Arctic warming threatens polar bears, U.N. told ENN
Tuesday, November 3, 1998
The retreat of the sea ice also means that more bears
may become trapped on or near shore in the summer and
fall, and are more likely to run afoul of humans and
garbage dumps.
At the onset of United Nations climate talks Monday, Greenpeace warned that the impacts of global warming are already appearing and endangering species living in the Arctic -- especially polar bears.
The melting and retreat of Arctic sea ice has already had an affect on polar bear habitat and may ultimately contribute to the extinction of the species, the group says.
Scientists studying Arctic sea ice have recently documented significant changes there and say the Arctic is warming at least twice as fast as the rest of the globe, says Greenpeace. The Nansen Environmental and Remote Sensing Center in Norway found a 4.6 percent decline in ice extent and a 5.8 percent decline in actual ice area between 1978 and 1994.
Polar bears feed nearly exclusively on ringed seals which they hunt from the ice edge or through the pack ice itself. The bears do not catch the seals in the water, but wait at holes for them to come through the ice to breathe.
The retreat of the sea ice also means that more bears may become trapped on or near shore in the summer and fall, and are more likely to run afoul of humans and garbage dumps, or in the case of Alaska, with the industrial complex associated with oil development on Alaska's North Slope. In these encounters, the bears usually lose.
"If they lose their ice platform, we lose their habitat, and we're not going to have any polar bears", said Dr. Charles Jonkel of the U.S.-based Great Bear Foundation.
During a recent expedition to study wildlife populations, Greenpeace's icebreaker, m/v Arctic Sunrise, carried scientists and campaigners to the 'ice edge' in the Chukchi Sea, that part of the Arctic Ocean between northern Alaska and Russia's Chukotka Peninsula. Normally at or near the coast of Alaska, the ship had to sail more than 150 miles north to find the edge of the ice.
"There certainly seems to be genuine increase in temperature, and I think the temperatures are indicating that something's going on, " said University of Alaska Fairbanks Researcher Lori Quakenbush, who joined the Greenpeace expedition. "There are two things that can affect polar bears: one is a change in the number of ringed seals for them to feed on and the other is a change in the accessibility of those seals. The ice plays a big role in both of those things.
"The food chain in the Arctic is short. The algae that grows on the bottom of the ice is eaten by zooplankton, which is eaten by Arctic cod, which are eaten by ringed seals, which are eaten by the polar bears, and that's about as simple as a food chain gets. A change in the environment can affect anything along the chain," said Quakenbush.
Scientists aboard the Arctic Sunrise were surprised by how far north the ice edge had retreated. However, this fits with the findings of a recent joint Canadian/American expedition where scientists were frozen into the Arctic ice pack aboard a Canadian icebreaker north of Alaska for more than a year. Scientists found the ice to be much thinner (1.5 meters at most, rather than the 2-3 meters that would be expected), and much warmer and less salty due to recent melting of the pack.
Greenpeace's Arctic Expedition leader Steve Sawyer said, "The delegates in Buenos Aires have to be reminded that climate change is not something which will happen in the future, it is happening now, most dramatically in the Arctic. The main cause is clear and undisputed. Increased carbon dioxide in the atmosphere due to the burning of fossil fuels is accepted as the main cause of climate change by all scientists save those working for the fossil fuel industry. Polar bears may be some of the earliest victims, but the rest of us are not far behind."
http://www.enn.com/news/enn-stories/1998/11/110398/polarbear.asp
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