DOHA Wrangling over aid to the developing world and the failure of rich countries to set tougher goals for fighting global warming threatened to derail U.N. talks among 200 nations on the final day on Friday.
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, told Reuters of the efforts to prevent more droughts, floods, heat waves and rising sea levels.
"The fact is that the international policy response is fundamentally behind where the science says we are. If you look at the difference there is always going to be a lag. That is the frustration," she said.
World carbon dioxide emissions are set to rise 2.6 percent this year, and are more than 50 percent higher than in 1990. Recent growth has come mostly from emerging nations led by China and India.
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.
"I urge you and beg you that the next few hours are the last," conference chairman Abdullah bin-Hamad al Attiyah said, announcing a new meeting at 11 p.m. (2000 GMT) to take stock of a package deal he called the "Doha Climate Gateway".
The two-week meeting in the capital of OPEC member Qatar was expected to run overnight into Saturday.
In one step forward, nations agreed a draft timetable late on Friday for work in 2013-15 towards a new, global U.N. deal to fight climate change by 2015 that is due to enter into force by 2020.
China lost a bid to insert language that would have extended a past division of the world into developed nations with "commitments" to cut emissions and developing nations with less stringent "actions". Instead, all would take "enhanced action".
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 percent below 1990 levels during the years 2008 to 2012.
"There is deep disappointment" about the failure of developed nations to keep past promises, said Tony de Brum of the Marshall Islands, spokesman for the Alliance of Small Island States.
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 (33-ft) high metal sculpture of a spider in the heart of the huge conference center in Doha. They said the proposed deal was too weak to help.
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 allow Poland to keep surplus carbon credits from Kyoto in a new period beyond 2012, but other EU nations agreed not to buy 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 percent of world greenhouse gas emissions.
The United States never ratified Kyoto. Developing nations say Kyoto is a vital step towards the a new global U.N. deal.