A polar bear mother and her two cubs walk along the shore of Hudson Bay near Churchill, Man., in 2007. (Jonathan Hayward/Canadian Press)

Canada joined four other Arctic countries in declaring climate change the single greatest threat to polar bears, a move that could pressure the government to take further action to curb global warming.

Canada, Denmark, Norway, Russia and the United States made the declaration after a three-day meeting week in the Norwegian town of Tromsoe, a month before a meeting of the Arctic Council in the same town.

"The parties agreed that long-term conservation of polar bears depends upon successful mitigation of climate change," the countries said in a joint statement.

The Agreement on the Conservation of Polar Bears was primarily concerned with protecting polar bears from hunting when it was first signed in 1973. But four decades later, the countries agreed "that impacts of climate change and the continued and increasing loss and fragmentation of sea ice … constitute the most important threat to polar bear conservation."

Conservation group World Wildlife Fund applauded the agreement, and said it should drive Canada to take further steps to address climate change.

"Canada, with two-thirds of the world's polar bears, has a special duty to help solve the climate crisis," said WWF Canada director of species conservation Peter Ewins in a statement, saying Minister of Environment Jim Prentice will now be the focus of international attention.

"Finally, it now seems that minister has reluctantly agreed that climate change is affecting polar bear habitat, the first step in taking strong action to protect it," he said.

In addition to identifying the threat of sea ice loss as a result of climate change, Canada also agreed to monitor and control industrial development in polar bear habitats.

The agreement stopped short of making a direct appeal for action to the United Nations climate conference, scheduled to take place in Copenhagen in December 2009, where countries will plan to negotiate a treaty to replace the Kyoto Protocol, which expires in 2012.

The next meeting of the five countries on the status of polar bears will take place in Canada in 2011, followed by one in Russia in 2013.

With files from the Associated Press