Climate warming threatens polar bears

A long-term study in the Hudson Bay of Canada confirmed that polar bears are losing weight and that little animals are born less and less when global warming has melted. melting ice - their habitat. Is this a prediction of what other polar bears will face soon?

In May, a mother polar bear left its terracotta cave, walking along Hudson Bay, Canada, looking for temperatures below zero to take care of baby bears. It has been fasting for 8 months and has halved its body weight, about 400 pounds. After a week or two of adjusting to the climate around the cave, it reaches the frozen water.

Fortunately, its appearance on the sea ice along the continental shelf occurs just in time for seals to enter the breeding season - its main food source.

From April and summer when the ice at the bay collapsed and the seal disappeared inside the freezing water area, it was on a desperate race against time to store enough fat to pass. Long summer and fasting period lasted. If it is too thin, there will be no milk and its children will die. Hunting is a difficult task. With large, heavy feet, used to snooze on ice and snorkel, it uses twice the energy to go compared to most other mammals. So it chased after its prey quite slowly, but thanks to its unique ability to smell, it could smell the prey from its cave up to a mile away. Normally, it would leave the stomach empty while waiting for the prey next to the cave entrance and wait for a seal to appear in front of it.

Polar bears, the largest terrestrial predator, appears on the ground in this harsh life about 200 to 300 years ago. Since then, taxonomists have named them Ursus maritimus , a sea bear. Known as a species that can swim up to 60 miles a day, they are really ' residents ' living on ice. The Arctic icebergs are home to those big creatures. However, in areas of Hudson Bay, ice is gradually leaving them, threatening the long-term survival war of bears that have existed for centuries in this area. Their desperate situation is the prediction of the challenge that other polar bear residents living in the far south will face in the coming decades.

Experts believe that the global warming phenomenon is making ice melt 2 weeks earlier every July than 20 years ago. In a study, NASA researcher Josenfino Comiso used satellite data to find the direction of movement of the smallest ice sheets and temperatures across the Arctic from 1978 to 2000. At the end of the year, he reported on the phenomenon of sea ice that seemed to be permanently melting faster than before, due to high temperatures and the interaction between ice, sea and air that accelerated melting process.

The early melting of ice is no worse for polar bears, especially for pregnant females and their children and their offspring . In Hudson Bay, the offspring are weaned in May and then they start to leave the cave. A month later, the adult bears will escape from the ice to molt, which is also the second source of food for polar bears. But when the ice disappears sooner, the source of their fat supply is depleted.

Ian Stirling, a scientist from the Canadian Wildlife Protection Agency, who has studied polar bears for more than 30 years, said: 'Nobody knows exactly how much of the fat of the bear's sword is in. Spring is stored and used throughout the year. Definitely more than 50% and can be about 70 to 75% higher. We all know this is a serious problem. '

Stirling and his colleagues also said that bears living along Hudson Bay are now lighter and live in tougher conditions than 20 years ago . They discovered this because their studies of polar white bears - tracking a group living separately for more than two decades have unusual changes in life expectancy. Researchers found that for every week of ice breaking earlier, the number of bears that came ashore was less than 22 pounds. And if the climate models introduced by British and American scientists have recently proved correct, the region's temperature will rise from 3 to 5 degrees in the past 50 years. With each increase, the broken ice will occur 1 week earlier.

1,200 bears live in the western Hudson Bay, which is one of the most remote places in the range of this species. As the Earth continues to warm up, there is not much hope for the unhappy living conditions in the far north - the home of about 25,000 bears in 20 different sub-territories. Of course, ice conditions in the Beaufort Sea off the coast of northern Alaska, home to other crowded white bear populations , are changing in a worrying way.

Longer summers in the Hudson Bay area are particularly challenging pregnant females and their children and their cubs. The mother bear weighs about 300 to 350 pounds after leaving the cave and needs to store 100 to 200 pounds before the ice melts. Healthy females during pregnancy often reach more than 400 pounds of fat. So a mother bear can spend half of her time hunting and seals every few days. It can eat more than 60 pounds of seal meat in a small meal (a typical male bear can lose 150 pounds in a short time).

In the largest areas, baby bears are weaned when they are two and a half years old. In a few years, fewer and fewer baby bears can survive and grow. The main cause of their death is the lack of food. When you become too skinny, your mother will easily stop taking care of her and run away from them. Andrew Derochor, a University of Alberta scientist who has studied these bears for 20 years, said: 'The lesser a bear is, the lower the survival rate and that is due to the thin bear cubs. than.'

Stirling said that if the ice melted in Hudson Bay as expected, there would be no bear living on the bay. Moreover, there is no place for them to go. People often ask whether polar bears can travel further north? But there is no answer. The environment in which polar bears come to live. In the meantime, there are a few bears that go beyond the far north, a faraway place, but perhaps not a friendly place for them. Stirling judged that if this situation persisted for a long time, it would be a bad thing for polar bears.

The link between warming climate and bear's declining living conditions can be demonstrated, Stirling intends to build a special data bank about the lives of bears. The bears in Hudson Bay are the animal group most noted by world researchers for being susceptible to their environment and Stirling's efforts to raise funds to protect the bear. Derocher argues that building a polar bear data bank for the survival of each individual. Stirling's research provides insight into the polar bear's life.

Other polar bear groups try to move away from the melting ice. But every year along the bay, almost all bears go ashore and gather in one place within a few months. For more than two decades, Stirling and his colleagues followed 80 percent of adult bears in the area. Each bear is monitored closely, weighed and tested for fat content.

The team was fortunate in the study when the western region of Hudson Bay had a hotter climate because of the greater impact of climate warming compared to the closer areas. That is why the change becomes clearer. Meanwhile the statistics show that the earth is heating up, but the temperature is different across regions. For example, the Hudson Bay area is colder every year than it was a few decades ago, although recently this area is also heating up.

In the early 80s, Stirling began to realize that bears seemed to be losing weight. Baby bears take longer to wean, so the children reproduce more slowly.

'It takes 20 years to have enough data to determine what's going on because there's always a bit of fluctuation every year. You can't see a change below unless you have a lot of time to look at it for a long time. '

Because arctic white bears play the most important role in the food chain, their circumstances are giving a timely warning of climate change to the entire Arctic region. Stirling said: 'Normally when you take big carnivores out of the ecosystem, you'll encounter serious changes. But what exactly happens, I think no one can say it before. Obviously it is a huge change to the Arctic ecosystem if there are no polar bears. '

Stiring is about to retire and thinks this is a time for young researchers to follow. According to Derocher and Nick Lunn, his colleague at the Canadian Wildlife Protection Department, he has two very enthusiastic students determined to continue his work. Lunn, who wants to spend more time studying the proliferation of individual animals throughout their lives, said: 'There is no other documentary about a more valuable Arctic animal than research. save this. If you let it go, just for a year, everything is gone. You cannot fill that void '. He noticed, at first, not every bear could be affected by global warming.

Meanwhile, Derocher plans further research on the impact of climate change on polar white bears. He said: 'I believe it is deeper knowledge of the interplay between ice sea, polar bears and their prey, and is also a key factor in understanding that the polar bear will against climate change in the coming years'. He also hoped to be able to further investigate the effects of toxic chemicals on polar white bears and other Arctic wildlife.

Derocher spends a lot of time thinking about which animal is like a polar bear, walking on ice, using predatory sense of smell during the dark night in the Arctic when the temperature is minus 40 degrees Fahr (about more than 4 degrees C).'You can't help but pay attention to an animal that can create a better life.'