Developing and developed countries , including the US, Brazil, China, South Africa and India have opened what US officials describe as not sufficient to combat the threat of climate change but it's an important first step.
But the UN and other nations at the conference had yet to announce that they had also agreed to a deal. A Brazilian official said key countries took several important decisions but the UN negotiating process was still ongoing.
The agreement sets a target of two degrees Celsius for the increase in global temperatures. Countries are to provide details on how they would implement carbon reduction on a national level, and rich countries would provide financing and support to developing nations.
They were not able to agree a legally binding treaty, but emerged with a declaration of several key points.
Negotiators will continue to work through the weekend in order to make further progress.
Draft texts are emerging from a meeting of world leaders at the United Nations-sponsored conference on climate change, in a last-minute effort to hammer out a deal after two weeks of inconclusive talks by lower officials.
A draft agreement circulated Friday said cuts in greenhouse-gas emissions by 50 percent by 2050 from 1990 levels are required according to science to keep the earth temperature increase below two degrees Celsius.
But agreements on specifics eluded representatives of more than 190 nations at the summit.
Rich countries should commit to reduce their CO2 emissions by at least 80 percent by 2050, the draft states.
The draft also drops a previous 2010 deadline for achieving a legally binding treaty to fight global warming.