Bush repeated his objections to the Kyoto treaty on climate change and suggested development of new technologies to cut down on heat-trapping greenhouse gases.

"There's no doubt in my mind we'll be driving a different type of automobile within a reasonable period of time -- one powered by hydrogen," he said during a stop in Denmark on the way to a G-8 summit in Scotland.

Bush said he would share strategies for developing alternatives to fossil fuels with G-8 leaders.

At the summit, British Prime Minister Tony Blair is hoping to achieve commitments to reduce emissions of the gases blamed for global warming. The United States is the only G-8 country that has not ratified the Kyoto Protocol on climate change, which calls for cuts in greenhouse gas emissions.

Bush said he was going to the Scotland summit to talk about "the post-Kyoto era."

"Kyoto didn't work for the United States, and it frankly didn't work for the world," Bush said at a joint news conference with Danish Prime Minister Anders Fogh Rasmussen. Bush said the treaty would have "wrecked" the U.S. economy, and noted it did not include developing countries.

However, Bush acknowledged that global warming was a problem and said "the U.S. needs to diversify from fossil fuels."

"I recognize that the surface of the Earth is warmer and that an increase in greenhouse gases is contributing to the problem," Bush said.