BARCELONA/WASHINGTON - A U.N. climate treaty may need an extra year beyond a December deadline to agree details, delegates at U.N. talks said on Thursday even as a U.S. Senate committee approved a carbon-capping bill.

The November 2-6 meeting of 175 nations in Spain, the last session before a U.N. accord is due in Copenhagen next month, turned gloomy about salvaging a strong deal after two years of negotiations.

World leaders have also said in recent days that Copenhagen may merely agree a politically binding deal rather than a full legally binding treaty. In Spain, negotiators suggested extensions from three months to a year or more.

Toughening a Copenhagen text if it fall short of a binding deal should be done as early as possible ... three months, six months, said Artur Runge-Metzger, head of the European Commission delegation.

A British official said it was likely to take at least six months and ideally no longer than a year to agree details. After Copenhagen, the next meeting of environment ministers is in Mexico in December 2010.

Talks to agree on a U.N. pact began in Bali, Indonesia, in December 2007 with a two-year deadline to agree a pact meant to fight a rise in temperatures, more floods, droughts or rising sea levels.

But recession has hit many nations and carbon-capping legislation in the United States, the biggest emitter after China, is unlikely to be ready this year despite a vote by a Senate panel on Thursday in favor of a Democratic climate bill.

John Ashe, chairman of talks to extend the existing Kyoto Protocol, said negotiators should wrap up at the next meeting of officials in Bonn around May if Copenhagen stalls, as happened when a previous U.N. meeting was suspended in 2000.

We did it before, we can do it again, he said.

And a Japanese official said unless it's agreed within six months after Copenhagen it will perhaps be the following year because of the U.S. mid-term elections. About a third of the U.S. Senate is up for re-election in November 2010.

BOGGED DOWN

The Barcelona negotiations have got bogged down with disputes between rich and poor including a day-long boycott by African nations who accuse the rich of failing to set themselves deep enough 2020 goals for curbing greenhouse gas emissions.

It seems that somewhere, someone decided 'let's shift gear, let's make sure we don't move so much', said Bruno Sekoli of Lesotho, chair of the group of least developed nations.

Still, he said a delay was better than a very bad deal.

In Washington, the U.S. Senate Environment and Public Works Committee approved a Democratic bill that would require industry to cut emissions of greenhouse gases by 20 percent by 2020 from 2005 levels.

I think this is a great signal for Copenhagen that there's a will to do what it takes to advance this issue, committee Chairman Barbara Boxer told reporters after her panel voted.

But Democrats are likely to fall far short of their goal of passing legislation in the full Senate before Copenhagen as Boxer's bill lacks enough support for full approval.

Yvo de Boer, head of the U.N. Climate Change Secretariat, has said Copenhagen should at least set 2020 greenhouse gas emissions goals for rich nations including the United States, agree actions by the poor to slow their rising emissions, ways to raise billions in funding and mechanisms to oversee funds.

Also in Barcelona, the World Bank announced $1.1 billion funding for clean energy and preparation for climate change in Africa, from a total pot of $6.3 billion pledged by donors in funds for developing nations.

China Mexico Climate change Climate