Is the end of the polar bears near?

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Scientists have predicted for the first time when, where and how polar bears are likely to disappear, warning that if greenhouse gas emissions remain on their current trajectory, all but a few polar bear populations in the Arctic will likely They will disappear by the year 2100. As early as 2040, many polar bears will likely begin to experience reproductive failure, leading to local extinctions, according to a study published in Nature Climate Change . According to The Guardian , the study examines how bears will be affected under two different greenhouse gas emissions scenarios. Researchers found that under a business-as-usual emissions scenario, polar bears will likely only remain in the Queen Elizabeth Islands, the northernmost group of Canada's Arctic archipelago, by the end of the century. And even if greenhouse gases are moderately mitigated, most polar bear populations in the Arctic are likely to experience reproductive failure by 2080. Scientists estimate there are fewer than 26,000 polar bears left, spread across 19 different subpopulations ranging from the ice landscapes of Svalbard, Norway, to Hudson Bay in Canada and the Chukchi Sea between Alaska and Siberia. Polar bears cannot find enough sustenance on land and rely on sea ice for hunting. They often stake out the seals' breathing holes in the ice, waiting for hours for a meal of fat to rise to the surface. But as sea ice decreases due to climate change, so will polar bears.

Is the end of the polar bears near? Péter Molnár, a biologist at the University of Toronto Scarborough, and lead author of the study, said: It has been clear for some time that polar bears will suffer under climate change, but what was not entirely clear was when we would expect large declines in polar bear survival and reproduction that could lead to their extirpation. We didn't know if that would happen early or Bulgaria Mobile Number List later in this century. Péter Molnár, a biologist at the University of Toronto Scarborough, and lead author of the study. Polar bears draw on energy reserves built up during the winter hunting season to spend the summer months on land or time spent on ice in unproductive waters. Although they are accustomed to fasting for months, their body condition, reproductive capacity, and survival will eventually decline if they are forced to go too long without food. In the Beaufort Sea population of southern Alaska, biologists have already seen polar bear numbers drop by 25 to 50% during periods of low ice, when the bears have been forced to fast for too long. And in western Hudson Bay, one of the southernmost polar bear habitats, the population has declined about 30% since .



To determine when bears might reach their critical physiological limit, Molnár and his colleagues estimated how thin and fat polar bears might be to model the animals' energy use to get the threshold number of days they can fast before they decline. pup and adult survival rates. They then combined those thresholds with the projected number of future sea ice-free days to determine how populations in different parts of the Arctic will be affected. Molnár also commented: Even if we mitigate emissions, we will still see some subpopulations become extinct before the end of the century. This includes polar bears in the most vulnerable southern ice zones of Western Hudson Bay, Davis Strait, and Southern Hudson Bay, but we would have substantially more populations persisting by the end of the century, even with reduced reproduction. , compared to a business emissions scenario. Péter Molnár, a biologist at the University of Toronto Scarborough, and lead author of the study. The study examined 13 of the world's 19 polar bear subpopulations, representing 80% of the species' total population. Bears that inhabit an area known as the Archipelago ecoregion in the Canadian Arctic were not included since the geography of the area (islands and narrow channels) made it too difficult to predict the future extent of the ice.