Researchers led by professor Andrew Derocher from the University of Alberta said that one very bad ice year could leave hundreds of Hudson Bay polar bears stranded on land for an extended period.
They also said one unexpected jump in Arctic warming trends could send some polar bear populations into a precipitous decline.
"It's a fact that early sea ice breakup, late ice freeze-up and the overall reduction in ice pack are taking their toll," said Derocher.
"We want governments to be ready with conservation and management plans for polar bears when a worst-case climate change scenario happens," Derocher said in a statement.
The effects of climate change on polar bears are clear from both observational and modelling studies in many areas where the bears are found, researchers said.
Earlier studies by Derocher and his colleagues show that one very bad ice year could leave hundreds of Hudson Bay polar bears stranded on land for an extended period.
"Such an event could erase half of a population in a single year," Derocher noted.
Derocher and 11 other international scientists, who have co-authored the policy perspective study, urged governments to start planning for rapid Arctic ecosystem change to deal with a climate change catastrophe for the animal.
"Around the world, polar bears are an iconic symbol, so any tragedy would produce massive attention. If the warming trend around Hudson Bay took an upward spike, the population of 900 to 1,000 bears in western Hudson Bay would be on the line, so there has to be a plan," said Derocher.
The study was published in the journal Conservation Letters.
