Old And Busted: Polar Bears Are Doomed. New And Hot: Polar Bears Are Adapting

But, they’re still probably doomed

Polar bears are adapting to climate change at a genetic level – and it could help them avoid extinction

The Arctic Ocean current is at its warmest in the last 125,000 years, and temperatures continue to rise. Due to these warming temperatures more than two-thirds of polar bears are expected to be extinct by 2050 with total extinction predicted by the end of this century.

First, the majority of that time period was an ice age. Second, they have absolutely no direct measurement data from during previous Holocene warm periods to say this.

But in our new study my colleagues and I found that the changing climate was driving changes in the polar bear genome, potentially allowing them to more readily adapt to warmer habitats. Provided these polar bears can source enough food and breeding partners, this suggests they may potentially survive these new challenging climates.

We discovered a strong link between rising temperatures in south-east Greenland and changes in polar bear DNA. DNA is the instruction book inside every cell, guiding how an organism grows and develops. In processes called transcription and translation, DNA is copied to generate RNA (molecules that reflect gene activity) and can lead to the production of proteins, and copies of transposons (TEs), also known as “jumping genes”, which are mobile pieces of the genome that can move around and influence how other genes work. (big snip)

Over time the DNA sequence can slowly change and evolve, but environmental stress, such as warmer climate, can accelerate this process. (snip)

Our research found that some genes linked to heat-stress, ageing and metabolism are behaving differently in the south-east population of polar bears. This suggests they might be adjusting to their warmer conditions. Additionally, we found active jumping genes in parts of the genome that are involved in areas tied to fat processing – important when food is scarce. This could mean that polar bears in the south-east are slowly adapting to eating the rougher plant-based diets that can be found in the warmer regions. Northern populations of bears eat mainly fatty seals.

So, can we compare these minor changes from during the previous Holocene warm and cool periods over the last 8,000 years? Darwin and others noted that many animals and birds saw minor changes during different climate periods, like drought and wet. People living in cold regions adapt to that while ones in hotter areas adapt physically. That’s how life works.