YOKOSUKA, Japan — To the world’s military leaders, the debate over climate change is long over. They are preparing for a new kind of Cold War in the Arctic, anticipating that rising temperatures there will open up a treasure trove of resources, long-dreamed-of sea lanes and a slew of potential conflicts.

By Arctic standards, the region is already buzzing with military activity, and experts believe that will increase significantly in the years ahead.

Last month, Norway wrapped up one of the largest Arctic maneuvers ever — Exercise Cold Response — with 16,300 troops from 14 countries training on the ice for everything from high intensity warfare to terror threats. Attesting to the harsh conditions, five Norwegian troops were killed when their C-130 Hercules aircraft crashed near the summit of Kebnekaise, Sweden’s highest mountain.

The U.S., Canada and Denmark held major exercises two months ago, and in an unprecedented move, the military chiefs of the eight main Arctic powers — Canada, the U.S., Russia, Iceland, Denmark, Sweden, Norway and Finland — gathered at a Canadian military base last week to specifically discuss regional security issues.

None of this means a shooting war is likely at the North Pole any time soon. But as the number of workers and ships increases in the High North to exploit oil and gas reserves, so will the need for policing, border patrols and — if push comes to shove — military muscle to enforce rival claims.

The U.S. Geological Survey estimates that 13 percent of the world’s undiscovered oil and 30 percent of its untapped natural gas is in the Arctic. Shipping lanes could be regularly open across the Arctic by 2030 as rising temperatures continue to melt the sea ice, according to a National Research Council analysis commissioned by the U.S. Navy last year.

What countries should do about climate change remains a heated political debate. But that has not stopped north-looking militaries from moving ahead with strategies that assume current trends will continue.

Russia, Canada and the United States have the biggest stakes in the Arctic. With its military budget stretched thin by Iraq, Afghanistan and more pressing issues elsewhere, the United States has been something of a reluctant northern power, though its nuclear-powered submarine fleet, which can navigate for months underwater and below the ice cap, remains second to none.

Russia — one-third of which lies within the Arctic Circle — has been the most aggressive in establishing itself as the emerging region’s superpower.

Rob Huebert, an associate political science professor at the University of Calgary in Canada, said Russia has recovered enough from its economic troubles of the 1990s to significantly rebuild its Arctic military capabilities, which were a key to the overall Cold War strategy of the Soviet Union, and has increased its bomber patrols and submarine activity.

He said that has in turn led other Arctic countries — Norway, Denmark and Canada — to resume regional military exercises that they had abandoned or cut back on after the Soviet collapse. Even non-Arctic nations such as France have expressed interest in deploying their militaries to the Arctic.