The polar bear, the largest bear of them all and a fearsome predator, is the poster animal of climate change, and for good reason: While most threatened animals, such as the rhinoceros, are victims of localized threats like poaching or human encroachment, the polar bear is threatened most gravely by global emissions of greenhouse gases.

A polar bear was the star of Al Gore’s celebrated 2006 film on climate change, “An Inconvenient Truth,” and it has its own conservation organization, Polar Bears International, which has designated Feb. 27 as International Polar Bear Day. But celebrity can be a double-edged sword in debates over something as contentious as climate change, as Erica Goode noted in an article in the New York Times on Sunday.

Using the bear as an icon to raise consciousness and funds, she wrote, does more than arouse support from conservationists. It also presents a ready target from climate change deniers who are only too willing to use inevitable uncertainties about the polar bear’s actual numbers to challenge the facts of climate change. Those facts are worth repeating.

The polar bear is basically designed to convert seal fat into insulation and flesh. Weighing up to 1,500 pounds, the animal has survived for millenniums by prowling the edges of Arctic sea ice waiting for seals to pop up for air. With the Arctic warming twice as fast as any other part of the earth, and with the ice seemingly in permanent retreat, the bears have been left stranded on land desperately seeking other things to eat.

This year was particularly bad. The freeze came late; the extent of Arctic sea ice was less this November than in any previous November. Some parts of Hudson Bay, whose western stretches were once home to 1,200 polar bears, were still ice-free at the end of November.

Some polar bears that have become “climate refugees” now descend on the Alaskan Arctic settlement of Kaktovik to scavenge the skeletons of whales dumped there by whale hunters. The gathering has helped bring tourists to Kaktovik to get a firsthand glimpse of the bears.

To scientists, these thin and hungry bears are a sign of a species in danger. To climate change deniers, they are evidence that the bears are adapting just fine. Concrete numbers are indeed elusive, given the paucity of information about a species in so remote a region.

But to scientists watching the bears in Kaktovik, there is no question that the bears are not picking whale bones by choice. They are there because their natural habitat is in decline, a fate that awaits untold numbers of other bears.