A new study published in Nature Climate Change found that polar bears may be wiped out due to shrinking sea ice in the Arctic

By Eric Todisco
July 21, 2020 11:11 AM
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By the end of the century, polar bears may go extinct as a result of global warming effects on the shrinking sea ice in the Arctic, a new study says.

Peter K. Molnar, a researcher at the University of Toronto Scarborough and lead author of the study, which was published Monday in Nature Climate Change and shared by the New York Times, said that nearly all 19 sub-populations of polar bears will be wiped out should the loss of sea ice force them onto land and away from their food supplies.

Prolonged fasting, as well as reduced nursing of cubs by mothers, would lead to rapid declines in polar bears' reproduction and survival, the study found.

"There is very little chance that polar bears would persist anywhere in the world, except perhaps in the very high Arctic in one small sub-population," said Dr. Molnar.

According to the study, there are about 25,000 polar bears in the Arctic. They rely on sea ice as their main habitat, where they hunt seals by waiting for them to rise out of holes in the ice.

"You need the sea ice to capture your food,” Dr. Molnar said. "There’s not enough food on land to sustain a polar bear population."

Polar Bear
Bertie Gregory/National Geographic Image Collection

In recent decades, the Arctic region has rapidly warmed, and ice extent in summer has declined by about 13 percent compared to the 1981-2010 average, researchers found.

Dr. Molnar and his colleagues calculated that between the polar bears' energy requirements and the climate-model projections of ice-free days to 2100, the animals will be forced to fast longer than they are capable of.

"There’s going to be a time point when you run out of energy,” Dr. Molnar said.

Daniel Zupanc

Research from the study also showed that even under more modest warming projections, in which greenhouse gas emissions peak by 2040 and then begin to decline, many of the polar bear sub-populations will still be wiped out.

“Not only do the bears have to fast for longer and need more energy to get through this, they also have a harder time to accumulate this energy," Dr. Molnar said.