The failure of rich countries to set tougher goals for fighting global warming threatened to torpedo U.N. talks on the final day.
The United Nations tried to dampen already modest expectations for the two-week meeting in Doha, which is seeking to extend the Kyoto Protocol - the U.N. plan that obliges about 35 developed nations to cut carbon emissions but expires at the end of this year.
"There never is going to be enough ambition," Christiana Figueres, head of the U.N. Climate Change Secretariat, said of the efforts to prevent more droughts, floods, heatwaves and rising sea levels.
"The fact is that the international policy response is fundamentally behind where the science says we are," she said.
"If you look at the difference there is always going to be a lag. That is the frustration."
Greenhouse gas emissions are set to rise 2.6 per cent this year, propelled mainly by emerging nations led by China and India that say they need to burn more fossil fuels to end poverty.
The United States, Europe and other developed nations, facing economic slowdown at home, have refused to set out a timetable for a tenfold rise in aid towards a promised $100 billion a year from 2020 to help developing nations curb emissions and cope with the effects of climate change.
"Finance has become a make-or-break issue here," said Celine Charveriat of aid group Oxfam.
"The finance text is not worth the paper it is written on."
Poor nations have also accused the rich of reluctance to extend the Kyoto Protocol, which requires signatories to cut emissions by an average of 5.2 per cent below 1990 levels during the years 2008 to 2012.
"What we're lacking here is ambition," said Claudia Salerno of Venezuela.
The two-week meeting in the capital of OPEC member Qatar was widely expected to run overnight into the weekend due to the wide disagreements.
A U.N. panel of climate scientists has said that world greenhouse gas emissions should peak by 2015 to avert the worst effects of climate change.
Draft texts in Doha merely said they should peak "as soon as possible".
"Reject the texts!" a group of demonstrators chanted under a 10 metre high metal sculpture of a spider in the heart of the huge conference centre in Doha.
They said the proposed deal was too weak to help the climate.
Figueres saw several points of contention.
"Finance is on its way, it's a big issue," she said.
"The details of the Kyoto Protocol are a big issue, as well as ambition across the board."
In one step forward, the European Commission said EU countries had resolved a long-standing dispute over surplus sovereign pollution permits that had hampered the Qatar talks.
The deal, trying to paper over a rift between most EU nations and Poland, would restrict use of surplus carbon credits from Kyoto in a new period beyond 2012, but not cancel them.
Kyoto has been weakened by the withdrawal of Russia, Japan and Canada, meaning its backers are down to a core EU-led group including Australia and Switzerland that account for less than 15 per cent of world greenhouse gas emissions.
The United States never ratified Kyoto.
Developing nations say Kyoto is a vital step towards a new global U.N. deal, meant to be agreed in 2015 and to enter into force from 2020.