US EPA

2158490 

Journal Article 

Polar bear numbers set to fall 

Courtland, R 

2008 

1 

Nature
ISSN: 0028-0836
EISSN: 1476-4687 

453 

7194 

432-433 

English 

18497777 

10.1038/453432a 

WOS:000256023700004 

The polar bear, Ursus maritimus has been declared a threatened species. The continuing retreat in Arctic sea ice due to global warming is connected with large potential reductions in the polar- bear population. Polar bears range across a variety of nations, each with its own conservation approaches, and a variety of habitats, each of which will be affected differently by climate change. Factors other than global warming compound stress on the bears, including the accumulation in fat of polychlorinated biphenyls and other pollutants that lower reproductive capacity and weaken the immune system. Bears that spend the majority of their time on ice may have to migrate long distances to maintain their lifestyle, an additional stress if food is scarce. But polar bear populations in the Canadian archipelago may be fairly stable in the next few decades, as projections suggest that summer sea ice there will be more persistent. Polar bear numbers set to fall fattening up on nesting ringed seals. West of Hudson Bay, young bears are less likely to survive after earlier sea-ice break-ups. Some bear populations may be able to adapt by spending more time on land, but much depends on how quickly the Arctic ice changes. Polar bears are likely to remain at the top of the international agenda for the foreseeable future and its management options are being discussed.