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Thin ice, eternal chemicals - the polar bear faces a double problem

For years, the polar bear on the thinning ice floe was the motive for anyone anywhere in the world warning of the consequences of climate change.

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Thin ice, eternal chemicals - the polar bear faces a double problem

For years, the polar bear on the thinning ice floe was the motive for anyone anywhere in the world warning of the consequences of climate change. In the meantime, humanity has fundamentally understood that a changing climate with rising temperatures and more frequent and severe extreme weather events does not only affect the predators in the Arctic. Other images have long served as symbols for the climate crisis, such as those of the destructive floods in the Ahr Valley in 2021 or the equally deadly forest fires in Australia.

The climate crisis has long since been felt where people live. Or as UN Secretary-General António Guterres recently said metaphorically: “Humanity is on thin ice – and this ice is melting fast.”

At the same time, the situation of the white giants has not necessarily improved. Global warming is pushing them to new regions and eating habits, and researchers are seeing alarming signs that chemicals found deep in the ice could be reaching the animals, too. So it's time to ask: how is he, the polar bear?

There is no blanket answer to this question. "It depends a lot on where you look," says polar bear researcher Jon Aars of the Norwegian Polar Institute. “On Spitsbergen, for example, everything is still fine with them. We see many different effects on what they are doing and where they are, but not that their population is declining or that they are unable to reproduce.”

Elsewhere in the Arctic, they are faring much worse due to the warmer climate and receding sea ice. They would struggle the most in more southern areas of the Arctic, such as Canada's Hudson Bay, but also north of Alaska in the Beaufort Sea, where several years of poor ice conditions have plagued them.

However, hardly any other place in the world is as closely associated with polar bears as Svalbard. Today, according to Aars, an estimated 250 specimens live around and on the northern Norwegian archipelago, and around 3,000 throughout the Barents Sea region, which extends to Russia. He is one of the driving forces behind Spitsbergen tourism, an encounter from a safe distance of one or two kilometers is an unforgettable experience. At the same time, no secret is made of the danger posed by the predator.

In total, the polar bear population is estimated at around 26,000 individuals. With increasing climate change, the region is heating up much faster than other parts of the world, which is particularly noticeable on Svalbard. "It's one of the regions of the world where you can really see the climate warming," says arctic researcher Bjørn Munro Jenssen of the University Center of Spitsbergen (UNIS).

This also affects the situation of polar bears, as researcher Aars explains: "We see that many of the bears are much further north today - simply because they spend a lot of time on the sea ice and the ice for much of the year 200 , 300 kilometers further north than usual.” The time to hunt seals is also getting shorter and shorter for them. On Spitsbergen they also hunted reindeer and plundered bird nests much more frequently.

Another problem may be added to the problem of melting sea ice: An international research team led by environmental chemist William Hartz (also UNIS) has found 26 different PFAS compounds in an ice core in a remote part of Spitsbergen called Lomonosovfonna. These are chemical substances that are used, for example, to make pans or jackets dirt and water-repellent.

Their problem: They don't simply disappear from the environment, which is why they are often referred to as "forever chemicals". They can also be harmful to health and the environment, which is why the German government is currently working with other European countries to ban the majority of these substances.

They also pose a risk to bears: the concern is that the chemicals carried through the atmosphere from distant regions in America, Europe and Asia will find their way into Arctic glaciers and from there into the sea, Jenssen explains. They could then eventually make it up the entire food chain - from plankton to fish and seals to said polar bear.

This could mean that the animals face a double problem, as Hartz says. "Polar bears are exposed to toxic man-made chemicals while also having to cope with changing habitats, less sea ice and changing hunting grounds," he says. The PFAS levels in polar bears on Svalbard are similar to those in the blood of people living near chemical plants in China, Hartz said. "That's pretty alarming."

Polar bear researcher Aars is also watching the PFAS developments with concern. "We know they have an effect on animals, but we don't yet know much about how bad it is. It's not good - but we don't know how bad it is," he says.

"Aha! Ten minutes of everyday knowledge" is WELT's knowledge podcast. Every Tuesday and Thursday we answer everyday questions from the field of science. Subscribe to the podcast on Spotify, Apple Podcasts, Deezer, Amazon Music, among others, or directly via RSS feed.

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