SYDNEY, Australia – President Bush urged Pacific Rim nations today to band together on tackling global warming, saying all major polluters must be part of any solution. But finding consensus on the issue among Asian leaders at their annual summit has proven elusive.

Mr. Bush backed an Australian proposal that Asia-Pacific countries endorse a new, inclusive approach to the divisive challenge of climate change — one that unlike the current Kyoto Protocol would require firmer action by China and other developing countries.

“For there to be an effective climate change policy, China needs to be at the table,” Mr. Bush said at a joint news conference with Australian Prime Minister Howard. Messrs. Bush and Howard issued a joint statement that supported nuclear energy, new technologies and lots of dialogue to find a way forward on global warming.

The climate change issue is at the top of the agenda for Messrs. Bush, Howard and the leaders of 19 other Asia-Pacific economies gathering for an annual summit, held this year in Sydney’s famed Opera House, far behind a security cordon police set up to ward off trouble.

About 300 protesters, many of them high school students on a walkout to protest against Mr. Bush, the Iraq war and Mr. Howard’s support for both, staged an uneventful demonstration despite police threats of arrests for truancy.

Finding consensus on climate change among a diverse group that includes rich and poor countries has bedeviled senior officials from the Asia Pacific Economic Cooperation forum, who tried for a second day Wednesday to draft a statement the leaders would accept.

APEC’s developing countries, in particular, were trying to squelch the inclusion of specific targets to reduce emissions of the greenhouse gases that cause global warming, officials said.

Indonesia dislikes Australia’s call for emissions reductions because it wound undermine the U.N.-sponsored Kyoto accord and an upcoming successor conference in Bali, said an Indonesian official involved in the talks, who requested anonymity because he was not authorized to speak to the media.

The divide between developed and developing countries has troubled all climate change talks. The 1997 Kyoto Protocol sidestepped the problem by exempting developing nations from the emissions goals it set for industrialized countries. The exemption in part undermined the agreement, causing the U.S. and Australia to reject it as unfair.

Supporters of the Australian proposal on climate change said it was not meant to supplant U.N. efforts to forge a successor to Kyoto, which expires in 2012, but to influence the discussion.

An APEC endorsement could carry much weight since the grouping includes the four biggest emitters of greenhouse gases — the United States, China, Russia and Japan.

“All emitters must participate” in a new agreement, said Japanese Foreign Ministry spokesman Mitsuo Sakaba, whose government was backing the Australian proposal. “We should express political will at least.”

With Russia already agreeing to Kyoto caps, and Japan and America in favor of a new approach, pressure was growing on China, whose President Hu was set to hold separate talks with Messrs. Howard and Bush tomorrow.

Developing nations need to move beyond their view that stopping global warming should chiefly fall to wealthier countries and realize that the problem is a common challenge, Australian Foreign Minister Alexander Downer said.

“That is actually a very, very big challenge. There are a lot of developing countries, be they in APEC or outside of APEC, that are going to be resistant to that,” Downer told reporters. He later added: “This is tough diplomacy, but we’re working at it.”