Secretary of State Condoleezza Rice this morning called for a "revolution in energy technology" to meet the challenge of global warming during the opening of a two-day conference here in Washington.

Speaking in the State Department's Loy Henderson Conference Room to an audience of a few hundred, which included delegations from 17 countries, Miss Rice reassured world leaders that “the United States takes climate change very seriously."

"We are both a major economy and a major emitter. Climate change is a global problem and we are contributing to it, therefore, we are prepared to expand our leadership to address the challenge," Miss Rice said.

The U.S. conference has been called the "major emitters conference" because it includes the countries with the largest economies and biggest carbon dioxide emissions.

President Bush organized the conference, which he will address tomorrow, to shape the debate over how to address global warming. The Bush administration wants to push the global community toward a broad spectrum of solutions that are business-friendly and, they say, more effective than a simple carbon emissions cap.

Miss Rice said that global warming is a "complex matter" that "cannot be dealt with effectively as an environmental challenge alone," but requires an "integrated response."

"If we stay on our present path, we face an unacceptable choice: Either we sacrifice global economic growth to secure the health of our planet or we sacrifice the health of our planet to continue with fossil-fueled growth. This is a choice that we must refuse to make," Miss Rice said.

"Instead, we must cut the Gordian knot of fossil fuels, carbon emissions, and economic activity. This current system is no longer sustainable, and we must transcend it entirely through a revolution in energy technology," she said.

Yvo de Boer, the U.N.'s top climate change negotiator, spoke after Miss Rice and, without directly rebutting Miss Rice's points, sounded a different tone.

"We have been shown that the economic costs of delayed and pragmatic action will by far exceed the economic costs of taking early, strong and assertive action," Mr. de Boer said.

Mr. de Boer's comment reflects the general European attitude, which has been adopted by many in the Democratic Party in the U.S., that the threat of global warming is imminent and requires steps such as mandatory caps in emissions.

The Bush administration is less certain of the scope of the global warming threat, and believes caps or other such goals should be set by each country for themselves.

"Though united by common goals and collective responsibilities, all nations should tackle climate change in the ways that they deem best," Miss Rice said.

Critics have questioned whether this U.S. conference is a distraction from the U.N. process, which next picks up at a December meeting in Bali, Indonesia.

The goal is an agreement by the end of 2009 on a global approach to curbing emissions after the Kyoto protocol expires at the end of 2012.

-- Jon Ward, White House correspondent, The Washington Times