Global emissions of the main greenhouse gas carbon dioxide will jump more than 39 percent by 2030 without new policies and binding pacts to cut global warming pollution, the top U.S. energy forecast agency said on Wednesday.

Nearly 200 nations are set to meet late this year in Copenhagen to hash out a new agreement to control greenhouse gases as the Kyoto Protocol expires in 2012.

Uncertainty that a global climate change deal can be reached at Copenhagen in December has dented confidence in the global greenhouse gas emissions market, a survey released on Wednesday showed.

Washington defended its plans to cut its greenhouse gas emissions as among the most ambitious in the world Tuesday as major economies meeting in Paris rallied around a Mexican plan to raise cash to fight climate change.

Global negotiations late this year need not specify greenhouse gas cuts for the United States and other rich countries, as long as they set the right note for later talks, a Chinese climate policy official said on Tuesday.

The head of shipping and oil group A.P. Moller-Maersk called on Tuesday on governments to reach a global climate deal for the shipping industry when they meet on a new climate treaty in December.

International shipping was not included in the Kyoto Protocol, a replacement for which the world will try to thrash out in Copenhagen in seven months.

Plans for the world's most comprehensive carbon-trading scheme face defeat or parliamentary delay after Australia's opposition said on Tuesday it will try to postpone a vote on the laws this year.

China won praise for moves to cap its surging greenhouse gas emissions at a meeting of major economies on Tuesday, even as Germany criticised the lack of progress towards a new United Nations climate treaty.

"China is very active," French Environment Minister Jean-Louis Borloo told reporters on the second day of the two-day meeting of 17 major emitters.

Rising sea levels that could wipe whole nations off the map and displace scores of millions of people are being overlooked in global climate change talks, island countries said.

Major emitters are pushing for greenhouse gas emissions cuts that are too low to prevent devastating sea rises, representatives said at the World Ocean Conference in Indonesia