President George W. Bush begins the second day of a Washington conference on global warming today under pressure to accept binding limits on emissions of greenhouse gases.
Mr Bush called the meeting as a precursor to United Nations talks in Bali in December that will aim to launch a successor to the Kyoto Protocol, a treaty that set limits on industrial nations' emissions.
Environmentalists said the Washington conference had produced nothing new and was an attempt to circumvent UN efforts on climate change, a charge Secretary of State Condoleezza Rice denied.
"All eyes are now on President Bush's speech," said a spokesman for South African Environment Minister Marthinus van Schalkwyk. "We hope [he] will signal a stronger commitment by the US to a multilateral solution and their willingness to engage on internationally agreed and binding emission reduction targets."
German Environment Minister Sigmar Gabriel said the fact that Mr Bush was speaking showed the White House would not return to its previous scepticism about the seriousness of the issue.
"This is a big step. The more you have official discussions about climate change . . . the more difficult it is to go backwards," he said.
A White House spokeswoman said the president would talk about eliminating tariffs so poor countries could have better access to less-polluting energy sources. Mr Bush has long opposed such curbs.