In September 2016, during NASA's Ocean Melting Greenland Field Mission, a southeastern Greenland polar bear foraged on a glacier at 61 degrees north latitude
On June 16, 2022, a NASA-funded study reported in the journal Science that Greenland's fjords are home to a unique group of polar bears that rely on glacial ice.
Polar bears throughout the Arctic rely on sea ice as a platform for catching seals. As climate change warms the planet and Arctic sea ice melts, polar bears are struggling to find ice to hunt for. In southeastern Greenland, however, scientists have found that polar bears survive in fjords for most of the year, relying on ice mixtures, a mixture of sea ice and glacial ice cubes cut by the glaciers of the ocean. This group of polar bears has been isolated from polar bears for hundreds of years and has found that they are genetically different.
Satellite tracking shows that southeastern polar bears and northeastern polar bears have different populations and behave differently.
The tan area indicates that the polar bears of northeast Greenland hunt across vast expanses of sea ice. Purple areas indicate that the southeastern Greenland polar bear has more limited activity in its home fjords or adjacent fjords.
An international team of scientists, including scientists from the University of Washington and the National Ice and Snow and Data Center (NSIDC), tracked bears in southeastern Greenland for seven years and combined their new data with genetic analysis and 30 years of historical data from the entire region of Greenland. They also used medium-resolution imaginary spectroradiometer instruments (MODIS) and NSIDC data on NASA's Terra and Aqua satellites to record fjord and offshore sea ice environments.
The findings suggest that southeastern Greenland bears are isolated from sea ice two-thirds of the year and supplement their food by using freshwater ice plates, which often fall off the Greenland ice sheet and coastal glaciers. Bears also travel between fjords through inland ice and hiking over mountains.
Shown here is the Tingmiarmiut Fjord in southeastern Greenland's polar bear population habitat, in early spring. The image was collected on April 6, 2022.
Due to climate change, this group of genetically distinct polar bears use strategies that could help the species survive in a warming world. But the researchers warn that glacial ice cannot provide habitat for many bears because relatively few places throw large amounts of glacial ice into the ocean. In much of the Arctic, polar bear populations are likely to decrease because they are completely dependent on sea ice.
Shown here is the Tingmiarmiut Fjord in the summer polar bear habitat of southeastern Greenland. This image was acquired on August 8, 2021.
The white dot in the black water is floating glacial ice that has fallen off the central glacier of Heimdall and other glaciers in the fjord, which bears use instead of sea ice to hunt.
Co-author and NSIDC deputy chief scientist Twila Moon said this collaboration was important to support the team's interdisciplinary research. "We believe these cross-collaborations are critical to addressing many of the pressing research challenges associated with our rapidly changing world," she added.