Copenhagen. Marathon UN climate talks went into overtime on Friday with world leaders deadlocked on a deal to tame global warming, despite pleas for an agreement from US President Barack Obama.

At the scheduled 6 p.m. close of a summit, the climax of 12 days of negotiations in Copenhagen, leaders were still thrashing through the text of a draft accord — deeply split over how to curb carbon emissions and muster the funds to combat climate change.

One version of the draft did contain a call to prevent a rise in global temperatures of more than 2 degrees Celsius compared with pre-industrial times. But that figure falls well short of the demands of island nations who, with their very existence threatened by rising seas, have called for a cap of 1.5 degrees Celsius.

“Whatever the outcome, it looks bad for us,” said a member of the delegation from the Maldives, an archipelago that fears being swallowed up by the Indian Ocean within decades.

The draft also outlined a package for poor countries most vulnerable to an overheating world, starting with $10 billion a year from through 2012, and climbing to $100 billion a year by 2020.

A spokesman for the UN Framework Convention on Climate Change, Eric Hall, confirmed that there was no immediate end in sight to the talks. “Things are going to go on a long time,” he said.

After teams of negotiators and then ministers failed to end the impasse, it was left to the leaders themselves to work out the exact wording of a three-page draft accord. Different versions of the document showed the leaders particularly split over whether to fix a firm date for finalizing a legally binding treaty in 2010, and a commitment to slashing global carbon emissions in half by 2050.

Obama, whose presence here was intended to provide the momentum to propel the deal over the finishing line, had pleaded for unity while acknowledging that any agreement would be less than perfect.

“No country would get everything that it wants,” he told the summit. “The question is whether we will move forward together, or split apart.”

UN chief Ban Ki-moon said leaders faced a defining moment in history — and urged them not to blow it. “The world is watching,” he said. “It will be your legacy for all time.”

Also in Copenhagen, Indonesian President Susilo Bambang Yudhoyono said he remained hopeful that a last-ditch effort would result in a suitable agreement. He outlined Indonesia’s stance, which included the position that developed nations should commit to deeper emissions cuts and guarantee financial assistance for the developing world.

Yudhoyono expressed the importance of forest management in reaching Indonesia’s goal of 26 percent reduction in emissions by 2020.

“From the 26 percent, at least 60 percent of the effort comes in how to manage the forests in a sustainable way, including ways to prevent forest fires and illegal logging.

Meanwhile, barely an hour before the scheduled close, the 27 EU nations held their own meeting on the sidelines to discuss the state of play.

“Things are tough, but we don’t want a mediocre agreement,” French President Nicolas Sarkozy told reporters.

Japanese Prime Minister Yukio Hatoyama, who has offered nearly $20 billion toward a global climate fund, said failure to reach agreement would be a “disgrace.”

AFP, Reuters