Washington - US President George W. Bush on Monday said it was time to move past a debate over whether human activity is a significant factor behind global warming and into a discussion of possible remedies. "I have said consistently that global warming is a serious problem. There's a debate over whether it's manmade or naturally caused," Bush told reporters.

"We ought to get beyond that debate and start implementing the technologies necessary to enable us to achieve a couple of big objectives: One, be good stewards of the environment; two, become less dependent on foreign sources of oil, for economic reasons as for national security reasons," he said.

Bush cited "clean-coal technology," efforts to develop automobiles powered by hydrogen or ethanol, and his push for the United States to develop significant new nuclear energy capabilities.

"The truth of the matter is, if this country wants to get rid of its greenhouse gases, we've got to have the nuclear power industry be vibrant and viable," he said.