Scientists expected the opposite, but polar bears in the Norwegian Arctic archipelago of Svalbard have become fatter and healthier since the early 1990s, all while sea ice has steadily declined due to climate change. Polar bears rely on sea ice as a platform from which to hunt the seals that they rely on for blubber-rich meals. The bears' fat reserves provide energy and insulation and allow mothers to produce rich milk for cubs. Researchers weighed and measured 770 adults in Svalbard between 1992 and 2019 and found that bears had become significantly fatter. They think that Svalbard bears have adapted to recent ice loss by eating more land-based prey, including reindeer and walruses.
The discovery, published in Scientific Reports, was particularly puzzling because of the impact of climate change in Svalbard. During the same period that this research was carried out, global temperature rise has reduced the number of ice-free days per year in the region by almost 100 - at a rate of about four days each year. Lead researcher Dr. Jon Aars from the Norwegian Polar Institute explained that the fatter a bear is, the better it is, and he would have expected to see a decline in body condition given the loss of sea ice.
Experts suggest that the increase in walrus populations, due to protections since the 1950s, provides a vital food source for polar bears. If seals condense into smaller areas of ice, they may be easier for the bears to hunt. Despite the current positive outlook, researchers warn that continued ice loss will ultimately threaten the bears' survival, as they will have to travel further for food, depleting their fat reserves in the process. The study implies a temporary boost for the bears owing to a recovering population and increased prey availability, but the long-term perspective remains grim due to the inevitable impacts of climate change.
The discovery, published in Scientific Reports, was particularly puzzling because of the impact of climate change in Svalbard. During the same period that this research was carried out, global temperature rise has reduced the number of ice-free days per year in the region by almost 100 - at a rate of about four days each year. Lead researcher Dr. Jon Aars from the Norwegian Polar Institute explained that the fatter a bear is, the better it is, and he would have expected to see a decline in body condition given the loss of sea ice.
Experts suggest that the increase in walrus populations, due to protections since the 1950s, provides a vital food source for polar bears. If seals condense into smaller areas of ice, they may be easier for the bears to hunt. Despite the current positive outlook, researchers warn that continued ice loss will ultimately threaten the bears' survival, as they will have to travel further for food, depleting their fat reserves in the process. The study implies a temporary boost for the bears owing to a recovering population and increased prey availability, but the long-term perspective remains grim due to the inevitable impacts of climate change.
