RESOLUTE, Nunavut — Bob Hudson says he has played in the Rose Bowl, jumped out of airplanes, scuba dived off Fiji and stalked bighorn sheep in the Rockies. But for all the excitement of his 67 years, there was one thrill he still craved: hunting polar bear in the high Canadian Arctic.

He sold his beloved Jaguar XKE on eBay for $26,000 to do it. After heavy wind and snow ruined his hunt in April, he took another $14,000 out of his retirement account for a return trip.

“Life is short,” Mr. Hudson joked. “The last check you write should be to the undertaker, and it should bounce.”

Mr. Hudson, a McDonald’s franchise owner from Oxford, Miss., got his trophy: a nine-foot bear bagged with a single shot from 30 yards. But the future of the hunt is far less certain for those who may want to follow his tracks.

Polar bear hunting has gotten caught up in the larger debate over global warming. Scientists and environmentalists are pushing for measures to protect the animal, whose most immediate threat, they say, is not hunters, but loss of habitat.

As its icy environs shrink, the polar bear has, improbably perhaps, become the new poster face of Arctic vulnerability. Move over, baby seal.

“People care about polar bears — they’re iconic,” noted Kassie Siegel, a lawyer at the Center for Biological Diversity. “The reality of the threat to polar bears is helping to get the word out,” she said, about the effects of climate change.

Her group, along with Greenpeace and the Natural Resources Defense Council, filed a petition with the United States government to list the polar bear as threatened as a way to push the American authorities to control greenhouse gas emissions, like carbon dioxide from cars.

The message has alarmed American polar bear hunters, who could be barred from bringing their trophies home from Canada, the only country from which they can legally do so. It has also run up against unbending opposition from local communities of Inuit, also known as Eskimos, and the Nunavut territorial government, which has expanded sport hunting in recent years.

For polar bear hunters, who are typically wealthy Americans past 50, the trip in a caribou-skin suit on a dog sled is an age-defying passage in a land of disorienting beauty, where the sun does not set for months and nothing but a dreamy blue strip of sky distinguishes ice from cloud.

For their Inuit guides, the sport hunt is a preserver of tradition and a welcome source of income in snowbound settlements where jobs are almost as scarce as trees.

“The environmentalists can say no more hunting of polar bears, but we’ll keep killing them,” said David Kalluk, 65, a Resolute village elder. “That’s the way it has been for generations and generations.”

But while the hunt may be unchanging, the globe’s climate is not.

Global warming and over-hunting could diminish the polar bear population by at least 30 percent in coming decades, the International Union for Conservation of Nature and Natural Resources, a network of 10,000 scientists, predicted in May.

“Given what the climate models predict for continuing warming and melting of sea ice, the whole thing leads to an extinction curve,” said Peter Ewins, director of the World Wildlife Fund Canada’s Arctic Conservation Program. “And it’s not a question of if, it’s a clear question of when.”

Hunting, when insufficiently controlled, he added, “has the potential to really compound the problem.”

Nunavut increased its annual hunting quotas by 29 percent last year — to 518 kills, an increase of 115 — saying that Inuit hunters were actually seeing an increase in polar bear populations.

That impression, some scientists and environmentalists say, is simply a matter of the bear’s greater visibility, as shrinking ice pushes them closer to Inuit communities.

Those experts tick off a list of stresses on the polar bear: Global warming is melting the bear’s icy migration routes, critical for breeding and catching seals for food, around Hudson Bay and Alaska. Poaching is threatening populations in Russia. Pollution is causing deformities and reproductive failures in Norway.

Other experts see a healthier population. They note that there are more than 20,000 polar bears roaming the Arctic, compared to as few as 5,000 40 years ago, before Canada, Denmark, Norway, the Soviet Union and the United States agreed to strong restrictions on trophy hunting in the 1970’s.

Some scientists say northern polar bear populations are safe from global warming, and those farther south might well find ways to adapt or simply migrate north.

