Majestic, getting hungry and in danger of disappearing, Polar bear It depends on what is melting on our warming planet: sea ice.
In the harsh and unforgiving ArcticIn places where cold is not only a way of life but also a necessity, polar bears stand out. But where it lives, where it hunts, where it eats—it is disappearing under its feet during the critical summer.
“They have always been a revered species, dating back hundreds and hundreds of years,” said Steve Amstrup, a long-time government polar bear researcher and current chief scientist of Polar Bear International. “Polar bears have something special.”
Scientists and advocates point out that the polar bears marked as “threatened” on the list of endangered species are a white-hot warning sign for other parts of the planet-“canaries in the cryosphere.” When world leaders met in Glasgow, Scotland, trying to step up efforts to curb climate change, the ghost of polar bears enveloped them.
Inger Andersen, head of the United Nations Environment Programme, once led the International Union for Conservation of Nature, responsible for monitoring and classifying species in distress. She asked: “Do we really want to be the generation that sees the end of the survival of such a majestic animal as the polar bear?”
Arctic sea ice-frozen sea water-shrinks when it warms in the summer, and then forms again in the long winter. Scientists say the extent to which it shrinks is where global warming begins. The more sea ice shrinks in summer, the thinner the overall ice is because the ice in the first year is weaker.
University of Manitoba researcher Julienne Stroeve said summer without sea ice is inevitable. Many other experts agree with her.
Former NASA chief scientist Waleed Abdalati (Waleed Abdalati) is one of them.
Polar bears have become a representative of climate change-this is the status of the species
“This is something human civilization has never known,” Abdalati said. “It’s like taking a sledgehammer against the climate system and doing something big.”
The situation that has warmed in the ocean and the air has already happened-like a freight train in motion. So, in any case, the earth will soon see a summer of less than 1 million square kilometers of sea ice scattered in a small area of the North Pole.
Mark Serez, director of the National Snow and Ice Data Center, said the biggest question is when the Arctic will “look like a blue ocean.”
Experts say that it may be as early as the 2030s, most likely in the 2040s, and almost certainly in the 2050s.
The Arctic is warming twice as fast as the rest of the world. John Walsh, a scientist at the University of Alaska at Fairbanks, said that in certain seasons, it is warming three times faster than in other parts of the world.
That’s because of the so-called “Arctic Amplification”. Essentially, the white ice of the Arctic reflects heat. Scientists say that when it melts, the dark ocean absorbs more heat, thereby warming the ocean faster.
Polar bear connection
There are 19 different polar bear subgroups in the Arctic. Each is a little different. Some did run into trouble, especially the southernmost ones, while others were very close to stability. But their survival from one place to another is closely related to sea ice.
“When you go to the North Pole and see what happens with your own eyes… it’s frustrating,” said Christine Ryder, a marine biologist at the University of Washington, who has studied polar bears in Baffin Bay.
Shrinking sea ice means shrinking polar bears, literally.
In summer, polar bears hunt and eat on the ice, eat and drink and gain weight to support them through the winter. Amstrup said they prefer areas covered by ice more than half because this is the most productive hunting and feeding ground. The more ice, the more they move around and the more they eat.
Just 30 or 40 years ago, bears enjoyed a buffet of seals and walruses on the ice.
In the 1980s, “males were huge, females reproduced regularly, and cubs survived well,” Amstrup said. “The population looks good.”
Amstrup said the bears did not perform well due to the loss of ice. One sign: a higher percentage of cubs die before their first birthday.
Polar bears are land mammals that have adapted to the ocean. The animals they eat-mainly seals and walruses-are aquatic.
Bears perform best when they can hunt in shallow waters, which are usually close to land.
“When sea ice appears in these nearshore waters, polar bears can make hay,” Amstrup said.
But in recent years, in most summers, sea ice has receded far offshore. Amstrup says this forces the bear to drift on the ice into deep water with no prey—sometimes close to a mile deep.
Near Alaska, the polar bears in the Beaufort Sea and the Chukchi Sea are in sharp contrast.
Amstrup said that 30 to 40 miles offshore from Prudhoe Bay in the Beaufort Sea, “you are in very unproductive waters.”
Farther south in Chukchi, it is shallower, which allows walruses that feed on the bottom to thrive. He said this provided food for the polar bears.
“Because of increased productivity, Chukchi’s bears seem to be doing well,” Armstrup said. But Beaufort’s bear “gave us a really good early warning, telling us where this is going.”
Even if world leaders meet in Scotland to try to step up efforts to curb climate change, scientists monitoring sea ice and polar bears know that so much warming has already begun.
Experts say that if the negotiations are successful and all goes well, the world will likely see a large amount of sea ice in the Arctic again at the end of this century and the summer of the 22nd century. But before that, “that door was closed,” said Twila Moon, a scientist at the National Ice and Snow Data Center.
So hope is melting.
“It’s almost impossible for us to see a place where we have not reached the North Pole where there is basically no sea ice, even if we can do a lot of work to produce a lot of, much lower endothermic gas emissions,” said Moon. “Sea ice is what we are. Will see one of the things that reach some very destructive lows along this road. We can already see the impact of these on polar bears.”
© 2021 Canadian Press
