Breezy Explainer: Glacial ice could be a lifeline for polar bears as ice melts

Most polar bears depend upon the ice in the sea to survive. However, scientists discovered that those in Southeast Greenland are using glacial ice as hunting platforms and habitats. Here is more on the extraordinary step.

A new subpopulation of polar bears survive on glacial ice

Change is the only constant. But, Kristin Laidre did not expect to discover a new sub-population when she started working on a long-term project to study them. Moreover, she did not expect to find the most genetically isolated polar bears. Genetic isolation is a population of a species having little mixing with others of their species. In the end, this leads to the formation of a new species. Currently, there are 19 recognized subpopulations of polar bears throughout the Arctic region.

The group found a group of several hundred polar bears that are genetically and behaviorally unique. This is because sea ice is important to polar bears for hunting seals. However, those in southeast Greenland came up with another way. They are using glacial ice. Glacial ice is pieces of ice that break away from glaciers.

“We were not expecting to identify a unique group as we found in the southeast,” stated Laidre. She is a polar bear expert from the Greenland Institute of Natural Resources and the University of Washington.

Climate change: A common threat

As per the report published by the group in Science, glacial ice or “marine-terminating glaciers,” may serve as “previously unrecognized climate refugia”. This shows how polar bears might be successful in surviving the warming temperatures that come with climate change. “As a glaciologist, I had not previously thought of glacial ice as important habitat for polar bears,” stated Twila Moon. Moon is a climate scientist from the University of Colorado and a co-author of the study. 

“In the southeast part of Greenland, sea ice is relatively scarce, materializing for less than 100 days per year. Comparatively, a polar bear’s seasonal fasting period usually lasts between 100 and 180 days,” reveals the study. Marine-terminating glaciers are present in pockets around the Arctic. But, glaciers in Greenland produce a large amount of glacial ice. “They are fed by the large reservoir of ice contained in Greenland. Even in a trajectory of continued warming and ice loss, the glaciers in the southeast section of Greenland are not expected to retreat as quickly as the ice in other parts of the country,” added Moon.

Owing to the reduction of sea ice, polar bears may move from vulnerable to extinct. According to another study, they could disappear by 2100 if the world continues warming. “There are limited locations in the Arctic where this type of glacial ice environment is available, so we still expect to see large declines in polar bears across the Arctic as sea ice continues to diminish under climate change,” stated Laidre. According to her, further studies may also reveal bear populations in the ice-free Arctic.