BARCELONA, Spain (Reuters) - The United States came under pressure on Monday to follow other rich countries and set a 2020 goal for cutting greenhouse gases to rescue chances for a climate deal due next month in Copenhagen.
The prospective Danish hosts ratcheted up pressure on the United States at a final preparatory meeting in Barcelona, saying it could not come "empty-handed" to Copenhagen.
Some African countries threatened to walk out of the Barcelona talks, saying rich countries had to deepen their emissions-cutting targets. The head of the U.N. Climate Change Secretariat said a U.S. number was essential.
"We need a clear target from the United States in Copenhagen," Yvo de Boer told a news conference. "That is an essential component of the puzzle."
President Barack Obama, speaking at the White House to reporters, held out hope for "an important deal" in Copenhagen. But he tempered that optimism, saying such a deal might not solve "every problem on this issue, but takes an important step forward, and lays the groundwork for further progress in the future."
The United States has not yet offered a firm target for reducing emissions by 2020. By contrast, the European Union has promised a cut of at least 20 percent below 1990 levels by 2020 and several other developed nations have set goals.
Democrats in the U.S. Senate said they would try to start pushing legislation through a key committee on Tuesday, ignoring a planned boycott by minority Republicans. That legislation calls for a 20 percent reduction in U.S. carbon dioxide emissions by industry, from 2005 levels.
Even if the Senate Environment and Public Works Committee signs off on the bill in coming weeks, there is no evidence any measure will be approved by the full Senate this year.
Delegates at the Barcelona talks that run to Friday said time was fast running out to break a deadlock over how to share curbs on emissions between rich and poor and ways to raise billions of dollars to help developing nations combat climate change.
The role of forests threatened to add another complication to the faltering talks.
Moscow "will insist that the ability of Russia's forests to absorb carbon dioxide be taken into account," Prime Minister Vladimir Putin said, speaking after talks in Moscow with Danish Prime Minister Lars Lokke Rasmussen.
Rasmussen told Reuters he hoped within weeks to have enough on the table to invite world leaders to the December conference.
Australia said its emissions fell last year, if the effect of forest fires was excluded.
Both Denmark and the European Union urged Obama to do more to unlock a deal at the December 7-18 talks.
Danish Climate and Energy Minister Connie Hedegaard said she found it "very hard to imagine" that Obama could collect the Nobel Peace Prize on December 10 "in Oslo, only a few hundred kilometers (miles) from Copenhagen, and at the same time has sent an empty-handed delegation to Copenhagen."
"We have seen a significant, real change in the American position ... but we still expect more," said Swedish Environment Minister Andreas Carlgren, whose country holds the rotating presidency of the European Union.
Washington said it was committed to a U.N. deal.
"The notion the United States is not making enough effort is not correct," said Jonathan Pershing, head of the U.S. delegation in Barcelona, pointing to a series of measures under Obama to promote clean energy and cut emissions.
"Our view is that it is extremely important to be a party to this (Copenhagen) deal," he said. The United States is the second biggest greenhouse gas emitter after China.
African nations called for tougher emissions curbs from the developed world, and Gambia, Ethiopia and Algeria spoke in favor of walking out of the U.N. talks, said Antonio Hill of Oxfam.
Outside the conference center, protesters lined up hundreds of ringing alarm clocks to show time was running out to reach a deal meant to slow rising temperatures and floods, heatwaves, wildfires and rising seas.
(Additional reporting by Richard Cowan in Washington)
Editing by Andrew Roche and Peter Cooney