Copenhagen - After two weeks of delays, grandstanding and frantic deal-making, the United Nations climate change talks concluded here early Saturday with a grudging agreement by the participants to "take note" of a pact shaped by five major nations.

The final, 12-paragraph accord was a statement of intention rather than a binding pledge for action. Many countries said it was a flawed but essential step forward.

Yet there are doubts that it will provide for enough change in global energy use and emissions to make much difference in the atmospheric concentrations of the greenhouse gases linked to global warming. Even President Obama, a principal force behind the final deal, said the agreement would take only a modest step toward healing the atmosphere.

Many of the delegates left in a sour mood because the accord lacked so many elements they had considered crucial, including firm targets for emission reductions and a deadline for concluding a binding treaty.

Participants also said the contentiousness of the talks might have irreparably damaged the U.N.-led process for patching together a binding treaty on heat-trapping emissions. Many said that process had become unworkable because it was impossible to forge consensus on who bears the blame for climate change, what a solution would cost and who should referee the results.

"The climate treaty process isn't going to die, but the real work of coordinating international efforts to reduce emissions will primarily occur elsewhere," said Michael Levi, who tracked the talks for the Council on Foreign Relations.

That elsewhere will likely be a group of roughly 30 countries responsible for 90 percent of global emissions. It was these nations that Obama rallied Friday behind a deal that provides financing for poor countries to adapt to climate change and sets up a system for major economies to monitor their emissions.

But even if countries live up to their commitments on emissions, scientists say, a stark gap remains between their combined pledges and what would be required to avert disruptive climate changes.

The chances of success hinge on whether Obama can fulfill his promises to reduce American emissions and raise tens of billions of dollars to help other countries deal with global warming. That in turn depends in large part on whether Congress enacts a bill that puts a price on carbon and devotes a substantial part of the proceeds to foreign aid. And that is no sure thing.