The climate crisis is not only taking a devastating toll on humanity with a carousel of increasingly extreme events, but on the planet’s biodiversity as a whole.
Rising ocean temperatures are melting the sea ice and decreasing their hunting grounds. The wild population of polar bears is estimated to be between 21,000-23,000. However, it is difficult for us to determine if there is a decline in adult populations due the lack of long-term data.
Recent aerial counts of polar bear cubs aged one- and two-years-old show a dramatic decline in the number of bears reaching adulthood than in the 1990s. Those cubs, called “yearlings”, used to account for 12 per cent of the polar bear population. They now make up only 3 percent.
Recent news stories have focused on depressing images of emaciated polar bears stranded on ice flows and the increased – though still rare – numbers of aggressive encounters between the generally reclusive polar bears and humans. Three people were attacked by a polar bear in August after it ate a carcass close to their cabin in Sanirajak (Nunavut), Canada. According to the CBCAll three survived the attack, but suffered serious injuries.
In August, helicopters were called to help scare seven polar bears from stalking a Siberian reindeer captive. According to reports, the bears were aggressive towards the reindeer and their human guards because they were hungry. In 2014, Arviat village children from the Canadian Arctic gathered inside a community building dressed in Halloween costumes as a trio polar bears sniffed around outside looking for food.
However top polar bear researchers caution against focusing on these incidents, noting that it is the conditions – not the bears – that have changed.
“It’s important to distinguish between a behavior change, as we would often think of it, but think of it in the context of something the bears have to do because their habitat is gone,” Dr Steven Amstrup (PBI chief scientist) said. The Independent.
Since 2010, Dr. Amstrup has been researching the polar bears for the non profit. Before joining PBI he spent 30 years at the US Geological Survey working in Alaska’s Beaufort Sea researching the bears, and has served as a chair on the International Union for the Conservation of Nature’s Polar Bear Specialist Group.
He stated that the main threat to the global population of polar bears is climate-driven sea ice melting. According to NOAA’s 2021 Arctic report card, the region experienced its warmest autumn since records began in 1900. Post-winter sea levels were at their lowest level since NOAA began monitoring them a decade back. These changes have devastating consequences for the polar bear hunting ground.
Polar bears predominantly eat two species of Arctic seals – bearded and ring. The seals build dens from snow that falls on sea ice in order to give birth. Seal pups, along with the adults, account for most of the polar bears’ daily caloric intake when they venture onto ice.
Less sea ice, and there’s fewer places for seals to build birthing dens, and in turn, fewer opportunities for polar bears to feed. The snow melts in the ocean water and does not accumulate, which means that ice is freezing later in the year.
Polar bears now have fewer seals to eat, so they have had to expand their hunting areas and find new food sources. The following reports were submitted by the Royal Society Open Science journalIt was found that polar bears visit nesting areas of birds like eider more often and eat their eggs and eggs.
These Arctic ground bear species are at risk from the changes in hunting methods. They also need to be replaced with enough calories by a more nutritious diet.
Seals are like “fat pills” for the bears, according to Dr Amstrup. Dr. Amstrup says that feeding on birds and eggs can’t replace the energy required by polar bears to survive, reproduce, and thrive.
While some Russia reportsSome have suggested that polar bears may be turning to cannibalism. Dr Amstrup stated that such incidents are rare and that all bears kill each other. It usually occurs between adult males as well as cubs in order to free up nurse females for breeding.
Worse, bears are reported to be visiting human settlements more often. Although the Arctic is often viewed as a barren desert of snow and ice by some, it is actually home more than 21,000 species of animals, plants and microbes, along with four million people.
Dr Amstrup said polar bears have been scavenging leftover bowhead whale remains left by the Iñupiat people, who are native to Alaska, creating both risks for the Indigenous community and the bears. In other areas, polar Bears are attacking captive reindeer herds.
Rod Downie is the chief advisor for polar regions for World Wildlife Fund UK. He said that polar bears were a significant threat to polar communities all over the globe.
“I’m a father, when I walk my kids to school I look out for threats. For me, it’s things like traffic, but for people living in northern communities, they could be facing down a 500-600kg bear that would be more than capable of tearing a child to shreds,” he said.
Both WWF as well as PBI have been working to mitigate the threat to bears and people. PBI is experimenting with ground-based radar – a technology generally used by the military – to detect a bear’s approach, allowing people to scare off the creature before it reaches a human settlement. WWF has set up community-based bear patrols to respond to bear threats without using lethal force.
A lack of adequate food sources has also led to fewer bear cubs reaching the age of adulthood. While bears are still mating at the same rates, fewer of the cubs are making it the stage known as a “yearling”.
“Many people don’t quite appreciate when biologists say that the survival of cubs is not as good as it used to be, what they’re really saying is – it’s a euphemism that means more polar bear cubs are starving to death,” Dr Amstrup said.
There are scattered reports of polar bear interbreeding, which can lead to the emergence of recessive genes and the narrowing in genetic diversity among populations.
However, there have been some reports of polar bears mating and producing hybrid offspring with grizzly bears. These cases are rare.
Although a hybrid bear might help ensure that some elements of the Arctic bear survive the decline, researchers like Dr Amstrup don’t accept this scenario.
“If we allow the world to continue to warm to a point where polar bears have totally disappeared, there may be a few polar bear genes in something that looks like a grizzly bear. That’s not really a very satisfying outcome,” he said.
“More importantly though, polar bears are more likely to starve out before there’s any chance that they could be bred out of existence.”
Some studies project that the polar may become extinct by 2100, and the International Union for Conservation of Nature has included the bears on its “red list” of threatened species, WarningA possible 30% population decline in the next 35 years
Dr Amstrup & Mr Downie are optimistic, however, and believe that saving the polar bears is entirely within our control.
“From the standpoint of the greenhouse gas emissions pathway society is on, polar bears don’t look like they’re going to make it. But we have control over that,” Dr Amstrup said.
“So if we halt warming in time, we can save the polar bears. And oh, by the way, if we do that, it will benefit the rest of life on Earth as we know it, including ourselves.”