The two-day gathering, which starts on Wednesday in Honolulu, is meant to spur UN negotiations for an international climate agreement by 2009, so a pact will be ready when the current carbon-capping Kyoto Protocol expires in 2012.

The Bush administration rejects the Kyoto plan, saying it unfairly exempts developing countries from cutting back on emissions, and could cost US jobs. Instead, Washington favors voluntary measures and "aspirational goals" to limit climate change, aided by easier transfer of environmental technology.

In addition to the United States, by many counts the biggest emitter of climate-warming carbon dioxide, the conference is expecting representatives from Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Mexico, Russia, South Africa, South Korea and the United Kingdom.

The United Nations and the European Union will also be represented.

This is the second time this group has convened -- the first time was in Washington in last September -- and there has been some skepticism among environmentalists about the effectiveness of this process.

"The question back in September was, 'Does the fact that they're launching this process indicate some change in the position of this administration?"' said Angela Anderson of the non-partisan Pew Environment Group.

The answer, Anderson said in a telephone interview, is no: "There has been no change in position whatsoever in this White House. They were hoping to sell their position to the rest of the world and that's not working."

James Connaughton, the head of the White House Council on Environmental Quality, played down expectations for the Hawaii meeting.

"I think these will be iterative discussions, which the initial goal will be to lay out a variety of options without holding any country to a particular proposal," Connaughton told reporters at a briefing on Friday. "We're trying to do this in a collaborative way, rather than in the more classic 'You bring your number, I bring my number, and we start kicking them around."'

President George W. Bush drew criticism at the September meeting for his opposition to the mandatory limits on carbon emissions specified by the Kyoto agreement and supported by every other major industrialized country.

The criticism continued in December at a global climate meeting in Bali, Indonesia, where U.S. representatives -- including Connaughton -- were booed for opposing demands by poor nations for the rich to do more to help them fight climate change.

Back in Washington, the Democratic-controlled Congress last week grilled Connaughton and another top Bush administration official, Stephen Johnson, chief of the Environmental Protection Agency, over two hot-button issues: EPA's rejection of a push by California and 15 other states to set higher standards than the US government for vehicle emissions, and the administration's overall policy on climate change.

Another environmental case drawing unwelcome attention is the US government's delay in deciding whether polar bears should be classified as threatened by climate change as their icy habitat melts. The postponed deadline for issuing this decision is February 9 -- three days after an expected sale of oil and gas leases in the Chukchi Sea off the Alaskan coast, where thousands of polar bears live.

The Hawaii meeting begins two days after Bush's final State of the Union address. Connaughton declined to say whether Bush would discuss greenhouse emissions in this major speech, but said climate change was "among the items at the top of the agenda" in presidential discussions with world leaders.

"World leaders and the president are very, very engaged, and I think you'll see that continued engagement all the way through this year," Connaughton said. Bush leaves office on January 20, 2009.