The last refuge in the Arctic for polar bears, walruses and seals is more vulnerable to climate change than previously thought after the unexpected and dramatic loss of sea ice, a new report says.
Last year, large areas of open water appeared in the Wandel Sea, part of what is known as the “Last Ice Area” north of Greenland, after unusual summer winds and thinning ice led to rapid melting, according to an article published in Communications Earth & Environment.
Sea ice circulates through the Arctic and naturally ends up piling against Greenland and the northern Canadian coast, covering the area with thick and compact ice. Climate models suggest that the area will last longer than anywhere else as global temperatures rise.
Experts believe that the area would be the last refuge for mammals that rely on the ice to rest and breed as the planet warms. But the melt – contrary to the predictions of climate experts - has raised more immediate concerns for their survival.
The sea ice is key for three main species. Seals build dens for their young on the ice, who are in turn hunted by polar bears. Walruses use the ice as a base for foraging.
Polar bears, currently listed as vulnerable on the international database recording the health of species, rely on the sea ice for hunting, resting and mating. But the bears are spending increasing amounts of time on land owing to the receding ice, resulting in more contact with humans.
“We know very little about marine mammals in the Last Ice Area,” said Kristin Laidre, a co-author of the study from the University of Washington. “We have almost no historical or present-day data, and the reality is that there are a lot more questions than answers about the future of these populations.”
Researchers used satellite images and data collected since 1979 to suggest that climate change had contributed to long-term thinning of the ice. But the greatest reason for the ice loss was strong summer winds during an unusual period of weather than blew ice away from the area, they said.
“Current thinking is that this area may be the last refuge for ice-dependent species,” said polar scientist Axel Schweiger, who led the study. “So if, as our study shows, it may be more vulnerable to climate change than people have been assuming, that’s important.”