Copenhagen ? Two years of laborious negotiations on a climate agreement ended Friday with a political deal brokered by President Barack Obama with China and other emerging powers but denounced by poor countries because it was nonbinding and set no overall target for curbing greenhouse gas emissions.

German Chancellor Angela Merkel, a leading proponent of strong action to confront global warming, gave the Copenhagen Accord grudging acceptance but said she had “mixed feelings” about the outcome and called it only a first step.

Obama’s day of frenetic diplomacy produced a three-page document promising $30 billion in emergency aid in the next three years and a goal of channeling $100 billion a year by 2020 to developing countries with no guarantees.

The five-nation agreement includes a method for verifying reductions of heat-trapping gases — a key demand by Washington, because China has resisted international efforts to monitor its actions.

The agreement, which also includes India, South Africa and Brazil, requires industrial countries to list their individual targets and developing countries to list the actions they will take to cut global warming pollution by specific amounts. Obama called that an “unprecedented breakthrough.”

“We have come a long way, but we have much further to go,” he said.

If the countries had waited to reach a full, binding agreement, “then we wouldn’t make any progress,” Obama said. In that case, he said, “there might be such frustration and cynicism that rather than taking one step forward, we ended up taking two steps back.”

A final plenary session began debating the agreement early this morning with the aim of reaching enough consensus that the president of the conference, Danish Prime Minister Lars Loekke Rasmussen, could declare the document approved. But that outcome was thrown into question as a string of developing nations began to protest what they called an inadequate and nonbinding text.

The delegate from the Pacific island nation of Tuvalu — which is threatened by rising seas — told the meeting that his country’s future was not for sale. Cuba, Bolivia and Venezuela complained that they had no input into the drafting of the document.

Obama met twice with Chinese Premier Wen Jiabao in hopes of sweeping aside some of the disputes that had blocked progress. The U.S. and China are the world’s two largest carbon polluters.

The emerging outcome was a disappointment to those who had anticipated the Copenhagen Accord would be turned into a legally binding treaty. Instead, it envisions another year of negotiations and leaves myriad details yet to be decided.

European Commission President Jose Manuel Barroso said the deal was “clearly below” the European Union’s goal.

But British Prime Minister Gordon Brown said the agreement had almost universal support. “Let’s remember, a year ago nobody thought this sort of agreement was possible,” he said.