Warmer Winters Threaten Polar Bears
Discovery.com,Nov. 4, 2002
Nov. 4 — Polar bears that roam the Hudson Bay area in the great Canadian North are impatiently waiting for ice to form, and as the winter shortens year by year their lives are becoming increasingly threatened.
"Over the last 20 years, the ice breaks an average of two weeks earlier," said Michael Goodyear, director of the Churchill Northern Studies Center.
The giant white bears need the ice to gain access to ringed and barbed seals that live and play away from land among the icebergs.
"For every week a bear has not been ice hunting, it is 10 kilograms pounds) lighter, which can be dangerous as polar bears need to fatten up for the five months in the summer and fall that they are forced to fast," Goodyear said.
The thousand or more polar bear families of the Hudson Bay area are in great danger if, as Goodyear believes, ice disappears from the area by 2050.
"Churchill is one of the best places I see climate change as so important," he said. The average temperature here has risen 0.3 to 0.4 degrees Celsius since 1950. According to the Canadian Wildlife Service the bears, on average, already weigh between 80 and 85 kilograms (176 and 187 pounds) less than they did in 1985.
Goodyear's alarm echoes those of many specialists in the past few years. Ian Stirling is one of the Canadian Wildlife Service's Arctic experts.
In an article for Arctic Magazine three years ago, he noted that between 1981 and 1998 the physical condition of both male and female adult bears had seriously deteriorated in western Hudson Bay bears, in tandem with a general reduction in their numbers.
According to Stirling, the immediate cause of this decline was an increasingly early melt, leading the bears to come ashore in weaker and weaker states. The source of the shortened ice season appeared to be the effect of long-term gradual warming in the spring, he said.
"Polar bears in Hudson Bay are being impacted by climate change," said Lynn Rosentrater, co-author of the World Wildlife Fund's report "Polar Bears at Risk."
"As sea ice is being reduced in the area, the polar bear's basis for survival is being threatened. The sea ice is melting earlier in the spring which is sending polar bears to land earlier without them having developed as much fat reserves for the ice free season," said Rosentrater, who is also the climate change officer at the fund's Arctic Program.
"By the end of the summer they are skinny bears, which in the worst case can affect their ability to reproduce."
In an article in the journal Science from August, Richard Kerr reported: "In western Hudson Bay, where warmer temperatures in the 1990s made for earlier ice melting in the spring and later formation in the fall, polar bears have suffered."