Researchers have found that in the last 20 thousand years the number of polar bears on the island has decreased by tens of percent, as a result of a warming of 0.5 degrees. So what will happen when the sea around Greenland warms by 5 degrees?

The fact that the polar bears in Greenland are under threat has made them a symbol of dealing with the challenges of the climate crisis which is manifested in this region in the accelerated melting of the glaciers over the years. In fact, this is not only a contemporary phenomenon, but has deep historical roots, as the number of polar bears in Greenland has been decreasing over a period of 20 thousand years.

Dr. Michael Westbury and Prof. Eline Lorenzen from the Globe Institute at the University of Copenhagen led a new study, the findings of which were published in the journal Science Advances. In the study, the DNA and food of living polar bears were analyzed, as well as historical climate data and the habitat of polar bears around Greenland.

By analyzing the genetic material of the polar bears, a window was opened to the past, through which historical insights were obtained regarding their development. The analysis we conducted revealed that the number of polar bears has been significantly reduced several times since the last ice age,” said Prof. Lorenzen. “Over the years, the rise in sea water temperature has accelerated the decline in the polar bear population. When the sea temperature rises, there is less sea ice, and as a result, fewer seals, which the polar bears feed on,” added Dr. Westbury, who along with his research colleagues were surprised to discover that even a small environmental change had a large effect on the polar bears.

A disturbing connection between population decline and environmental changes has been discovered. A relatively small increase in water temperature and a small reduction in the amount of sea ice caused a pretty dramatic decline in the polar bear population,” said Dr. Westbury.
Due to the increase in the emission of polluting greenhouse gases, such as carbon dioxide, global warming has accelerated over the years, a phenomenon that is clearly visible in Greenland and the Arctic region. “The current development is unprecedented compared to what the polar bear has experienced over the past 20,000 years, when the future does not seem to bode well for this species,” said Dr. Westbury.

The findings of the new study indicate that the temperature of the water around Greenland has increased by 0.5-0.2 degrees Celsius over the past 20,000 years – a trend that has caused a 20-40% decrease in the polar bear population. “Looking ahead, we are facing a 2-5°C increase in sea temperature around Greenland.

This is a 10-fold increase in temperature changes compared to the last 20,000 years. The polar bear stands at the top of the food chain in the Arctic region, and symbolizes the pressure that the marine ecosystems in this region are under,” explained Prof. Lorenzen, who emphasized that this is a symptom of something bigger, as ecosystems will be adversely affected by climate change not only in this region, but throughout the planet.

The research also shows that polar bears are able to change their diet, which may help them adapt to climate change. “Polar bears adapt their diet according to the environmental changes they experience. In East Greenland, for example, males and females do not compete with each other, because males consume different species of seals, while females eat ringed seals (fossa ringed). On the other hand, in West Greenland, the situation is different , because males and females live on the same diet, but with greater availability due to ocean currents in the west of the island,” said Dr. Westbury.