Mitchell Taylor, manager of wildlife research for the Nunavut government, said warming trends had so far seriously affected only western Hudson Bay, just one of 20 areas where polar bears live. He acknowledged that over-hunting could be a problem in Baffin Bay, between Canada and Greenland.

“In other areas, polar bears appear to be overabundant,” he added. “People have to quit thinking of polar bears as one big continuous mass of animals that are all doing the same thing.”

In Canada, a committee of scientists recommended in 2003 that the government list the polar bear as a species of “special concern,” which would require federal monitoring. But the environment minister sent the recommendation back, under pressure from Nunavut officials, who complained that traditional Inuit knowledge had been ignored.

“The bears are getting smaller, their reproduction is getting less effective, and I have heard about data that show their survival is in decline,” said Marco Festa-Bianchet, a biology professor at the University of Sherbrooke in Quebec who recently stepped down as chairman of the committee.

He said the panel would complete a new report in 2008. In the meantime, he said, “the fact that the hunting quota has been increased clearly increases the level of concern.”

Meanwhile, officials at the United States Fish and Wildlife Service expect to rule in December on whether the polar bear should be designated as threatened under the Endangered Species Act. That designation is a real possibility, they said, at least for several of the 13 areas where Canadian bears now roam.

The possibility that wealthy American hunters may stop coming north has raised concern among Inuit people and politicians, even those who also decry global warming as a threat to their way of life.

Nancy Karetak-Lindell, an Inuit member of the House of Commons, called the effort by American environmentalists “a little intrusive and very disrespectful.”

In an interview, she added that the bear hunt “is more than a way of life, it’s a way of survival.”

In Resolute, a snow-swept hamlet of shacks hugging a salty ice-packed Arctic channel, Inuit villagers hold an annual lottery to see who will get the permits to kill the local quota of 35 bears a year.

Fifteen of those bears will be consumed locally, as food and to make rugs, mattresses, wind pants and mittens. The 20 other permits are sold to American hunters.

With each permit, or tag, worth nearly $2,500, that means a fast infusion of nearly $50,000 a year into the community, on Cornwallis Island some 500 miles above the Arctic Circle. On top of that, the guides earn almost $8,000, and their assistants another $4,500, per hunt.

If the Americans stop coming, the guides say, they will seek other foreign hunters or kill the entire quota for themselves.

Demand is already pent up. Outfitters who organize the hunting trips say there is a three-year waiting list for Americans who want to go.

Hunters say few experiences can compare with the sensation of sighting a bear, then watching the Inuit guides release their huskies to surround and confuse the prey long enough for the hunters to shoot it.

“This is my Disney World,” said Manuel Camacho, a 60-year-old urologist from Miami, before he set out on his hunt in May.

Once on the ice, the hunt can be suspended for days at a time by frosty fog. There is little to do but drink instant coffee, eat macaroni and cheese, and doze off on a shedding caribou skin. The silence is broken only by the soft howl of a sled dog or the hum of a gas stove.

The landscape is stark, yet awesome. The lack of color — or anything — makes even the smallest sight exhilarating: a black dot in the distance (a seal popping out of the ice), a wolf track, the passing of a raven, or a mother bear rambling with her cub.

The adventure is most often one within the mind, the polar panorama providing a blank canvas to be filled in by the imagination.

For Dr. Camacho, a Cuban exile and Vietnam veteran who has hunted all over the world, his thoughts wandered to his former wife and ex-girlfriends, opportunities seized, opportunities lost.

“One moment I am thinking of medical school, then click off and look at the dogs or an iceberg,” he said at the end of one day hunting. “And then click again and my mind drifts to experiences I have had in Central America and Africa.”

For the hunter and the hunted, it is a race against time. After waiting several years, Dr. Camacho told his outfitter that he did not want “to wait till I am in wheelchair” to hunt a polar bear.

“It’s tickling to think I could be the last American hunter who brings in a polar bear trophy,” he said. “I might just squeak by.” The very next day, he shot one.