Polar bear discovery in Greenland raises cautious hopes for conservation
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A polar bear stands on a snow-covered iceberg surrounded by fast ice, or sea ice connected to the shore, in southeast Greenland in March 2016. Photo: Kristin Laidre/University of Washington
Scientists have identified a previously unknown group of polar bears in southeast Greenland living in an environment with relatively little sea ice, potentially pointing toward a way to preserve some of the iconic species as Arctic sea ice melts.
Why it matters: The research suggests polar bears can live in a wider variety of conditions than scientists previously thought — and, some scientists say, raises the possibility that some groups of polar bears in select locations could be more resistant to global warming's sweeping changes.
- However, many questions remain to be answered about the newly identified population and its ability to withstand rapid Arctic climate change.
Driving the news: The newly discovered group of polar bears lives among the isolated fjords and glaciers of southeast Greenland.
- Researchers tracked the group — which they say likely contains a few hundred bears — using satellite data and ground-based tracking devices. They published their findings today in the journal Science.
Polar bears typically use sea ice that freezes along the coastlines as their hunting ground to catch seals. But that ice is absent for more than 250 days each year in southeast Greenland.
- During stretches when they don't have access to sea ice, polar bears typically move to land or head to other areas where they can find sea ice.
- But this newly discovered group was able to stay put and keep hunting, relying instead on freshwater ice from glaciers.
The intrigue: The study's authors say the population offers a window into how some animals might fare as climate change continues to transform the Arctic, where temperatures are increasing about three times as fast as the rest of the world.
- "[S]ome polar bears can become established and adapt to this distinctive environment, which, in some areas, may provide a buffer to sea-ice loss," the authors write.
- The newly discovered population could provide a focus for polar bear conservation efforts, similar to how ecologists are seeking out hardier coral species that can better withstand marine heat waves.
But, but, but... The ice these bears rely on is also under threat. It may offer these bears a hunting ground now, because sea ice is disappearing first, but Greenland's glaciers are melting.
- "These bears are subject to the same climate warming as all other polar bears," lead author Kristin Laidre of the University of Washington told Axios in an interview.
- Whether polar bears use sea ice or ice from glaciers, "the general contours of the story are the same — climate change melt and ice retreat," said John Whiteman, chief research scientist at Polar Bears International. Whiteman was not involved in the new study.
- The pace of ice sheet deterioration will determine whether the population of bears "might do better for a little while" or "end up in jeopardy," Whiteman told Axios.
- "These bears can really shed light on our understanding about the species," Laidre said, "And maybe how other similar areas in Greenland and Svalbard might be really critical to the persistence of polar bears as a species when we lose Arctic sea ice."
Zoom in: The group of polar bears is genetically distinct from others in the Arctic, and the researchers propose it be considered a new 20th subpopulation.
- They estimate the polar bears have been genetically isolated for at least 200 years. But because the bears live for 15 to 20 years on average, there have not been enough generations in the subpopulation to determine whether they have genetic adaptations.
- "From a broad perspective, the lifestyle of these polar bears is similar to others: They're eating marine mammal prey and hanging out on ice in the ocean," Whiteman says. The difference lies in the type of ice these bears rely on versus other Arctic populations.
The big picture: As climate change progresses, scientists are trying to get a handle on which species can move to new areas, which can adapt to new conditions and which are at risk of dying out.
- Recent studies have documented physical changes — for example, larger legs and beaks — or shifts in behavior, including the timing of migration and reproduction, in animals as they face the effects of climate change.
- But those changes can come with costs.
What to watch: It's unclear whether the bears' ability to use the ice sheet is unique to this subpopulation, or whether scientists might find other polar bears relying on ice sheets now that they know to look for that behavior.
- The researchers say the group warrants recognition from the International Union for Conservation of Nature as a subpopulation, a move that could impact conservation efforts for the bears and their habitat.
