Delegates rest on Saturday after a 24-hour period of plenary sessions at the UN climate summit in Copenhagen. (Heribert Proepper/Associated Press)The UN climate conference in Copenhagen formally closed Saturday after two weeks of divisive negotiations, which produced an agreement that seeks to cut greenhouse-gas emissions while giving participating countries more time to work out the details.

The three-page document, referring to a "strong political will" to fight climate change, was struck in the final hours of the summit Friday night after talks between U.S. President Barack Obama and Chinese Premier Wen Jiabao.

The agreement recognizes that an increase in global temperature should be kept to two degrees Celsius — the threshold that UN scientists say is needed to avert serious climate change — but the deal is not legally binding and has no long-term global targets for emissions cuts.

The Copenhagen Accord, put forward by a U.S.-led group of five nations — including China, India, Brazil and South Africa — also promises to deliver $30 billion US in aid over the next three years to help developing nations reduce emissions.

Industrialized countries could channel $100 billion US a year to poorer nations by 2020, but the money is contingent upon them submitting to UN monitoring.

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

It requires industrial countries to list their individual targets and developing countries to list what actions they will take to cut global warming pollution by specific amounts. Obama called that an "unprecedented breakthrough."

Prime Minister Stephen Harper called the agreement "realistic" and said Canada was "very comfortable" with it.

"It is an excellent accord and is good for the environment, and it is good for Canada," Environment Minister Jim Prentice told CBC News on Saturday. "In terms of Canada, this agreement really achieves all of the negotiating objectives we set going over to Copenhagen."

Obama left Copenhagen before the final text was issued. Soon after he boarded a plane for the U.S., environmental groups denounced the failure of wealthy countries to announce their final 2020 targets for cutting emissions.

Several countries, including Bolivia, Cuba, Nicaragua, Venezuela and Sudan, called the document unacceptable and said it had not been reached through a proper process.

UN chief calls agreement an 'essential beginning'

Although the agreement was not formally approved, the conference president said that delegates at a late-night plenary session — which extended the 12-day summit past its scheduled ending by four hours — agreed to "take note" of the document, or recognize that it exists.

Ban Ki-moon, the secretary general of the United Nations, welcomed the climate deal as an "essential beginning," but said it must be transformed into a legally binding treaty next year.

Kim Carstensen, director of the World Wildlife Fund's global climate initiative, said the deal has a number of shortcomings.

"I would have liked to see a clarity that we're moving toward a legally binding outcome. I would have liked to see a mandate and a timeline for when we're going to get it," he said. "How do we help the poorest countries adapt to climate change? We didn't get the details."

Kumi Naidoo, international executive director of Greenpeace, said world leaders have shown they're not taking the threat of global warming seriously.

"What we have here is not a fair, not a binding and not an ambitious outcome," he said. "For two years, since Bali, we have been working to actually urge our leaders to agree on the kind of set of agreements that will prevent catastrophic climate change. And sadly our leaders have not acted with the urgency that the situation calls for."