Scientists who studied and tracked the bears found that they survive despite having limited access to sea ice – something vital for polar bears – and instead use the freshwater ice supplied by Greenland’s ice sheet.
“We wanted to study this region because we didn’t know much about the polar bears in Southeast Greenland, but we never expected to find a new subpopulation there,” said the study’s lead author Kristin Laidre, a polar researcher at the University of Greenland Washingtons Applied Physics Laboratory, in a statement.
“We knew from historical records and indigenous knowledge that there are some bears in the area. We just didn’t realize how special they were.”
An icy necessity
The 19 known polar bear populations that travel widely rely on sea ice to hunt their prey, like ringed seals, and sit near breathing holes to capture their prey. The calories provided by seals can help them store energy for months when food and sea ice become scarce.
Global warming is rapidly melting and disappearing sea ice as the Arctic warms more than twice as fast as the rest of the planet. As the sea ice disappears, polar bears will have to move onto land, giving them fewer food options.
Meanwhile, south-east Greenland polar bears tend to stay close to home, so they have adapted to their environment in unique ways. Despite being isolated due to the Greenland ice sheet, mountains, open water, and fast-flowing coastal currents, the polar bears have access to freshwater ice and limited access to sea ice, which helps them capture seals.
The bears can use sea ice between February and the end of May. The rest of the year they hunt seals, using the freshwater ice as it breaks away from the ice sheet.
“Polar bears are threatened by the loss of sea ice due to climate change. This new population gives us a glimpse of how the species might survive in the future,” said Laidre, also an associate professor of aquatic and fisheries sciences at the University of Washington.
“But we have to be careful when extrapolating our results, because the glacial ice that allows southeast Greenland bears to survive is not available in most parts of the Arctic.”
The environment of southeast Greenland is a unique, small climate haven in which the bears can survive, and similar habitats are found along the Greenland coast and the Norwegian island of Svalbard.
“These types of glaciers are found elsewhere in the Arctic, but the combination of fjord shapes, the high production of glacial ice and the very large ice reservoir available from the Greenland ice sheet currently provides a constant supply of glacial ice,” she said Study co-author Twila Moon, associate senior scientist at the US National Snow and Ice Data Center in Boulder, Colorado, in a statement.
“In a way, these bears provide insight into how Greenland’s bears might fare under future climate scenarios,” Laidre said. “Sea ice conditions in Southeast Greenland today are similar to those predicted for Northeast Greenland later this century.”
The new study consists of 30 years of historical data from Greenland’s east coast and seven years of new data from the southeast coast. The latter is a remote region with sharp mountains, heavy snowfall and unpredictable weather, making study difficult.
The research team spent two years consulting with polar bear hunters, who hunt for survival rather than sport in East Greenland. The hunters could share their expertise and contribute samples for genetic analysis.
The researchers, working with the Greenland Institute of Natural Resources in Nuuk, Greenland, were able to use helicopters to study and track the bears while the researchers flew over sea ice, and estimated that a few hundred bears live in the remote area. This is similar to other small populations of polar bears elsewhere.
Female polar bears in Southeast Greenland are smaller than female polar bears in other regions. The smaller bears also have fewer cubs, which could be related to trying to find mates while touring the surrounding fjords and mountains. But researchers won’t know for sure until they have more data from long-term monitoring of the bears.
The bears either travel across ice within fjords or climb over mountains to reach neighboring fjords. Of the 27 bears tracked during the study, half accidentally drifted an average of about 120 miles (190 kilometers) south and got stuck on small ice floes caught in East Greenland’s strong coastal currents.
As soon as the bears had a chance, they would just jump off the ice and hike back to the fjord they call home. Created by glaciers, fjords are long, narrow deep-sea bays nestled between high cliffs.
“Even though the ice sheet is changing rapidly, this area of Greenland has the potential to produce glacial ice for a long time to come, with a coastline that could resemble today’s,” Moon said.
However, the researchers warn that this habitat may not be enough for other polar bears suffering from the climate crisis.
“If you’re concerned about the conservation of the species, then yes, our results are hopeful — I think they show us how some polar bears might survive under climate change,” Laidre said.
“But I don’t think the glacier habitat will support large numbers of polar bears. There just isn’t enough of it. We still expect a large decline in polar bears across the Arctic under climate change.”
The researchers believe that polar bears in south-east Greenland evolved in isolation over several hundred years. The earliest known reference to bears at this site dates from the 13th century, and the first written record of the animals in the region’s fjords dates from the 1830s, according to the study’s authors.
The status of the polar bears remains unknown. Researchers don’t know if the population is stable, increasing, or declining, but closer monitoring could reveal what the future holds for this unique population, Laidre said.
Due to their isolation, polar bears are so genetically diverse that the researchers propose to consider the polar bears of south-eastern Greenland as the 20th subpopulation of the species.
Ultimately, that decision rests with the International Union for the Conservation of Nature, which helps monitor protected species. And the Greenlandic government will make all decisions to protect the bears.
“Conserving polar bear genetic diversity is critical for the future in the face of climate change,” Laidre said. “Official recognition of these bears as a separate population will be important for conservation and management.”
Meanwhile, sea ice in the Arctic continues to decrease, severely reducing future survival rates for most polar bear populations.
“Climate protection is the most important thing for the future of polar bears,” said Laidre.