Study: Warming threatens polar bear births

EDMONTON, Alberta, Feb. 8 (UPI) -- Polar bear births could plummet with climate change, say Canadian researchers whose studies have linked declining litter sizes with loss of sea ice.

University of Alberta researchers studying polar bears in Hudson Bay say projected reductions in the number of newborn cubs is a significant threat to the region's polar bear population, a university release said Tuesday.

If climate change continues unabated, the viability of the species across much of the arctic could be threatened, the researchers say.

The decreasing length of time Hudson Bay is frozen over, which determines the duration of the polar bear's hunting season, makes it difficult for pregnant females to support themselves, let alone give birth and raise cubs, they say.

In the early 1990s, researchers estimate, 28 percent of energy-deprived female polar bears in the Hudson Bay region failed to have a single cub.

The polar bear population of western Hudson Bay is estimated to be around 900, down from 1,200 bears 10 years ago.

Because the polar bears of Hudson Bay are the most southerly population of all arctic polar bears, they are the first to be affected by the global-warming trend, the researchers say.