Efforts to convince rich nations to toughen emissions cuts have failed to make much headway at climate talks in the Thai capital, the U.N. said on Friday.

Delegates from about 180 nations are meeting in Bangkok to try to narrow differences on ways to broaden and deepen the fight against climate change.

The September 28-October 9 talks are the last major negotiating session before environment ministers meet in Copenhagen to try to seal a tougher global pact to replace the Kyoto Protocol.

Progress toward high industrialized world emissions cuts remains disappointing during these talks. We're not seeing real advances there, Yvo de Boer, the head of the U.N. Climate Change Secretariat, told reporters.

Movement on the ways and means and institutions to raise, manage and deploy financing support for the developing world climate action also remains slow.

The U.N. climate panel says rich nations should cut emissions between 25-40 percent from 1990 levels by 2020 to avoid dangerous climate change. But the aggregate cuts pledged by industrialized states remains well below this level.

Many developing nations say rich countries should commit to 40 percent cuts by 2020, blaming them for most of the planet-warming greenhouse gases pumped into the atmosphere from burning fossil fuels over the past two centuries.

Poorer nations also demand cash and clean-energy technology to help them curb the growth of their own emissions.

CLEARER PICTURE

Negotiators in Bangkok are trying to trim a complex 180-page main draft text that will form the basis of the new climate pact from 2013. The U.N. hopes Bangkok will lead to a clearer picture of what a Copenhagen agreement might look like.

Scientists say a tougher deal is crucial to avoid the worst of more intense droughts, floods, melting glaciers and rising seas.

The Copenhagen agreement could also give a major push to greening the global economy, boosting investment in renewable energy, expansion of carbon markets and more efficient transport.

De Boer said the United States was a key reason why rich nations' 2020 emissions targets have not been finalized.

The United States never ratified Kyoto and is not among the 37 industrialized nations committed to emissions targets during Kyoto's 2008-12 first commitment period. Washington remains outside formal discussions on tougher post-2012 commitments.

Not knowing what the United States is going to be able to bring to Copenhagen really makes it very difficult for other countries in that Kyoto discussion to increase the level of ambition of their numbers, he said.

John Ashe, a senior diplomat who chairs a key U.N. group negotiating expanded Kyoto commitments, told Reuters in an interview it was unlikely pledged cuts by rich nations would change in Bangkok.

He also said developing nations had not changed any of their demands for tough cuts by rich countries.

He said it was still unclear what limits would be agreed on carbon offsetting by rich nations, such as investing in forest preservation projects in the developing world.

There will be a cap on offsets. There must be a cap.

No one is contemplating a situation where targets are met through just pure offsets, he said.

(Editing by Sanjeev Miglani)

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