The heat is on

ABOARD THE HMCS GLACE BAY -- The pitching Navy ship had just crossed the Arctic Circle when a seasoned crew member lathered whipped cream onto his mates' faces. Another dropped a Tabasco-dipped cherry into each mouth. And then, yet another poured frigid Arctic sea water over every shivering head, christening each as a ''bluenoser" -- someone who has crossed the imaginary line into the vast, icy circle.

The trip was a baptism of sorts for the Canadian Navy, too. After decades of neglect, Canada is launching an all-out effort to protect its North. The Glace Bay was the first Navy ship to visit Cape Dorset and towns in Hudson Bay in nearly 30 years. Its mission: To reconnect with local Inuit who form the country's first northern line of defense.

This frigid area, with its barren landscape stretching for thousands of miles, is suddenly worth fighting for, Canadian officials say, because of global warming. The Arctic sea ice cap shrank this summer to the smallest size ever measured, and some scientists say summer sea ice could disappear entirely by the end of this century.

The melting and climate change that are widely predicted to be a disaster elsewhere in the world -- creating monstrous hurricanes, killing crops, and redrawing coastlines -- appears to be creating a boom for the northern reaches of Canada.

''Global warming has put the Canadian North back on the map," said Colonel Norm Couturier, commander of Canadian Forces Northern Area.

Better drilling and mapping technology was already pushing the oil and gas industry northward. But the warming -- which many scientists believe is being caused primarily by man-made releases of carbon dioxide and other gases that trap heat in the atmosphere -- is propelling even more companies to explore under the ice, where as much as a quarter of the world's supply of gas and oil may lie.

And shipping companies have begun to see gold in the melting ice, which within several decades could allow boats to shave thousands of miles off their journeys between the Atlantic and the Pacific oceans at least a few months a year. Normally, boats going from London to Tokyo, or New York to San Francisco, must trek south through the Panama Canal.

All this potential has created an international race to claim the new resources and has put the Canadians on guard.

Canadians say the Northwest Passage is theirs and want control to prevent environmental catastrophes from oil tankers that may spring leaks. US officials say the passage is an international waterway. A boundary dispute between the United States and Canada in the resource-rich Beaufort Sea above northeast Alaska is percolating again. And in what has become a symbolic issue over sovereignty, both Canada and Denmark sparred this summer over the ownership of a tiny uninhabited island off Greenland that has little, if any, economic or strategic value.

Canada doesn't expect to win its battle with military might. Notoriously underfunded -- the Navy doesn't even own an icebreaker -- Arctic military patrols are largely conducted by 1,500 Inuit Canadian Rangers, equipped with World War II-era rifles and red baseball caps, tents, cooking gear, and lamps.

Instead of using force, the country is attempting to build up a legal case to prove that it owns, occupies, and patrols its vast northern region. Canadian scientists are carefully mapping undersea resources on the continental shelf that other countries may want to claim for themselves. Defense officials are tracking northern ship traffic and unmanned planes are flying surveillance missions over the region.

The Glace Bay's five-week visit was part of that strategy -- it made 17 stops to reconnect with northern communities to make them feel part of the larger battle and practice maneuvers.

''We need to become smarter up here," said Glace Bay captain Scott Healey, as the ship glided past a house-sized iceberg.

The ship's two-day stop in Cape Dorset, on a rocky island off the southern tip of Baffin Island, illustrated the promise and problems of the thaw, and Canada's challenge in protecting it.

Nestled between rocky mounds, the isolated community's dusty roads end at the vast expanses of tundra and water surrounding it. The only way to get to Cape Dorset, population about 1,300, is by plane or sea.

Once the Glace Bay anchored off the community's coast, crewmembers loaded into inflatable rafts and motored to shore. Little children tugged at their jackets looking for sweets. Local men organized village tours to the naval ship, the first one many residents had ever seen. Women in white parkas -- with the occasional baby poking out of a fur-lined hood -- uncovered rag-wrapped stone sculptures of polar bears and musk ox, and whispered bargains in crewmembers' ears.

Tourism could increase here with the melting, locals say. Cape Dorset is one of the best-known artistic communities in the Arctic, renowned for its hand-carved stone sculptures and prints that can fetch thousands of dollars in New York and Boston. Today, about five ships visit the community each year, with passengers infusing the town with as much as $40,000 per visit, locals say. If the area were passable for longer, maybe more cruise ships would come.

''It could be good," said Sarah Oshutsiaq, 27, a Cape Dorset resident.

Yet in Cape Dorset as elsewhere, there are worries over the melting, too. Many animals use the ice as a platform to hunt and as it melts, they could starve. Local Inuit say they cannot find as many animals to hunt as they once did. Warmer waters may mean fish locals eat may be harder to catch as they move into more northern waters. Some studies have shown that polar bears, which hunt their prey on sea ice during the winter, are not storing enough fat to make it through the lengthening summer.

Chain-smoking 21-year-old Ottokie Aningmiuq, a Cape Dorset hunter and deputized ranger, remembers how he used to walk on the sea ice as a child to trick or treat on Halloween. Now, it's December before that seawater freezes solidly enough for him to step on it.

''I do not know if the melting is good or bad," said Aningmiuq as he sped his motorboat off Cape Dorset on a seal hunt to search for food that the entire community will share.

''The ice is changing," he said. ''We have to wait and see what happens."