Wildlife and Global Warming - Navigating the Arctic Meltdown
Walruses Food or rest—which to give up? This is the harsh choice faced by walruses as global warming accelerates melting of Arctic sea ice and lengthens the distance between shallow-water feeding grounds and ice floes where the animals haul out to rest and give birth. Newborn walrus calves must remain on the ice, safe from predation by orca whales, while their mothers shuttle between nursing the young and foraging on the sea-bottom. As climate change impacts shrink the sea ice pack, it puts the newborns’ safe haven farther away from the mothers’ food—meaning long, exhausting swims for the mothers, and more time alone for the calves.
In the summer of 2004, as the sea ice dwindled, shipboard researchers in the Beaufort Sea off the coast of Alaska encountered one of the starkest consequences of global warming: walrus calves abandoned by mothers that had returned to shallows, now far from ice, to feed. The nine calves spotted near the retreating ice were in water 3,000 feet deep—five times deeper than a walrus can dive. “We were [there] for 24 hours, and the calves would be swimming around us and crying,” said Carin Ashjian, a biologist from Woods Hole Oceanographic Institution on the research expedition.