BARCELONA, Spain — With the U.S. Congress still unable to agree on climate legislation that would make major reductions in greenhouse gases, European officials said Thursday they have given up on reaching an agreement on a climate treaty in time for the 192-nation conference in Copenhagen, Denmark, next month.

Yvo de Boer, the United Nations supervisor for climate talks, said: "I don't think we can get a legally binding agreement by Copenhagen," said de Boer, executive secretary of the U.N. Framework Convention on Climate Change. "I think that we can get that within a year after Copenhagen."

European and U.N. officials will try to craft a political deal that would call for commitments from both wealthy and developing countries. Industrial countries would commit to firm targets for reducing emissions of heat-trapping carbon dioxide and allocating funds for poor countries, while developing countries would specify their plans for low-carbon growth.

The failure to reach accord on a treaty after two years of negotiations left developing countries despondent.

"We are completely dismayed by the shuffling of feet and sliding backward of the developed countries," said Raman Mehta, program manager in India for global anti-poverty agency ActionAid.

Developing countries insist an amended Kyoto Protocol be the central document of a new treaty. The United States wants nothing to do with the protocol.

De Boer has urged negotiators to consider a transition agreement that would be adopted by consensus among the 192 countries. The proposal would delay the politically explosive question of the format the final agreement will take.

"People are more and more talking about a framework ... that you clarify further in the following months," said Artur Runge-Metzger, chief delegate from the European Union Commission.

Despite the troubled passage of U.S. legislation, delegates at the U.N. talks in Spain had not given up hope the administration of President Barack Obama will bring specific pledges to the final round of negotiations in Copenhagen.

Success at Copenhagen "depends very much on President Obama himself, on ... whether he can put numbers on the table or not," Runge-Metzger said.

There was no sign that developing nations were backing away from their demands for next month's meeting — including that industrial nations pledge to reduce emissions by at least 40 percent of their 1990 levels by 2020. Scientists say at least a 25-40 percent reduction from those levels is required to avert climate catastrophe.