As ice caps shrink around them, Inuit activists are making an international case out of Washington's alleged indifference to global warming. But the Bush administration is standing by its refusal to negotiate long-term limits on "greenhouse gases."

A two-week U.N. climate conference, attended by more than 180 nations, enters its final two days Thursday with little prospect for consensus on a key item — mandatory cutbacks beyond 2012 in carbon dioxide and other emissions whose buildup in the atmosphere is expected to disrupt the global climate.

The climate is already changing in the Arctic, where an international study last year found average winter temperatures have increased as much as 7 degrees over 50 years. Permafrost is thawing, and the extent of Arctic Sea ice is shrinking, imperiling polar bears and other animals.

The warming threatens "the destruction of the hunting and food-gathering culture of the Inuit in this century," said Paul Crowley of the Inuit Circumpolar Conference, representing 155,000 Inuit of Canada, Greenland, Russia and the United States, where they are known as Eskimos.

On Wednesday, the Inuit group submitted a petition to the Inter-American Commission on Human Rights, an investigative arm of the Organization of American States in Washington, "seeking relief from violations resulting from global warming caused by acts and omissions of the United States" — the world's biggest emitter of greenhouse gases.

The northern natives — 63 petitioners are named from all Inuit regions — seek a declaration that their human rights are being violated, putting political pressure on the U.S. government to reduce emissions.

The Montreal meeting, attracting almost 10,000 delegates, environmentalists, business representatives and others, is the first annual U.N. climate conference since the Kyoto Protocol took effect last February, requiring 35 industrialized countries to curb emissions of carbon dioxide and five other gases that act like a greenhouse trapping heat in the atmosphere.

Among major developed nations, only the United States and Australia reject that agreement, worked out in 1997 in Kyoto, Japan, and designed to produce an average 5 percent reduction of emissions below 1990 levels by 2012.

Under the protocol, the Kyoto nations must begin talks now on emissions controls after 2012.

Canadian Environment Minister Stephane Dion, looking for a compromise route that would draw the United States into the emission-controls regime, this week proposed a plan for "discussions to explore and analyze approaches for long-term cooperative action to address climate change," with a deadline for agreement by 2008.

But the Bush administration rejected the Canadian bid, saying it prefers to deal with other governments on a bilateral or regional basis, and it favors voluntary approaches. Chief U.S. delegate Paula Dobriansky pointed to $3-billion-a-year U.S. government spending on research and development of energy-saving technologies.

"We also believe firmly that negotiations will not reap progress, as indicated, because there are differing perspectives," said Dobriansky, a U.S. undersecretary of state.

President Bush rejected the Kyoto Protocol in 2001, saying limiting fuel-burning would crimp the U.S. economy, and complaining that fast-growing economies of developing countries such as China and India weren't targeted under the 1997 accord.

Dion suggested acceptable language might still be found to get the Americans on board. Closed-door talks "have been frank and productive," he told delegates at Wednesday's open session. "There is an urgent need to send a signal to the world about the future."

But a leading U.S. expert on the Kyoto process was pessimistic.

"I'm not hopeful for any movement by the United States," said Alden Meyer of the Union of Concerned Scientists. What's more realistic, he said, is a process by which China, India, Brazil and other developing powers might be brought in, "without the U.S. at the table," to make concessions on energy emissions.

A broad scientific consensus agrees that carbon dioxide in the atmosphere, byproduct of automobile engines, power plants and other fossil fuel-burning industries, has contributed significantly to the past century's global temperature rise of 1 degree.

In October, NASA climatologists projected from thousands of temperature readings that 2005 would end as the warmest year globally since records were first kept in the mid-19th century.