of Beaufort Sea polar bears are starving and walking all the way to Russia, or far inland, in search of food," Ewins said.

Increasing numbers of the bears are being killed as they forage wider for food and come into contact with human settlements.

An emaciated mother bear and her two cubs were shot dead by Canadian police in early April at the community of Deline in the Northwest Territories, about 100 kilometers (60 miles) south of the Arctic Circle.

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