COPENHAGEN (AFP/Reuters) - Marathon UN climate talks lurched into overtime 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 6:00pm (1700 GMT) 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. A new draft for a climate deal in Copenhagen has dropped a reference to an end-2010 deadline for reaching a legally binding treaty that had been in a previous text on Friday. The new draft, obtained by Reuters, also introduced a name for the proposed agreement - the Copenhagen Accord. About 120 world leaders are meeting in the Danish capital seeking to unblock disputes over the text. The text stuck to a goal of limiting world temperature rises to a maximum rise of 2 Celsius above pre-industrial times to avert the worst effect of global warming. The blame game was already underway, with some of the leaders venting their frustration at the summits chairman Denmark, while leaders of small island states most at risk from rising sea levels expressed despair at events. The haggling capped two years of deadlock over crafting a new UN treaty from 2013 that would reduce global warming from mortal threat to manageable peril. 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 finalising a legally-binding treaty in 2010, and a commitment to slashing global carbon emissions in half by 2050. Scientists say failure to curb the rise in Earths temperature will inevitably lead to worsening drought, floods, storms and rising sea levels. Obama, whose presence here was intended to provide the momentum to propel the deal over the finishing line, had pleaded for unity while acknowledging 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 ... It will be your legacy for all time, said Ban. Obama held nearly an hour of talks with Chinese Premier Wen Jiabao and lined up a second session for the evening in a bid to narrow the divide between the worlds two biggest emitters of Earth-warming greenhouse gasses. China, having said it will implement voluntary emission cuts, is resisting calls for international scrutiny for fear it would infringe on its sovereignty. Russian President Dmitry Medvedev said the world community had clearly underestimated the task of reaching even a general declaration. One of his advisors said frustration boiled over in a meeting of around two dozen heads of state, many exhausted after working through the night. 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 dont want a mediocre agreement, French President Nicolas Sarkozy told reporters. Japanese Prime Minister Yukio Hatoyama, who has offered nearly 20 billion dollars towards a global climate fund, said failure to reach agreement would be a disgrace. Each draft did contain a call to prevent a rise in global temperatures of more than 2.0 degrees Celsius (3.6 degrees Fahrenheit) compared with pre-industrial times. But that figure falls way short of the demands of threatened island nations who, with their very existence threatened by rising seas, have called for a cap of 1.5 C (2.7 Fahrenheit). Whatever the outcome, it looks bad for us, said a member of the Maldives delegation, an archipelago which fears being swallowed up by the Indian Ocean in a matter of decades. The draft also outlines a package for poor countries most vulnerable to the ravages of an overheating world, kicking off with $10b a year from 2010 to 2012, and climbing to $100b by 2020.