As global temperatures continue to rise at alarming rates, climate change threatens to wipe out entire groups of animal species. In an article published by Evolution Letters, researchers state that “[h]uman-induced climate change is increasingly molding the selective environment in which species must either adapt, move, or face extinction.”
Now, scientists estimate that more than two-thirds of polar bears will go extinct by 2050, with total extinction predicted by the end of this century.
Polar bears show genetic changes linked to survival
In a recent study, researchers from the University of East Anglia found that polar bears have undergone changes in their DNA that would allow them to adapt more readily to warmer habitats. The full scale of adaptation, however, depends on whether polar bears have sufficient food sources and breeding partners. If these conditions are met, they may potentially survive the worsening climate conditions.
The researchers found that some genes linked to heat stress, ageing, and metabolism behaved differently for the polar bears found in south-east Greenland. These were found alongside DNA changes in areas tied to fat processing. This finding suggests that the bears in the south-east region are slowly adapting to rougher plant-based diets, as compared to the northern populations of bears that typically feed on fatty seals.
The changes in their genes were found to be strongly related to rising temperatures in south-east Greenland, which indicates that stressful environmental conditions, including rapidly warming climates, can accelerate the process of DNA evolution.
Hybrid species emerge as habitats and ranges shift
Gene evolution and species hybridisation have been observed to be increasingly common phenomena in response to climate change.
In 2023, a hybrid bird species (a cross between a green jay bird and a blue jay bird) was discovered for the first time. Due to environmental changes caused by climate change, the likelihood for interactions between species that have never interacted before increases, possibly leading to new ecological communities.
The “pizzly” bear, a cross between a polar bear and a grizzly bear, is another example. As temperatures rise and polar bears spend more time on land and less time on ice, with brown and black bears also gradually infiltrating the Arctic, sightings of these hybrids are expected to climb according to experts.
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Adaptation has limits
Hybridisation may be beneficial for some species, and it may help them adapt to environmental changes. Such processes are not new or foreign. However, experts have expressed concerns that the rate at which this is occurring may be accelerating too quickly for it to be entirely beneficial.
For example, when cold-blooded species like lizards, frogs, and fish undergo rapid adaptation to warmer temperatures, it often results in population declines as individuals unable to tolerate higher temperatures die. Even if they do adapt to survive climate change, their smaller populations may go extinct due to inbreeding, harmful new mutations, or misfortunes such as disease epidemics.
Conversely, another concern is that the rate of evolution is disproportionately slow compared to the rate of climate change. For animals that take several years to reach breeding age, the climate would have worsened by the time their offspring are born. Subsequently, genes that were previously advantageous for the parents’ survival become redundant for their offspring. Each generation may fail to thrive due to their inability to accommodate to the changing environmental conditions, drawing even closer to extinction.
At the same time, many animal species face the threat of the loss of their natural habitats due to human activity. Together, these pressures may alter ecosystems and biodiversity at a pace that Mother Nature cannot keep up with. This underscores the importance of mankind’s efforts to slow climate change before other species go extinct at the cost of our actions.
Editor’s Note: The opinions expressed here by the authors are their own, not those of Impakter.com — In the Featured Photo: Close-up shot of a polar bear. Featured Photo Credit: Valentin
