Effects Of Global Warming In The Arctic – Polar bears could disappear by the end of the century due to shrinking Arctic ice if global warming continues unabated, scientists said Monday.

Almost all 19 subpopulations of polar bears, from Alaska’s Beaufort Sea to the Siberian Arctic, will be wiped out because the loss of sea ice would force the animals to stay on land and away from their food reserves for long periods, researchers say. say. he said. Prolonged fasting and reduced nursing of pups by mothers would lead to a rapid decline in reproduction and survival.

Effects Of Global Warming In The Arctic

Effects Of Global Warming In The Arctic

“There is very little chance that polar bears will survive anywhere in the world, except perhaps in the high Arctic, in a small subpopulation,” if greenhouse gas emissions continue at so-called normal levels, Peter K. Molnar said. , a researcher at the University of Toronto Scarborough and lead author of the study, published Monday in the journal Nature Climate Change.

With Thick Ice Gone, Arctic Sea Ice Changes More Slowly

Even if emissions are reduced to more moderate levels, “unfortunately we will lose some, especially some of the more southerly populations, due to the loss of sea ice,” said Dr. Molnar.

The plight of polar bears has long been a sore point in the human-caused climate change debate, used by scientists and environmentalists as well as deniers in their arguments.

According to rough estimates, there are about 25,000 polar bears in the Arctic. Their primary habitat is sea ice, where they hunt seals while they wait to swim out into holes in the ice. In some areas, bears remain on the ice year-round, but in others, spring and summer melt drives them ashore.

“You need sea ice to catch food,” said Dr. Molnar. “There is not enough food on earth to support the polar bear population.” But bears can fast for months, subsisting on energy from the fat they’ve accumulated from eating seals.

Effects Of Global Warming Around The World (photos)

Arctic ice grows in winter, melts and retreats in spring and summer. As the region has warmed rapidly in recent decades, summer sea ice extent has decreased by about 13% per decade compared to the average from 1981 to 2010. Some areas of the Arctic that previously had year-round ice now experience ice-free periods during the summer. Other regions are now ice-free for a longer period of the year than in the past.

Dr. Molnar and his colleagues examined 13 subpopulations that represent about 80 percent of the total bear population. They calculated the bears’ energy needs to determine how long they could survive (or, in the case of females, survive and nurse their cubs) while fasting.

Combining this with climate model projections of ice-free days by 2100, if current rates of warming continue, they found that for almost all subgroups, the length of time animals would be forced to fast would eventually exceed the current duration. able to fast.

Effects Of Global Warming In The Arctic

The problem is compounded by the fact that a longer period of fasting means a shorter period of eating. “Not only do bears have to fast longer and need more energy to survive, but it’s also harder for them to store that energy,” he said.

Global Warming Is Driving Polar Bears Toward Extinction, Researchers Say

During fasting, bears move as little as possible to conserve energy. But melting sea ice and shrinking populations create new problems—for example, the need to devote more energy to finding mates—which could further affect survival.

Even under more modest warming projections, where greenhouse gas emissions peak by 2040 and then begin to decline, many subgroups would still be wiped out, the study shows.

Over the years, polar bears have become a symbol for both those who argue that urgent action is needed to combat global warming and those who argue that climate change is not happening or, at best, that the problem is exaggerated.

Groups including the Cato Institute, a libertarian research organization that disputes aspects of climate change, have said concerns about the bears are unwarranted, arguing that some research shows the animals have survived periods of heat. But scientists say that during earlier warm periods, the bears probably had important alternative food sources, especially whales, that they don’t have today.

How Does Climate Change Affect Arctic Animals?

Poignant images of bears in ice-insulated crevasses or on land foraging have been used by conservation groups and others to demonstrate the need for action to reduce warming. However, sometimes these images are not what they seem.

After National Geographic published a video online in 2017 of an emaciated bear scavenging for trash in the Canadian Arctic, the magazine acknowledged that the bear’s plight may not be related to climate change. The scientists stressed that there was no way to know what was wrong with the bear; he could have been sick or very old.

The new research does not include projections in which emissions would be significantly reduced, said Cecilia M. Bitz, an atmospheric scientist at the University of Washington and an author of the study. Researchers had to be able to determine, as precisely as possible, the periods during which sea ice would disappear from a given region. “If we wanted to look at many models, we wouldn’t be able to do that,” said Dr. Bitz.

Effects Of Global Warming In The Arctic

Andrew Derocher, a polar bear researcher at the University of Alberta who was not involved in the study, said the results are “very consistent with what we observe,” such as tracking animals in the wild. “The study clearly shows that polar bears will do better with less warming,” he added. “But whichever scenario is considered, there are serious conservation concerns for this species.”

How Sea Ice In The Arctic And The Antarctic Is Influenced By Climate Change

Of the 19 subpopulations, little is known about some of them, especially those in the Russian Arctic. Among the subpopulations studied, some – mainly those located in areas with less ice loss – have so far shown little population decline. But others, including the southern Beaufort Sea, northeastern Alaska and western Hudson Bay in Canada, are severely affected by melting sea ice.

One analysis found that the southern Beaufort Sea subpopulation declined by 40 percent to about 900 bears in the first decade of this century.

According to dr. To Derocher, one of the drawbacks of these studies is that while they can show long-term trends, “it becomes very difficult to model what happens from year to year.”

Polar bear populations can be very sensitive to drastic changes in conditions from year to year, he said. “One of the big challenges in conservation is that one or two bad years can rob a healthy population and push it to very low levels.”

Emaciated Polar Bear, What’s To Blame?

Henry Fountain specializes in the science of climate change and its impacts. He wrote about science for The Times for more than 20 years and traveled to the Arctic and Antarctic. Learn more about Fontaine Henry

The print version of this article appears in Section A, page 12 of the New York edition under the headline: Climate change condemns polar bears to a bleak, limited future. Order a reprint | Today’s work | On an early November morning, Dr. Leslie Field found himself driving a snowmobile about 300 miles above the Arctic Circle, shooting straight toward the sunrise in subzero temperatures. She has a cold and is expected to struggle on this journey from her home in California to one of the coldest, most remote parts of the country in the winter – when there are only 2.5 hours of sunlight a day.

“All of a sudden there’s a rainbow I’m jumping into,” she said. This time of year, the sun seems to rise and set almost infinitely slowly in Utqiaġvik (formerly Barrow), Alaska, painting the sky in eternal twilight colors of electric blues and pinks. As the sun stretched across the horizon, it presented a stunning celestial light show. Instead of darkness and gloom, she saw incredible beauty. And with all this beauty, “I realized I was doing the most important thing I could do for the planet.”

Effects Of Global Warming In The Arctic

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Global Warming Is Melting Antarctic Ice From Below

Utqiaġvik is a place that many scientists call “ground zero of climate change”. There, sea ice practically disappears in summer, as is the case in much of the Arctic, where warming is accelerating more than twice as fast as in the rest of the Northern Hemisphere. Coastal villages will be underwater within decades as warmer oceans alter the migration and spawning grounds of whales, fish and other creatures that the indigenous Iñupiat have hunted and revered for thousands of years.

For the past three years in Utqiaġvik, Field and a research team from Ice 911, a Silicon Valley nonprofit, have been testing an unusual solution for restoring Arctic ice. Its innovative approach is poised to end one of the most significant impacts and impacts on climate change, becoming part of a global climate restoration solution that could

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