“All of us agreed that it is imperative for us to redouble our efforts in the weeks between now and the Copenhagen meeting to assure that we create a framework for progress in dealing with (a) potential ecological disaster,” Mr Obama said after talks with European Commission head Jose Manuel Barroso and Prime Minister Fredrik Reinfeldt of Sweden, who holds the EU presidency, and EU foreign policy chief Javier Solana.
Ms Merkel compared the battle against climate change to the struggle to bring down the Berlin Wall two decades ago this week.
She also backed Western calls for emerging nations to do more. “I’m convinced that once we in Europe and America show ourselves ready to adopt binding agreements, we will also be able to persuade China and India to join in,” she said.
But even as she and Mr Obama – praised by Mr Barroso for having “changed the climate on climate negotiations” – stressed the need for a more concerted effort to solidify a framework agreement at Copenhagen, US Republicans shunned a meeting on an Obama-backed bill to set the first US requirements on curbing carbon emissions blamed for global warming.
Asked what impact Ms Merkel’s speech might have on the US debate, Senator James Inhofe, the top Republican on the committee looking at the climate legislation, said: “None whatsoever.”
Democrat Ben Nelson was similarly blunt, answering the same question with a simple “no”.
Earlier, Mr Barroso said he was “worried by the lack of progress in negotiations” ahead of the December 7-18 climate meeting, and acknowledged a binding pact would not be ready by then.
The summit in the Danish capital has been set up to seal a treaty to succeed the landmark Kyoto Protocol, whose obligations to cut carbon emissions expire in 2012.
“Of course we are not going to have a full-fledged binding treaty, Kyoto-type, by Copenhagen,” Mr Barroso said. “This is obvious. There is no time for that.”
Mr Barroso said a meeting next year in Mexico could finalise a treaty but said Copenhagen needed to come up with the framework of the deal, and that the world’s largest economy in particular should take a lead role.
“What we are asking is the United States to show leadership in this, such an important issue,” Mr Barroso said.
He warned against a protracted process of negotiations akin to the stalled Doha round of global trade liberalisation talks.
“I think it is important not to give up before, because if we start … now to speak about Plan B in Copenhagen we’ll probably end in Plan F for failure.”
“Let’s not do to Copenhagen what has been happening with trade in Doha, where systematically every year we are postponing.”
Sweden’s Mr Reinfeldt said the United States should at least agree on targets for cutting emissions and on financing for developing nations.
“I said that we need to have a clear commitment on targets and on financing coming from the United States,” Mr Reinfeldt said after talks with key senators.
“We can understand if it’s not possible to have everything in place exactly now. But we want a full agreement in Copenhagen and we are able to work through details in the months that come after Copenhagen,” he said.
He spoke as pre-summit negotiations were under way in Barcelona, Spain, where divisions again ran deep between key developed nations and emerging economies.
An EU summit last week agreed that developing nations will need 100 billion euros per year by 2020 to tackle climate change, but failed to nail down how much it would give.
The US role in Copenhagen is overshadowed by the debate in Congress.
The House of Representatives in June narrowly passed the plan to curb carbon emissions but the bill – already criticised by other developed nations as not ambitious enough – is bogged down in the Senate.
Some Republicans, like former president George W. Bush, resist action on climate change as too costly to the economy and demand further commitments by emerging nations.