A major international report says the increasingly rapid loss of Arctic sea ice is already taking a toll on polar bears and Canada should reconsider its decision not to include the predators on its list of endangered species.
The Polar Bear Specialist Group, which met over the weekend in Copenhagen, Denmark, has concluded that the overall condition of the world’s 19 polar bear populations is deteriorating. The group is part of the International Union for the Conservation of Nature, one of the world’s largest environmental science networks.
The group says that the number of bear populations in decline is eight — up from five in its last report in 2005. Three populations are considered stable compared with five previously.
Only one population is increasing. Information on seven populations is still too scarce to draw conclusions.
The report released Monday suggests an “unprecedented” loss in sea ice, which bears use as a seal-hunting platform, is behind the trend.
Group chairman Erik Born points to evidence from around Churchill, Man., where sea ice is now breaking up about three weeks earlier than it used to.
“They’ve been weighing and measuring polar bears and they’ve been able to demonstrate there is a clear downward trend in the body mass of adult females,” Born said from Copenhagen. “There is also evidence (of) decreased survival of very old bears and younger bears which can be linked to the change in sea ice.”
Born, a biologist from the Greenland Institute of Natural Resources, said evidence suggests the same story is playing out across the Arctic.
“It’s a pretty good correlation that this is what will happen in other polar bear populations that suffer from decrease in sea ice. I think it’s fair to assume that this is what will happen in other places.”
Sea ice reached a record low in 2007 and is also well below average this summer. A study released last week found that the extent of ice cover averaged less in the 20th century than in any time during the last 800 years.
Nor is disappearing sea ice the only threat the bears face.
The report found rising levels of mercury, a potent neurotoxin, in bear bodies. As well, at least one population — the Baffin Bay bears of Canada and Greenland — is probably being overhunted, although Inuit hunters in that area have long disputed that.