According to the new study, published in the Earth’s Future journal, if carbon emissions remain at current levels, the summer ice will completely disappear by 2100.
The shrinkage of the Arctic summer sea ice could lead to the disappearance of polar bears and seals by 2100, a new study has warned.
The shrinking summer sea ice has been a long-term concern as species depend on it for their survival. According to the new study, published in the Earth’s Future journal, if carbon emissions remain at current levels, the summer ice will completely disappear by 2100.
Ice and life
Most of the Arctic Ocean surface freezes in winter and scientists see this continuing for the foreseeable future, even if the climate warms. When the ice melts in the summer, currents and wind carry it great distances — even into the North Atlantic, but often into the far reaches of the Arctic, along the Canadian and Greenland islands.
This creates a marine ecosystem. The algae that bloom on the Arctic ice feed tiny animals. Fish, in turn, feed on these animals, seals feed on the fish, while polar bears, which sit at the top of the food chain, then feed on the seals. The irregular topography also helps seals set up lairs, while the polar bears reside in the ice caves during the winter.
However, with the climate warming, the summer sea ice is fast shrinking and now has an acreage less than half it had in the early 1980s.
The study covered a massive 1 million-sq km region north of Canadian Archipelago coasts and Greenland. Sea ice has traditionally been thickest all year round in this region and, thus, most resilient.
The researchers looked at two scenarios — optimistic (if carbon emissions checked) and pessimistic (if emissions continue). Summer ice in the region will dramatically thin by 2050. Under the study’s optimistic scenario, some summer ice could indefinitely persist. Under the pessimistic scenario, however, the summer ice would disappear completely by the end of the century.
Under the low-emissions or optimistic scenario, ice from the central Arctic will also disappear by the middle of the century. Locally formed summer ice will continue to persist in the Last Ice Area, but will only be a metre thick.
The study forecasts that some polar bears, seals, and other creatures could survive under the low-emissions scenario. These species exist under similar summer conditions along parts of Hudson Bay and western Alaska.
However, under the higher-emissions scenario, even the locally formed ice will completely disappear in the summers by 2100. With no summer ice, ice-dependent ecosystems will perish.
Senior Research Scientist Robert Newton, who co-authored the study, told Columbia University’s Climate School that if the year-round ice went away, ice-dependent ecosystems would completely collapse, and something new would begin.
He added that new things would emerge, but it might take the new creatures some time to invade.
Newton said fish and algae might swim up from the North Atlantic, but it was unclear if they could survive year-round.