Roughly one-third of the world's gas reserves and 13 per cent of its oil reserves lie north of the Arctic Circle, estimate U.S. Geological Survey researchers who suggest most of the gas is in Russian territory.

Russia could benefit from increasing its existing gas reserves, currently the biggest in the world. But the oil estimate is small, compared with known reserves in major petroleum-exporting countries, and is unlikely to shift trade patterns greatly, the researchers say.

Discoveries of oil and gas in general could still have economic significance to Arctic nations, such as Canada, the U.S., Denmark/Greenland, Norway and Russia.

If oil were found off Greenland in significant quantities, for example, it could mean the difference between whether Greenland becomes independent from Denmark or not, says geologist Donald Gautier.

Gauthier and his colleagues published the results of their study Thursday in the journal Science, calling it the first release of detailed maps estimating reserves in the region.

The USGS estimates there are three years' worth of reserves in the area at the current rate of consumption, but Gauthier cautioned that his team did not take into account the cost and difficulty of getting to these reserves.

Incremental production expected

"If these resources were found, they would not be found all at once. They would be found incrementally and they would be produced incrementally," he said in a Science podcast.

The study comes at a time when Arctic nations are jostling for jurisdiction in the region.

Under the UN Convention on the Law of the Sea, which Canada ratified in 2003, coastal countries control the resources under their coastal waters up to 200 nautical miles from shore.

Under the treaty, a country's territory can be expanded much further if it can prove the ridges and rock formations under the water are connected to its continental shelf.

But it's a race against time. Countries have 10 years from when they sign the treaty to submit their scientific data to a UN commission. Canada has just four years left — until 2013.

Meanwhile, Gauthier and his fellow researchers expressed concerns about the environmental impact of removing gas and oil from the Arctic.

"The potential for resource development is of increasing concern to the Arctic nations, to petroleum companies and to all concerned about the region's fragile environments," the authors write.

"These concerns have been heightened by the recent retreat of polar ice, which is changing ecosystems and improving the prospect of easier petroleum exploration and development."