OTTAWA — Environment Minister David Anderson predicts the United States will rejoin the international effort to curb greenhouse emissions because of a growing realization that its own national security is at stake.

Anderson said he does not expect Washington to rejoin the Kyoto treaty but to launch a vigorous parallel effort to cut emissions on its own terms, using access to its market to ensure compliance by trading partners. Speaking at t he University of Ottawa on Monday, Anderson cited a Pentagon study, leaked to a British newspaper this week, as evidence of changing attitudes in Washington.

The Pentagon study says the scenario of catastrophic climate change is "plausible and would change U.S. national security in ways that should be considered immediately."

U.S. President George W. Bush pulled Washington out of the Kyoto climate treaty about three years ago, citing scientific uncertainty and the need to protect American jobs.

Since then the evidence of climate change has grown stronger, and much of the research has come from the U.S. scientific establishment, Anderson said.

"What I strongly suspect is that we will get a change in American policy soon regardless of who becomes president or who remains president."

"I suspect it is going to be very difficult for the American administration to continue with its position given the increasing evidence of this being a major, major global problem."

The Pentagon study, obtained by The Observer, predicts abrupt climate change could bring global anarchy as countries develop nuclear capability to defend food, water and energy supplies.

It says climate change "should be elevated beyond a scientific debate to a U.S. national security concern."

Anderson said Alberta's resistance to the Kyoto protocol is also fading.

"The rumblings have changed substantially in the past year."

He said the Alberta government was forced to drop its talk of penalizing companies that co-operated with the federal Kyoto compliance plan after a backlash from industry.

Industry leaders understand it doesn't make sense for each jurisdiction to develop its own plan to deal with a global problem like climate change, he said.

He recalled that a year ago Alberta "was set to sue the federal government in the highest court in the land" over Ottawa's ratification of the Kyoto treaty, but the case never materialized.

Kyoto is no longer being routinely compared to the National Energy Program of the early 1980s, which angered the West, he added.

"I'm still a whipping boy in Alberta -- fair enough, they have to have somebody to whip. But the substance of the debate is not there and the reason is straightforward -- Albertans generally speaking support climate-change measures."

He said awareness of climate change is higher in Alberta than in any other province.

The spectacular snowstorm that hit Halifax last week is one more reminder of the havoc that extreme weather can bring, he said.

No single extreme weather event can be blamed on climate change, but an increasing frequency of such events is consistent with predictions of climate scientists.