Over the years, the plight of polar bears has become highly politicized. Groups such as the Cato Institute, a libertarian research organization that questions aspects of climate change, have raised concerns about exaggerated bears, arguing that some research shows the animals have survived repeated hot spells. But scientists say that during previous warm periods, bears probably had other important food sources, including whales, which they do not have today.
Poignant images of bears on isolated ice or foraging for food have been used by conservation groups and others to show the need to act to reduce global warming. Sometimes, however, it has been shown that these images are not what they appear.
After a video of an emaciated bear picking up trash in the Canadian Arctic was posted online by National Geographic in 2017, the magazine acknowledged that the bear’s condition may not have been linked to the climate change. Scientists had pointed out that there was no way to know what was wrong with the bear; it might have been sick or very old.
The new study did not include projections in which emissions were reduced drastically, said Cecilia M. Bitz, atmospheric scientist at the University of Washington and author of the study. Researchers had to be able to determine, as precisely as possible, the periods when sea ice would disappear from a particular region. “If we had wanted to examine many models, we would not have been able to do so,” said Dr. Bitz.
Andrew Derocher, a polar bear researcher at the University of Alberta who was not involved in the study, said the results “are very consistent with what we are seeing from empirical studies like monitoring field work ”.
“The study clearly shows that polar bears will do better with less warming,” he added. “But whatever scenario you envision, there are serious concerns about the conservation of the species. “
Of the 19 subpopulations, little is known about some of them, especially those in the Russian Arctic. Among the subpopulations studied, some – generally those from regions with less ice loss – have so far experienced a small population decline. But others, particularly in the southern Beaufort Sea off northeast Alaska and western Hudson Bay in Canada, have been severely affected by the loss of sea ice.