The bears that come here are climate refugees, on land because the sea ice they rely on for hunting seals is receding
Polar bears’ path to decline runs through Alaskan village
COME fall, polar bears are everywhere around this Arctic village, dozing on sand spits, roughhousing in the shallows, padding down the beach with cubs in tow and attracting hundreds of tourists who travel long distances to see them.
At night, the bears steal into town, making it dangerous to walk outside without a firearm or bear spray. They leave only reluctantly, chased off by the polar bear patrol with firecracker shells and spotlights.
On the surface, these bears might not seem like members of a species facing possible extinction.
Scientists have counted up to 80 at a time in or near Kaktovik; many look healthy and plump, especially in early fall, when their presence overlaps with the Inupiat village’s whaling season.
But the bears that come to Kaktovik are climate refugees, on land because the sea ice they rely on for hunting seals is receding.
The Arctic is warming twice as fast as the rest of the planet, and the ice cover is retreating at a pace that even the climate scientists who predicted the decline find startling.
Much of 2016 was warmer than normal, and the freezeup came late. In November, the extent of Arctic sea ice was lower than ever recorded for that month. Though the average rate of ice growth was faster than normal for the month, over five days in midNovember the ice cover lost more than 19,000 square miles (50,000 square metres), a decline that the National Snow and Ice Data Center in Colorado called “almost unprecedented” for that time of year.
In the southern Beaufort Sea, where Kaktovik’s 260 residents occupy 1 square mile on the northeast corner of Barter Island, sea ice loss has been especially precipitous.
The continuing loss of sea ice does not bode well for polar bears, whose existence depends on an ice cover that is rapidly thinning and melting as the climate warms. As Steve Amstrup, chief scientist for Polar Bears International, a conservation organisation, put it: “As the sea ice goes, so goes the polar bear.”
An imperfect symbol
The largest of the bear subspecies and a powerful apex predator, the charismatic polar bear became the poster animal for climate change.
Al Gore’s 2006 film, An Inconvenient Truth, which depicted a lone polar bear struggling in a virtually iceless Arctic sea, tied the bears to climate change in many people’s minds. And the US government’s 2008 decision to list polar bears as threatened under the Endangered Species Act – a designation based in part on the future danger posed by a loss of sea ice – cemented the link. But even as the polar bear’s symbolic role has raised awareness, some scientists say it has also oversimplified the bears’ plight and unwittingly opened the door to attacks by climate denialists.
“When you’re using it as a marketing tool and to bring in donations, there can be a tendency to lose the nuance in the message,” said Todd Atwood, a researcher at the US Geological Survey’s Alaska Science Center. “And with polar bears in particular, I think the nuances are important.”
Few scientists dispute that in the long run – barring definitive action by countries to curb global greenhouse gas emissions – polar bears are in trouble, and experts have predicted that the number will decrease with continued sea ice loss. A 2015 assessment for the International Union for Conservation of Nature’s Red List projected a reduction of more than 30 percent in the number of polar bears by 2050, while noting that there was uncertainty about how extensive or rapid the decline of the bears – or the ice – would be.
But the effect of climate change in the shorter term is less clear cut, and a populationwide decline is not yet apparent. Nineteen subpopulations of polar bears inhabit five countries that ring the Arctic Circle – Canada, the US, Norway, Greenland and Russia.
Of those, three populations, including the polar bears in the southern Beaufort Sea, are falling in number.
But six other populations are stable. One is increasing. And scientists have so little information about the remaining nine that they are unable to gauge their numbers or health.
In their analysis, the researchers who conducted the Red List assessment concluded that polar bears should remain listed as “vulnerable”, rather than be moved up to a more endangered category.
Yet numbers aside, scientists are seeing other, more subtle indicators that the species is at increasing risk, including changes in the bears’ physical condition, body size, reproduction and survival rates. And scientists have linked some of these changes to a loss of sea ice and an increase in ice-free days in the areas where the bears live.
Climate-change denialists have seized on the uncertainties in the science to argue that the bears are doing fine and that sea ice loss does not pose a threat to their survival. But biologists say there is little question that the trend, for both sea ice and polar bears, is downward. The decline of a species, they note, is never a steady march to extinction.
“It’s not going to happen in a smooth, linear way,” said Eric Regehr, a biologist at the federal Fish and Wildlife Service.
From sea to shore
A dozen polar bears pick through the bone pile that sits just outside town. Men from the whaling crews had dumped the carcass of a bowhead whale on the pile earlier in the day. As two visitors watch from the safety of a pickup truck a few hundred metres away, the bears devour the leftover meat and blubber.
The Inupiat, who have been whaling in Kaktovik for thousands of years, believe that a whale gives itself to the crew that captures it. Once the animal’s body is pulled to shore, water is poured over it to free its spirit.
Even a few decades ago, most polar bears in the south- ern Beaufort Sea remained on the ice year-round or, if they did come to shore, stopped only briefly. The sea ice gave them ready access to seals, the staple of their high-fat diet.
But as the climate has warmed, the spring thaw has come earlier and the fall freeze later. The pack ice that was once visible from Kaktovik even in summertime has retreated hundreds of miles offshore, well beyond the southern Beaufort’s narrow continental shelf. The edge of the pack ice is now over deep water, where seals are few and