Polar Bears Are In-Breeding As Climate Change Makes Migration More Difficult

As climate change continues to impact the natural world in surprising and dismaying ways, its true scope is becoming clear.

The incredibly quick climate changes that we are currently witnessing affect not only weather patterns and habitats but the very genetics of vulnerable species.

This is more evident than ever thanks to a study recently published in The Proceedings of The Royal Society B. Titled “Sea ice reduction drives genetic differentiation among Barents Sea polar bears.” The paper explores an unsettling shift in polar bear populations.


The study analyzed over 600 polar bears from four regions of Norway’s Svalbard Archipelago over the course of two decades. The team was looking for changes in genetic data, as well as differences that may exist between sub-populations of polar bears, who are grouped throughout the area and interact during migration.

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The data they compiled shows some disturbing changes. “Our results revealed a 3–10% loss of genetic diversity across the study period,” the authors wrote, explaining that “over time, such erosion of genetic diversity may reduce the fitness of individuals and cause an elevated risk of extinction.”

PHOTO: WIKIMEDIA / Arturo de Frias Marques

This decrease in genetic diversity correlates to an increase in “ice-free days,” especially during the polar bear mating season of spring. Ice, in the Arctic, is essential for migration and mobility through areas that otherwise become dangerous or impossible to navigate. As sub-populations of polar bears become more fragmented and isolated due to this change in their habitat, they are in-breeding at a higher rate to survive.

When species inbreed, they lose valuable genetic diversity that allows them to adapt and thrive in their environment. Once this genetic information is lost, it takes generations to slowly rebuild, underscoring the importance of preservation before it’s too late.


Discussing the implications that the study has for conservation efforts, the team wrote that “increased levels of isolation between populations may increase inbreeding in the future, most likely with negative effects such as inbreeding depression,” which Nature defines as “the reduced survival and fertility of offspring of related individuals.”

While the future is always uncertain, it is clear that as long as businesses, governments, and individuals continue to turn a blind eye to climate change, there will be consequences for not only us, but the most vulnerable species on the planet. Read the full study here.

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