British Prime Minister Tony Blair says he hopes to bring the United States back into global warming talks.
Mr. Blair said Wednesday - the day the Kyoto pact took effect - that global warming could become a catastrophe and that getting the United States back into a dialogue is one solution.
President Bush pulled out of Kyoto in 2001, saying it would hurt the U.S. economy. He has called for new technology as one way to cut greenhouse gases.
Some European leaders have criticized the United States for pulling out of the Kyoto treaty. They say they expect Mr. Bush to address the matter when he visits Europe next week.
Some information for this report provided by AP, AFP and Reuters.