But a decision at marathon 193-nation talks merely took note of the new accord, a non-binding deal for combating global warming led by the United States, China, India, Brazil and South Africa.
The 193 nations stopped far from a full endorsement of the plan, which sets a target of limiting global warming to a maximum 2 degree Celsius rise over pre-industrial times and holds out the prospect of $100 billion in annual aid from 2020 for developing nations.
The plan does not specify greenhouse gas cuts needed to achieve the 2 Celsius goal that is seen as a threshold for dangerous changes such as more floods, droughts, mudslides, sandstorms and rising seas.
In a stormy overnight session, the talks came to the brink of collapse after Sudan, Nicaragua, Cuba, Venezuela and Bolivia lined up to denounce the U.S.-led plan after about 120 world leaders left after a summit on Friday.
U.N. talks are meant to be agreed by unanimity. Under a compromise to avoid collapse, the deal would list the countries that were in favor of the deal and those against.
The outcome may yield the initiative in forming world climate policy to the United States and China, the world's top two emitters of greenhouse gases, and underscored shortcomings in the chaotic U.N. process.
An all-night plenary session, chaired by Danish Prime Minister Lars Lokke Rasmussen, hit a low point when a Sudanese delegate said the plan in Africa would be like the Holocaust.
The document is a solution based on the same very values, in our opinion, that channeled six million people in Europe into furnaces, said Sudan's Lumumba Stanislaus Di-aping.
The reference to the Holocaust is, in this context, absolutely despicable, said Anders Turesson, chief negotiator of Sweden.
Other nations including European Union states, Japan, a representative of the African Union and the Alliance of Small Island States (AOSIS) urged delegates to adopt the plan as a U.N. blueprint for action to combat climate change.
We have a real danger of (U.N. climate) talks going the same way as WTO (trade) talks and other multilateral talks, Maldives President Mohamed Nasheed said, urging delegates to back the plan to prevent the process dragging on for years.
Many nations said the deal fell far short of U.N. ambitions for Copenhagen, meant as a turning point to push the world economy toward renewable energies such as hydro, solar and wind power and away from fossil fuels.
Before leaving, Obama said the deal was a starting point.
This progress did not come easily and we know this progress alone is not enough, he said after talks with China's Premier Wen Jiabao and leaders of India, South Africa and Brazil.
We've come a long way but we have much further to go, he said of the deal.
The meeting has had a positive result, everyone should be happy, said Xie Zhenhua, head of China's climate delegation.
China had resisted international monitoring of its emissions curbs and the final wording took into account Chinese concerns, speaking of the need to protect sovereignty.
European nations were lukewarm to a deal that cut out some goals mentioned previously in draft texts, such as a target of halving world greenhouse gas emissions by 2050.
Many European nations want Obama to offer deeper U.S. cuts in greenhouse gas emissions by 2020. But Obama was unable to, partly because carbon capping legislation is stalled in the U.S. Senate. Washington backed a plan to raise $100 billion in aid for poor nations from 2020.
The deal sets an end-January 2010 deadline for all nations to submit plans for curbs on emissions to the United Nations. A separate text proposes an end-2010 deadline for reporting back on -- but dropped a plan to insist on a legally binding treaty.
(With reporting by Gerard Wynn, Anna Ringstrom, John Acher, Anna Ringstrom, Richard Cowan, David Fogarty, Pete Harrison, Emma Graham-Harrison and Alister Bull in Washington; Writing by Alister Doyle; editing by Dominic Evans)