WASHINGTON - The United States unveiled a plan to cut greenhouse gases by 2020 on Wednesday and said President Barack Obama will attend U.N. climate talks in Copenhagen next month -- before other world leaders show up.

Obama would go to the December 7-18 talks in Copenhagen on December 9, the eve of a ceremony in nearby Oslo to collect the Nobel Peace Prize, the White House said. He would not return, however, for the final days when most hard bargaining is likely.

Washington said it would promise in Copenhagen a cut in greenhouse gases of 17 percent below 2005 levels by 2020, a cut of about 3 percent below the benchmark year used in U.N. treaties.

The United States is the last major industrialised country to offer a target for cutting greenhouse gases in a U.N.-led drive to slow rising world temperatures that could bring more heatwaves, desertification, floods and raise sea levels.

The White House said it hoped Obama's attendance would give momentum to the Copenhagen talks.

U.N. climate chief Yvo de Boer told reporters in Germany: It's critical that President Obama attends the climate change summit in Copenhagen. If he can deliver on his election campaign statements that Copenhagen needs to be a success by coming to Copenhagen himself, that I think will be critical to a good outcome.

Danish Prime Minister Lars Lokke Rasmussen said: I am pleased the American president will visit Copenhagen. The strong commitment of the American president to the climate change issue is very valuable.

'RIGHT CITY, WRONG DATE'

Some green groups were disappointed that he would miss the climax when other leaders arrive. The right city, the wrong date, it seems that he's just not taking this issue seriously, said Kyle Ash, Greenpeace USA climate policy advisor.
More than 65 world leaders have confirmed they will attend the conference, which the Danish hosts hope will clinch a deal which lays the foundation for a treaty to be agreed in 2010.

Obama has made climate change a priority of his administration, but a bill to guide a U.S. negotiating position is bogged down in the U.S. Senate.

The U.S. House of Representatives passed a bill that sets a 17 percent reduction target for emissions by 2020 from 2005 levels. A Senate version aims for a 20 percent cut.

The European Union is pressing for more aggressive cuts and has pledged at least a 20 percent cut in its emissions compared to 1990 levels.

Many governments and analysts have blamed the U.S. failure to propose a carbon cutting target sooner for the delay in agreement on a full climate treaty.

In the last two years, we have wasted a lot of time on marginal issues, technical issues, we haven't focussed on the core questions in the negotiations, said Yu Qingtai, China's climate change ambassador on Wednesday.

Yu hinted that China would bow to a milder ambition for the summit in Copenhagen: We think that the actual content of whatever is achieved is more important than the title of the document that is produced.

China had previously said only that it was studying the Danish proposal to defer agreement on a full treaty until 2010.

The U.N.'s de Boer said the world was depending on U.S. leadership. The world is very much looking to the United States, he said.
New Zealand's revised emissions trading plan passed into law on Wednesday, while neighbouring Australia moved a step closer to ending a deadlock stalling its carbon-trade legislation ahead of a vote this week.