ANCHORAGE, ALASKA — As federal marine mammal experts in Alaska scramble to study how global warming will affect walrus, polar bears and ice seals, they warn there are limit to the protections they can provide.
They can restrict hunters, ship traffic and offshore petroleum activity, but they acknowledge there are limits if the animals' basic habitat -- sea ice -- disappears every summer.
"Ultimately it's beyond my scope," said Joel Garlich-Miller, a walrus expert for the U.S. Fish and Wildlife Service in Anchorage. "I can't make ice cubes out there."
Garlich-Miller spoke after confirming that 3,000 to 4,000 mostly young walrus died this year in stampedes on land on the Russian side of the Chukchi Sea, the body of water touching Alaska and Russia just north of the Bering Strait. Instead of spending the summer spread over sea ice, thousands of walrus were stranded on land in unprecedented numbers for up to three months.
If current ice trends continue, and walrus are based on coastlines every summer, they will put tremendous pressure on nearby foraging areas rather than on rich offshore feeding areas -- sort of like putting all the cattle from a farm into one small pasture, said Tony Fischbach of the U.S. Geological Survey.
Experts on summer sea ice say it's not likely to suddenly reappear. Arctic sea ice this summer plummeted to the lowest levels since satellite measurements began in 1979, according to the National Snow and Ice Data Center at the University of Colorado.
"Certainly we look like we're on a death spiral right now," said Mark Serreze, senior research scientist. "Losing that summer sea ice-over by 2030, within some of our lifetimes, is a reasonable expectation."
Sea ice loss could have a devastating effect. The U.S. Fish and Wildlife Service within weeks will decide whether to list polar bears as "threatened" under the federal Endangered Species Act because of the loss of sea ice from global warming. Polar bears hunt and breed on sea ice and are poor candidates for survival if they are based on land, where grizzly bears dominate.
Polar bears' primary prey are ringed seals, as many as 43 per year. They're the only seals that thrive under sea ice, digging breathing holes with their thick claws and creating lairs on top of the ice where they birth their young. With warming, those lairs collapse earlier in springtime, leaving hairless pups susceptible to freezing, foxes, polar bears and even ravens and gulls.
