WASHINGTON - U.S. President George W. Bush kicks off the second day of a conference on global warming on Friday under pressure from the world's major economies to accept binding limits on emissions of greenhouse gases.

Bush called the meeting as a precursor to United Nations talks in Bali in December, which will aim to launch a successor to the Kyoto Protocol, a treaty that set limits on industrial nations' emissions.

Environmentalists said the conference produced nothing new and was an attempt to circumvent U.N. efforts on climate change, a charge Secretary of State Condoleezza Rice denied.

Participants will watch Bush, who favors voluntary targets to curb emissions, for any shift in the U.S. position.

"All eyes are now on President Bush's speech," said South African Environment Minister Marthinus van Schalkwyk through an aide. "We hope (he) will signal a stronger commitment by the U.S. 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 Bush was speaking showed the White House would not return to its previous skepticism about the seriousness of the issue.

"This is a big step," he told reporters. "The more you have official discussions about climate change ... the more difficult it is to go backwards."

White House spokeswoman Dana Perino said the president would talk about eliminating tariffs so poor countries could have better access to less-polluting energy sources.

"He will talk about the need for new technologies in order to help solve this problem," she told a briefing.

Europeans say technology is crucial but not a substitute for binding targets on emissions. Bush has long opposed such curbs. He rejected Kyoto, saying it unfairly excluded fast-developing nations and would hurt the U.S. economy.

The Washington meeting, which followed a similar U.N. conference on Monday, drew participants from the EU, France, Germany, Italy, Britain, Japan, Canada, India, Brazil, South Korea, Mexico, Russia, Australia, Indonesia, and South Africa.

Delegates were gearing up for a possible confrontation about the meeting's written conclusions. Gabriel said Germany would not support them if they did not reflect the fact that most of the countries present wanted binding targets.