Scientists have discovered a new population of polar bears in Greenland, raising the possibility that at least a few representatives of this species may survive this century. The Arctic sea ice should indeed end up completely disappearing.
The rapid melting of sea ice in the Arctic poses a serious threat to the survival of polar bears, which use it as a platform to hunt seals.
But scientists have identified a new population of polar bears in southeast Greenland, which uses chunks of ice breaking off from freshwater glaciers in the region.
Where will they be able to stay?
Their discovery, described in a study published Thursday in the prestigious journal Scienceopens the possibility that at least a few representatives of this species could survive during the century, knowing that the Arctic sea ice should eventually completely disappear in summer.
“One of the big questions is where the polar bears are going to be able to stay,” Kristin Laidre, a scientist at the University of Washington and the Greenland Institute of Natural Resources, told AFP. “I think bears roaming around in a place like that can teach us a lot about where that might be.”
She and her colleagues first spent two years interviewing Inuit hunters. Then they began their fieldwork, conducted between 2015 and 2021, in an understudied region due to its unpredictable weather, heavy snowfall and mountains.
“The most genetically isolated population of polar bears on the planet”
Each year, the researchers spent a month there, in the spring, staying as close as possible to the place of life of these polar bears, two hours away by helicopter. Reserves of fuel had to be placed on the road in advance.
This population has a priori several hundred individuals. Bears were fitted with satellite tracking devices, and DNA samples were collected, either by capturing some of them or using darts to take biopsies.
“This is the most genetically isolated population of polar bears on the planet,” said study co-author Beth Shapiro, a geneticist at the University of California, Santa Cruz. “We know that this population lived separately from other polar bears for at least several hundred years.”
Unlike their cousins, these polar bears are more of a homebody, and don’t go far to hunt. Their isolation stems from the geography of where they live: a complex landscape of fjords on the southern tip of Greenland, well below the Arctic Circle, with nowhere to go. To the west, impressive mountains, and to the east, the waters of the Denmark Strait, with a rapid current along the coasts, in a southerly direction.
“When they get swept away by this current, they jump off the ice and walk back to their fjords,” explained Kristin Laidre. According to the researchers, some bears had to travel more than 150 kilometers to return home.
While sea ice (seawater) provides a hunting platform for most of the approximately 26,000 polar bears in the Arctic, in southeast Greenland polar bears only have access to it for four months, between February and the end of May. During the other eight months, they rely on pieces of freshwater ice breaking away from glaciers and ending up directly in the sea.
“The combination of fjords, high ice production, and the large reservoir of ice from the Greenland Ice Sheet is what currently provides a continuous supply of ice from glaciers,” Twila Moon, co-author, said in a statement. author of the study.
Much remains to be studied in the polar bears of this part of Greenland. Measurements have shown that adult females are somewhat smaller than average, and they seem to have fewer young. But it is difficult to draw conclusions in the absence of long-term data.
Kristin Laidre warns that we must beware of placing too many hopes in this study. Polar bears – iconic animals in their own right, but also a precious resource for the people of the region – will not be saved without urgent action to combat climate change.
But this population may have a better chance of survival than the others. And other regions of Greenland have glaciers ending directly in the sea. They could, in the future, become small climatic refuges.