UN Secretary General Ban Ki-moon has welcomed a US-backed climate deal in Copenhagen as an "essential beginning".
But he said the accord , reached with key nations including China and Brazil, must be made legally binding next year.
After intense wrangling, delegates passed a motion simply taking note of the deal, without formally adopting it.
The pact did not win unanimous support, amid outrage from some developing nations who said it lacked specific targets for reducing carbon emissions.
The accord includes a recognition to limit temperature rises to less than 2C and promises to deliver $30bn (£18.5bn) of aid for developing nations over the next three years.
It outlines a goal of providing $100bn a year by 2020 to help poor countries cope with the impacts of climate change.
The agreement also includes a method for verifying industrialised nations' reduction of emissions. The US had insisted that China dropped its resistance to this measure.
But the BBC's environment correspondent Richard Black says the Copenhagen Accord looks unlikely to contain temperature rises to within the 2C (3.6F) threshold that UN scientists say is needed to avert serious climate change.
US President Barack Obama described negotiations as "extremely difficult and complex", but said they had laid "the foundation for international action in the years to come".
"This progress did not come easily, and we know that progress on this particular aspect of climate change negotiations is not enough," he added.
Several South American countries, such as Nicaragua and Venezuela, were among a group saying the agreement had not been reached through proper process.
After an all-night negotiating marathon, the 193-nation two-week conference ended at 1426 GMT on Saturday.
"The conference decides to take note of the Copenhagen Accord of December 18, 2009," the chairman of the plenary session of the UN Framework Convention on Climate Change (UNFCCC) declared earlier in the day, swiftly banging down his gavel.
Environmental campaigners and aid agencies branded the deal toothless and a failure.
Robert Bailey, of Oxfam International , said: "It is too late to save the summit, but it's not too late to save the planet and its people."
Mr Ban told journalists: "It may not be everything we hoped for, but this decision of the Conference of Parties is an essential beginning."
The Copenhagen Accord is based on a proposal tabled on Friday by a US-led group of five nations - including China, India, Brazil and South Africa.
The UK's Climate Change Secretary Ed Miliband said it was very important that the adoption of the accord would allow the flow of money to begin.
But, he said: "We recognise there could have been more ambition in parts of this agreement. Therefore we have got to drive forward as hard as we can towards both a legally binding treaty and that ambition."
Delegates had battled through the night to prevent the talks ending without clinching an agreement.
The deal was lambasted by some developing nations when it was put to a full session of the UNFCCC.
The main opposition came from the ALBA bloc of Latin American countries to which Nicaragua and Venezuela belong, along with Cuba, Ecuador and Bolivia.
Venezuelan delegate Claudia Salerno Caldera said the deal was a "coup d'etat against the authority of the United Nations".
Lumumba Stanislaus Di-Aping, the Sudanese negotiator, said the accord spelled "incineration" for Africa and compared it to the Nazis sending "6 million people into furnaces" in the Holocaust.
But the African Union backed the deal and his statement was denounced by other delegations.
In a further twist, says BBC environment reporter Matt McGrath, there is to be a list of those countries in favour and against on the front of the final document, with some experts suggesting money will only flow to those who say yes.
During the summit, small island nations and vulnerable coastal countries had demanded a binding deal to limit emissions to a level preventing temperatures rises above 1.5C (2.7F) over pre-industrial levels.