Delegates have approved a framework for setting national pledges to be submitted to a summit next year.
Differences over the draft text caused the talks in Lima, Peru, to overrun by two days.
Environmental groups have criticised the deal as a weak and ineffectual compromise, saying it weakens international climate rules.
The talks proved difficult because of divisions between rich and poor countries over how to spread the burden of pledges to cut carbon emissions.
'Not perfect'
The BBC's Matt McGrath in Lima says none of the 194 countries attending the talks walked away with everything they wanted, but everybody got something.
There was a great sense of relief among delegates when the announcement came in the early hours of Sunday morning, he adds, following 48 hours of talks without a break.
Peru's environment minister, Manuel Pulgar-Vidal, who chaired the summit, told reporters: "As a text it's not perfect, but it includes the positions of the parties."
The agreement was adopted hours after a previous draft was rejected by developing countries, who accused rich nations of shirking their responsibilities to fight global warming and pay for its impacts.
The final draft is said to have alleviated those concerns with by saying countries have "common but differentiated responsibilities".We've got what we wanted," Indian environment minister Prakash Javedekar told reporters, saying the document preserved the notion that richer nations had to lead the way in making cuts in emissions.
It also restored a promise to poorer countries that a "loss and damage" scheme would be established to help them cope with the financial implications of rising temperatures.
However, it weakened language on national pledges, saying countries "may" instead of "shall" include quantifiable information showing how they intend to meet their emissions targets.
The agreed document calls for:
An "ambitious agreement" in 2015 that reflects "differentiated responsibilities and respective capabilities" of each nation
Developed countries to provide financial support to "vulnerable" developing nations
National pledges to be submitted by the first quarter of 2015 by those states "ready to do so"
Countries to set targets that go beyond their "current undertaking"
The UN climate change body to report back on the national pledges in November 2015
Environmental groups were scathing in their response to the document, saying the proposals were nowhere need drastic enough.
Sam Smith, chief of climate policy for the environmental group WWF, said: "The text went from weak to weaker to weakest and it's very weak indeed."
Jagoda Munic, chairperson of Friends of the Earth International, said fears the talks would fail to deliver "a fair and ambitious outcome" had been proven "tragically accurate".
The talks followed last month's agreement on emissions targets between the US and China, but hopes it would encourage wider global agreement faded once talks began in Lima on 1 December.
On Saturday, US climate envoy Todd Stern had warned that the deadlock in the negotiations threatened the chances of a new global deal next year, saying it would be seen as "a major breakdown".
