Instead a plenary session of delegates from 193 nations officially "took note" of the accord. Countries will now choose whether to opt in to the accord or not.
United Nations Secretary-General Ban Ki-moon told exhausted delegates that the deal was just the "beginning" of a process to create a legally binding accord and that countries had taken a "significant step" to lowering emissions of greenhouse gases, which are warming the planet.
Many developing nations fought the agreement because it does not include binding emission targets for developed countries and does not go far enough to avoid the most severe consequences of global warming, including rising sea levels and more frequent extreme weather.
"This is what was expected, although maybe a little less than expected," said Adil Najam, a Boston University professor who is also an advisor to the Pakistan delegation here. "The 'moment' did not rise to the occasion but if you focus on the substance, some key progress has been made."
Others began weighing in shortly after the announcement.
"We have never been so close to having so many agree on so much. If anything was clear at the Copenhagen talks, it's that the world is waiting for the US to act. When it does, President Obama can knit together the historic breakthroughs obscured by the end of the Copenhagen meeting," said Fred Krupp, president of Environmental Defense Fund.
Many countries want the US Congress to pass emissions-reduction legislation before they are willing to sign on a pact with mandatory greenhouse gas targets. The House has passed such a bill, but the Senate has not.
The conference also drew to a close without approving a pact that would have paid developing nations to protect the world's tropical forests from deforestation -- a significant cause of greenhouse gas emissions because the destruction of trees releases the carbon stored in them and, if they are not replaced, means there are fewer trees to absorb carbon dioxide from the atmosphere.
The Reducing Emissions from Deforestation and Degradation pact, known as REDD, was intended to changed the financial incentives that now make it more valuable for countries to cut trees to make way for agriculture and development.
The agreement Obama reached yesterday with China, India, Brazil and South Africa set a goal of keeping the average worldwide temperature rise to 3.6 degrees Fahrenheit above pre-industrial levels, or roughly 2 degrees above current readings. But it contained no binding emissions targets and set no long-term goal for how much global emissions should be reduced by 2050.
The deal includes a pledge by rich countries to provide developing nations $10 billion a year between 2010 and 2012 and a goal of increasing that to $100 billion a year by 2020 to help the developing world adapt to climate change and shift to greener technologies.
It lacks, however, any deadline for when countries would reach a legally binding emissions-reduction treaty. It had been widely expected the two-week Copenhagen summit would produce a political agreement that would lead to a binding agreement by next November, when another climate conference is to be held in Mexico City.
COPENHAGEN -- After debate extended through the night and into the afternoon, the international climate talks finally ended just before 3:30 p.m. local time without formally approving the controversial pact President Obama and four other nations reached Friday night.