WRAPUP 1-UN climate treaty may need extra year

* December deadline too short for deal

* U.S. Senate committee approves carbon-capping bill

BARCELONA/WASHINGTON, Nov 5, Reuters - 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 Nov. 2 to 6 meeting of 175 nations in Spain, the last session before an accord is due in Copenhagen next month, has turned gloomy about prospects for salvaging a legally binding text in Denmark, delegates said.

Many world leaders have been saying in recent days that Copenhagen may agree a "politically binding" deal but that time is too short to agree a "legally binding" text. Delegates at the Barcelona talks discussed how long the delay may be.

"There is a lot of work still to be done," said Artur Runge-Metzger, head of the European Commission delegation, admitting that more time may be needed. Talks to agree on a U.N. pact began in Bali, Indonesia, in December 2007 with a two-year deadline.

Toughening the text to make it legally binding "should be done as early as possible...three months, six months," he told reporters.

John Ashe, chairman of talks to extend the existing Kyoto Protocol, said failing a December deal, which he preferred, negotiators should wrap up at the next meeting in Bonn around May, as happened in 2000. "We did it before, can do it again."

Some other delegates said it could take longer, partly because U.S. carbon-capping legislation will not be ready this year despite a vote by a Senate panel on Thursday in favour of a Democratic climate bill.

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.

A British official said it was likely to take "at least 6 months ... ideally no longer than a year" to agree details. After Copenhagen, the next meeting of environment ministers is in Mexico in December 2010.

STALLED

The Barcelona negotiations have stalled 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.

Swedish Prime Minister Fredrik Reinfeldt, whose country holds the EU's rotating presidency, said on a trip to India that a problem was that "some of the countries like the United States say 'we do not have the support in our Congress to make a ratification on an international agreement'."

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.

The bill will now become one of several initiatives aimed at attacking global warming. Senator John Kerry is leading an effort with some Republicans and the White House to craft a compromise bill, which likely would not be voted on by the full Senate until next year at the earliest.

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, agree actions by the poor to slow their rising emissions, ways to raise billions in funding and mechanisms to oversee funds.

Earlier, the head of the U.S. delegation in Barcelona, Jonathan Pershing, said China should roughly halve its greenhouse gas emissions by 2050 as part of a strong assault on global warming.