High energy prices are paving the way for decades old proposals.

Of the two lines, the Alaska Gas Pipeline is the behemoth. Its most likely route would stretch 1,700 miles from Alaska's Prudhoe Bay to Canada's Alberta province. The line would cost $20 billion and take a decade to build, but the project has picked up momentum under the whip of Alaska Gov. Frank H. Murkowski (R) and $18 billion in loan guarantees approved last year by Congress.

The second line, the Mackenzie Valley Pipeline, would start 250 miles east of the Alaska line, on Canada's portion of the Beaufort Sea. It would snake 800 miles through forests of spruce and pine along the Mackenzie River -- one of the world's longest with no bridge or dam. This all-Canada route would cost $6 billion and is predicted to take three years to complete once construction begins.

I can see one free market argument for the loan guarantees: Most of the risk is political. If the government was stuck with the bill for a partially completed pipeline that was stopped due to environmentalist opposition then the government would be less likely to bow to environmentalist pressures to stop the project.

Environmentalists are opposed but see at least one pipeline as inevitable. I figure they both will get built. Declining US natural gas production in the lower 48 states makes the economics too attractive and both the US and Canadian publics do not want high heating and electric bills.

The bigger footprint, after the construction crews have left, will be in opening the mineral-rich area to further exploration and development.

Mostly for that reason, some environmentalists favor the Alaska Pipeline, which follows the route of the existing oil pipeline and Alaska Highway.

"We think it's the lesser environmental evil," said Stephen Hazell, a director of the Sierra Club of Canada. Environmental groups have largely bowed to the inevitability of at least one of the projects.

The Canadian pipeline is being delayed by negotiations with native tribes. Environmentalists are more opposed to the smaller Canadian project because it would open up an area for development that currently is hard to reach. The roads built in Alaska for the oil pipeline could be used for the Alaskan natural gas pipeline and so won't do as much to make inaccessible areas accessible.

The environmentalists also fear the Canadian natural gas will be used as an energy source for harvesting oil from the Alberta tar sands. About that fear: The environmentalists who want to bring an end to the age of fossil fuels should spend a lot more time promoting the idea of a broad research effort to develop cleaner technologies. Their fight against fossil fuels is doomed because as soon as prices rise high enough the majority of the public will swing around toward supporting more pipelines and drilling. Fossil fuels use will not get regulated out of existence. Only lower prices for other energy sources will bring an end to fossil fuels use.