Polar Bear Populations Decline in Greenland Over 20,000 Years Due to Climate Change

A comprehensive international study, including researchers from the University of Copenhagen, reveals a concerning decline in polar bear numbers in Greenland over the last 20,000 years. The research, combining genetic analysis, food habits, habitat study, and historical climate data, points to rising sea temperatures as the key driver behind this decline.
The study, published in Science Advances, emphasizes the impact of global warming, leading to increased sea temperatures and reduced sea ice, consequently affecting the polar bear‘s primary food source – seals. Michael Westbury, lead author and assistant professor at the University of Copenhagen, highlights the non-linear relationship, where even small environmental changes significantly impact polar bear populations.

The research indicates that a 0.2 to 0.5 degrees Celsius rise in sea temperatures over 20,000 years resulted in a 20 to 40 per cent reduction in the polar bear population. The current rate of temperature increase, attributed to ongoing global warming, is unprecedented compared to historical trends.
Eline Lorenzen, a professor at the University of Copenhagen, warns of a potential 2 to 5 degrees Celsius increase in sea temperatures around Greenland in the future, a tenfold rise compared to the last 20,000 years. This grim outlook raises concerns about the survival of the polar bear population, given their role as ecosystem indicators in the Arctic.
The study suggests that polar bears exhibit dietary flexibility, adjusting their food choices in response to changing conditions. In East Greenland, male and female polar bears differentiate their dietary preferences, a strategy to avoid competition for resources when facing scarcity.
As climate change accelerates, these findings underscore the urgent need for conservation efforts and proactive measures to address the challenges faced by polar bears in adapting to their changing environment. The study not only highlights the vulnerability of polar bears but also emphasizes the broader ecosystem changes occurring in the Arctic due to climate pressures.