Unless the pace of global warming slows অথবা stops, polar bears could disappear within a century, says a বিশ্ববিদ্যালয় of Alberta expert in Arctic ecosystems.
While it has been known for some time that the polar ভালুক is in trouble, new research shows that Arctic ice - the polar bear's primary habitat - is melting much faster than scientists had believed, says U of A biologist Dr. Andrew Derocher.
"The climate predictions coming out are প্রদর্শিত হচ্ছে massive changes in sea-ice distribution," ব্যক্ত Derocher, who follows polar bears to see how they adapt to changing conditions. If the predictions are correct, he says, "we'll certainly lose polar bears in a lot of areas where we currently have them." Ice conditions in the Beaufort Sea, for example, are already changing dramatically.
The world's largest terrestrial carnivores, polar bears rely on sea ice to survive, using it to pass between forest dens and hunting grounds where they prey on seals. There are about 15,000 polar bears in northern Canada, accounting for about two-thirds of the world's total population.
Derocher shared his মতামত Jan. 6 at a symposium on Arctic biology in Toronto. It was the biggest gathering of Canadian Arctic biologists in আরো than a decade, says co-chair Dr. David Hik, also of the U of A. Many of the talks addressed the impact of climate change on northern ecosystems.
Derocher says if global warming continues unchecked, some remnant populations of polar bears may manage to hang on in the high Canadian archipelago অথবা on permanent polar ice at very high latitudes. But the potential for extinction is still a cause for concern: "You don't have to be a polar scientist to see that if আপনি take away all the sea ice, আপনি don't have polar bears any more."
To make matters worse, sea-ice melting is accelerated দ্বারা "positive feedback loops." Sea ice acts as a reflector of solar energy, but when the ice disappears, the ocean absorbs that heat energy, which in turn prevents ice from freezing.
"Once climate warming initiates, আপনি get into a self-warming cycle," ব্যক্ত Derocher, who earned international renown as a polar ভালুক and northern studies expert at the Norwegian Polar Institute in Tromso before returning to the বিশ্ববিদ্যালয় of Alberta, where he completed his doctorate. "That's why the urgency on the issue for polar bears now."
He adds that it is possible a warmer climate will improve polar ভালুক and সীল habitats in the short term, mainly in higher latitudes where ice is too thick for সীল hunting. But these areas are small, he says, and will only support a fraction of the ভালুক population.
Polar bears can tolerate some environmental variation from বছর to year, foregoing reproduction in any প্রদত্ত বছর if conditions are poor." With too much variation, however, reproduction will fall off dramatically, and populations will quickly decline. Scientists have no evidence yet of a drop in polar ভালুক populations, but body weights and reproductive rates of bears in the Hudson উপসাগর are on the decline," ব্যক্ত Derocher.
Hik says there is also new research looking at the harmful effect of drought-related forest fires on polar ভালুক dens, which are built in mature forests.
"When আপনি burn the forest down, it blackens the earth, and these dens burrowed into the permafrost collapse," ব্যক্ত Hik. "Many of them are created over centuries দ্বারা successive generations of bears scraping deeper and deeper in." The area around Churchill, Manitoba is one such area that has been losing these dens.
While it has been known for some time that the polar ভালুক is in trouble, new research shows that Arctic ice - the polar bear's primary habitat - is melting much faster than scientists had believed, says U of A biologist Dr. Andrew Derocher.
"The climate predictions coming out are প্রদর্শিত হচ্ছে massive changes in sea-ice distribution," ব্যক্ত Derocher, who follows polar bears to see how they adapt to changing conditions. If the predictions are correct, he says, "we'll certainly lose polar bears in a lot of areas where we currently have them." Ice conditions in the Beaufort Sea, for example, are already changing dramatically.
The world's largest terrestrial carnivores, polar bears rely on sea ice to survive, using it to pass between forest dens and hunting grounds where they prey on seals. There are about 15,000 polar bears in northern Canada, accounting for about two-thirds of the world's total population.
Derocher shared his মতামত Jan. 6 at a symposium on Arctic biology in Toronto. It was the biggest gathering of Canadian Arctic biologists in আরো than a decade, says co-chair Dr. David Hik, also of the U of A. Many of the talks addressed the impact of climate change on northern ecosystems.
Derocher says if global warming continues unchecked, some remnant populations of polar bears may manage to hang on in the high Canadian archipelago অথবা on permanent polar ice at very high latitudes. But the potential for extinction is still a cause for concern: "You don't have to be a polar scientist to see that if আপনি take away all the sea ice, আপনি don't have polar bears any more."
To make matters worse, sea-ice melting is accelerated দ্বারা "positive feedback loops." Sea ice acts as a reflector of solar energy, but when the ice disappears, the ocean absorbs that heat energy, which in turn prevents ice from freezing.
"Once climate warming initiates, আপনি get into a self-warming cycle," ব্যক্ত Derocher, who earned international renown as a polar ভালুক and northern studies expert at the Norwegian Polar Institute in Tromso before returning to the বিশ্ববিদ্যালয় of Alberta, where he completed his doctorate. "That's why the urgency on the issue for polar bears now."
He adds that it is possible a warmer climate will improve polar ভালুক and সীল habitats in the short term, mainly in higher latitudes where ice is too thick for সীল hunting. But these areas are small, he says, and will only support a fraction of the ভালুক population.
Polar bears can tolerate some environmental variation from বছর to year, foregoing reproduction in any প্রদত্ত বছর if conditions are poor." With too much variation, however, reproduction will fall off dramatically, and populations will quickly decline. Scientists have no evidence yet of a drop in polar ভালুক populations, but body weights and reproductive rates of bears in the Hudson উপসাগর are on the decline," ব্যক্ত Derocher.
Hik says there is also new research looking at the harmful effect of drought-related forest fires on polar ভালুক dens, which are built in mature forests.
"When আপনি burn the forest down, it blackens the earth, and these dens burrowed into the permafrost collapse," ব্যক্ত Hik. "Many of them are created over centuries দ্বারা successive generations of bears scraping deeper and deeper in." The area around Churchill, Manitoba is one such area that has been losing these dens.