了解今日课堂：

"北极熊之都"的北极熊未来何在?

3,000 Miles From Glasgow, a Town and Its Polar Bears Face the Future

BINYAMIN APPELBAUM, DAMON WINTER

2021年11月12日

第一段：

CHURCHILL, MANITOBA — This is not another story about saving Hudson Bay's polar bears. It's too late for that. This is a story about what comes next for a small town that bills itself as the Polar Bear Capital of the World.

In Churchill, an isolated town perched on the southern edge of the Arctic, climate change is not a looming danger. It imbues daily life. It is broken sewer lines and taller trees, longer summers and bigger snowstorms and moose where caribou used to go. Most of all, it is the fear that Americans won't come visit anymore.

第二段

In 2014, a Canadian doctor visiting Churchill from southern Ontario took a photograph of climate change. It shows a red fox holding an arctic fox in its mouth, the blood of the smaller creature staining its snow-white fur.

Warmer weather is endangering Arctic species, in part by opening the gates for other animals, like red foxes, wolves and brown bears, as well as a host of smaller species, to move north. "We haven't found anything that isn't changing" in the Hudson Bay ecosystem, said David Barber, a professor at the University of Manitoba who studies climate change as scientific director of the Churchill Marine Observatory. "From the viruses and the bacteria right up to the whales, every single thing is being affected by climate change."That includes the local celebrities: Ursus maritimus, or polar bears.

The big white bears live out of rhythm with their southern cousins. In the winter, instead of sleeping, they roam across the surface of the frozen bay, looking for ringed seals. In the summer, when the ice melts, they rest on shore. Every year around this time, several hundred polar bears congregate around Churchill, waiting for the ice to form.

While the polar bears are on land, people in Churchill are careful to make wide turns around street corners. They avoid walking alone at night. They guard their trash with the kind of care usually reserved for things that are valuable. Everyone has a story about a close encounter. Joseph Michel Boudreau, 74, told me that one morning he made the mistake of cooking bacon without turning on the stovetop vent. A bear put a paw through a front window. Mr. Boudreau went out the back door.

The bears are not just a nuisance, however. They are also the mainstays of the local economy. Great White Bear Tours, Lazy Bear Expeditions and other companies with similar names cater to an annual influx of wealthy tourists, carrying them in big-wheeled buses to the shoreline, where the bears congregate. The warnings about bears in town add a little excitement to the experience.

Churchill is stuffed with bearskins, but these days, every effort is made to keep the animals alive. Bears that don't behave used to be shot. Now they're trapped, taken to "bear jail" — an airport hangar with reinforced cells — and eventually airlifted about 70 kilometers (about 43 miles) north, where there are even fewer people.

第三段：

One immediate impact of global warming is that the bears are spending more time around Churchill as the sea ice forms later in the year and melts earlier. On land, polar bears lose about 1 kilogram (2.2 pounds) of their weight each day. As ice season shrinks, the bears face the double pain of fewer days of hunting and more days of fasting. Between 1980 and 2019, the weight of the average pregnant polar bear in the Churchill region declined by 15 percent, according to Nick Lunn, a Canadian government scientist. New births are in decline. The number of polar bears in western Hudson Bay fell by 30 percent from 1987 to 2016, and some experts think the population already is in terminal decline.

Some bears may survive, at least for a time, by moving farther north. But over the coming decades, if greenhouse gas emissions continue to build at the current pace, the disappearance of polar bears from the Hudson Bay region is inevitable, according to a 2020 study conducted by scientists at Polar Bears International, a research and advocacy group. Steven Amstrup, its chief scientist, said it's not too late. "I am confident that holding the global temperature rise below two degrees Celsius will preserve polar bears in parts of their current range," he said. That is the goal nations set at the Paris climate meetings in 2015. But the commitments that nations have made are inadequate to achieve that goal. Scientists estimate global temperatures are on pace to rise by roughly three degrees Celsius above the preindustrial norm by the end of the century.

In his 2019 book, "The Wizard and the Prophet," the science writer Charles C. Mann described a long-running argument between those who believe humans can survive in the long term only by accepting the limits of nature and those who believe humans can survive by reshaping nature. Wittingly or otherwise, we are placing our chips in the second basket.