Departing US president grasps at resources beyond Alaska – but scientists warn the move could accelerate global warming

The United States has declared its intention to exploit the vast oil and mineral wealth hidden below the Arctic circle by extending its "sovereign rights" over the seabed.

A detailed policy directive – issued a week before George Bush quits the White House – makes explicit the extent of US ambitions in the polar region beyond Alaska.

"The United States is an Arctic nation, with varied and compelling interests in that region," the document – National Security Presidential Directive 66 – states in its introduction, while acknowledging "a growing awareness that the Arctic region is both fragile and rich in resources".

There is a qualified acceptance of "the effects of climate change and increasing human activity in the Arctic region" but the main thrust of the paper concerns how the US can tap potential energy resources.

One of the main obstacles to staking a claim on the Arctic seafloor has been opposition in the Senate to ratification of the United Nations' 1982 Law of the Sea Convention.

The White House implicitly urges senators to overcome residual suspicions of the UN in the interests of national security, environmental protection and business opportunity. The US is one of the few nations not to have signed up to the agreement which allows countries to extend their control of the seabed from 200 miles to up to 350 miles beyond their coastline.

Ratification, it says, would define "with certainty the area of the Arctic seabed and subsoil in which the United States may exercise its sovereign rights over natural resources such as oil, natural gas, methane hydrates, minerals, and living marine species… "

Methane hydrates are solidified gases formed under great pressure and at low temperatures on the seafloor. They have been identified as an extensive energy source in future, although some environmentalists have warned they could trigger runaway global warming.

The directive calls for "all actions necessary to establish the outer limit of the continental shelf appertaining to the United States, in the Arctic and in other regions, to the fullest extent permitted under international law."

The paper sounds a note of scepticism about the extent of global warming. "High levels of uncertainty remain concerning the effects of climate change and increased human activity in the Arctic," it remarks. "An understanding of the probable consequences of global climate variability and change on Arctic ecosystems is essential to guide the effective long-term management of Arctic natural resources and to address socioeconomic impacts of changing patterns in the use of natural resources."

Two years ago a Russian submarine planted a flag on the seabed under the Arctic ice, intensifying the race for offshore Arctic resources. The Russian government has commissioned detailed marine, geological work to determine the external border of the Russian continental shelf in the Arctic Ocean. It is due to be completed by 2011.

The US and Canada still have an unresolved boundary in the Beaufort Sea, north of Alaska, an area thought to be rich in oil and natural gas deposits. The new US policy is binding on future administrations until replaced.

Britain has signalled that it will have lodged five claims on the Atlantic seabed with UN's Commission on the Limits of the Continental Shelf by May this year. Its latest submission, covering the area Hatton/Rockall basin west of Scotland, is due to be handed in to the UN offices in New York shortly.