ANCHORAGE--U.S. Sen. Ted Stevens, R-Alaska, says he disagrees with a new scientific study's conclusion that the burning of fossil fuels is a major factor in climate change.

The study by the Arctic Climate Impact Assessment was commissioned by an international commission with representatives from eight countries, including the United States, as well as six indigenous groups.

Scientists who helped put together the report briefed members of the U.S. Senate Commerce Committee on Tuesday.

But he said he does not accept the conclusion the scientists reached: that the driving force behind warming is people burning coal, oil and natural gas, the fuels that produce greenhouse gases that trap heat in the atmosphere.

Stevens said there would be differences of opinion on what to do about the problem.

"But I don't think there are going to be any difference of opinion that this change is taking place and we need to take some action," Alaska's senior senator said.

Stevens' spokeswoman, Courtney Schikora Boone, said the action Stevens is taking is to fund more research about climate change.

"If you look back at the history of the globe, there's been so much cyclical global change. We want to make sure whether it is cyclical or solely man-made or if it is both," Boone said.

That approach is at odds with Stevens' fellow Republican, Arizona Sen. John McCain, who argued that a mountain of scientific evidence points to the burning of fossil fuels and that immediate action was needed to curb greenhouse gas emissions.

"Unless we address them, the people in Arizona are going to have the same problem as the people in Alaska face today," McCain said at the Tuesday hearing.

The Alaska Arctic is now warming at up to 10 times the rate of the rest of the planet, wrecking villages, melting glaciers and threatening the extinction of polar bears and ringed seals, the scientists told the committee.

Remote Alaska is at the center of the debate as a result of the scientists' conclusion that the Arctic is the first to feel effects that will be global. One reason is that when snow and ice melt, the exposed, bare ground absorbs more heat.

"If you live in Alaska or you live in the Arctic, the things that are happening are of profound importance," said Robert Correll, a senior fellow with the American Meteorological Society and leader of the scientific team that produced the report.

Greenhouse gases remain in the atmosphere for 100 years, Correll said. So it will be difficult to slow the progress of global warming.

"It's like putting the brakes on a supertanker," he said.

About 300 scientists participated in putting the study together, including scientists from Alaska.

"The strength of the trends and the patterns of change that have emerged in recent decades indicate that human influences, resulting primarily from increased emissions of carbon dioxide and other greenhouse gases, have now become the dominant factor," it says.

The Arctic Council will meet next week in Iceland to consider what to do about climate change.

President Bush has opposed curbing greenhouse-gas emissions, arguing that the science is not clear and it would hurt the economy.