Climate deal must have immediate effect, says Obama

US president Barack Obama said on Tuesday next month's climate talks in Copenhagen should cut a deal with "immediate operational effect", even if its original aim of a legally binding pact is not achievable.

Obama was speaking after talks with Chinese President Hu Jintao in which he said the world's top two greenhouse gas emitters had agreed to take "significant" action to mitigate their output of carbon dioxide.

"Our aim (in Copenhagen) ... is not a partial accord or a political declaration but rather an accord that covers all of the issues in the negotiations and one that has immediate operational effect," Obama said.

Denmark, host of the December 7-18 climate talks, welcomed Obama's comments and said it expected the United States and all developed nations to promise firm emissions cuts and new cash to help the poor cope with global warming, even if no treaty text could be agreed.

Danish prime minister Lars Lokke Rasmussen won backing on Sunday from Obama and other leaders at an Asia-Pacific summit for his scaled-down plan for a politically binding deal, with a legally binding one delayed until 2010.

"The American president endorsed our approach, implying that all developed countries will need to bring strong reduction targets to the negotiating table in Copenhagen," he told about 40 environment ministers meeting in the Danish capital.

German chancellor Angela Merkel was also keen that the momentum for a deal should be maintained.

"We will make very clear that we continue to support ambitious goals for Copenhagen," she told reporters before a cabinet meeting.

"We must do everything to ensure that we move quickly to get a binding agreement. Even if this can't be reached in Copenhagen, it can't be pushed back forever."

Together the United States and China account for 40% of world emissions, so their support is vital to any accord, but Washington has been reluctant to promise firm emissions cuts by 2020 since carbon-capping legislation is stalled in the Senate.

Obama said Washington and Beijing had committed to cooperate in areas including renewable energy, cleaner coal and electric vehicles.

Hu said the two sides had committed to working more closely on global warming and called for a "positive outcome" from the talks in Denmark. He has refused to back a scaled-down political deal, which Beijing says it is only "studying".

Obama's call on Tuesday for a broad agreement taking effect immediately suggests he is keen to walk away from the climate summit with more than just a piece of paper. But the stalling of legislation hampers him.

US senator John Kerry, who is leading Senate negotiations on a compromise US measure, said he and other Democrats were working toward "trying to see if we can get this to the (Senate) floor sometime in the early spring, as early as possible".

The Senate bill would cut US emissions back to about 7% below 1990 levels by 2020. Developing nations led by China and India want developed nations to cut emissions by an average of at least 40% by 2020.

Some in China, and other developing nations, are suspicious that the push for a delay is a rich-nation ploy to defer facing costly responsibilities for decades of emissions.

Beijing has invested large amounts of diplomatic capital in reaching a climate deal. Hu this year unveiled China's first pledge to curb carbon emissions at a UN summit.