Decades of climate data have demonstrated conclusively that the Arctic ice sheet is rapidly melting away. Less attention has been paid to the effect global warming will have on neighboring near-Arctic ecosystems, but a new study published in the journal Science reports that these regions are just as endangered.
The study, conducted by a multi-disciplinary group of researchers from the US and Canada, found that the Bering Sea is warming at a rate that's causing major changes in its marine ecosystem, a trend that makes it an excellent model for the rest of the world's waterways.
"Really what we're seeing is a fundamental shift in the food web," said Lee Cooper, a marine biologist at the University of Tennessee . "Probably what's going to happen is that fish and other animals in the southern Bering Sea will be moving north, reproducing and competing with animals that live there now."
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As the Bering Sea heats up, the amount of sea ice coverage decreases, causing problems for walruses that rest on broken ice floes and the sea algae that grows on its underside.
"We have indications of a couple degree warming on the bottom," said Jacqueline Grebmeier, a University of Tennessee research professor at and the study's coauthor. "On the surface, between 2002 and 2004, there was about a four degree difference in surface water temperature."
To determine just what effects the warming ocean was having on regional wildlife, the team pored over previous studies and anecdotal records to compile the first overview of the ecological damage being done to the Bering.
"We wanted to get data from several different fields: atmospheric data, fisheries data, anecdotal data from the Yupik people who live there, as well as biological data taken every year and remote sensing data," said Cooper.
They found, as they expected, that the warming of the ocean is causing fish, crabs, grey whales, clams and birds from the sub-arctic Southern Bering to migrate steadily north, encroaching on the wildlife that lives around the Sea's northern edge.
The inhabitants of the Bering Sea Islands have also suffered from the melting sea ice. Yupik peoples living on Big and Little Diomede used to build a runway on the thick winter ice between their islands in order to have supplies flown in, but the warmer water has made this impossible. A reliable ice sheet is also vital for the Yupik's subsistence hunting of walruses and other animals.
"There's been a big change in sea ice coverage, and it's making hunting success less predictable and more dangerous," said Cooper. "People are being lost and there's no Coast Guard presence or anything like that up there."
But the warming of the Bering Sea affects more than just the people living there. Because of the water's shallowness—it's among the largest continental shelves in the world—the Bering Sea takes less energy to warm up than deeper waters like the North Pacific. This responsiveness makes it an excellent indicator of what could happen in larger bodies of water as the Earth continues to heat.