Dubai - The head of UN climate talks pressed nations Friday to move fast to deliver an “unprecedented” pact on tackling global warming, as negotiators scrambled to bridge differences over phasing out fossil fuels. While UN climate talks rarely finish on time, COP28 president Sultan Al Jaber has set the ambitious goal of wrapping up the summit in Dubai on schedule at 11 am (0700 GMT) on Tuesday. With ministers now in town, Jaber said he wanted negotiators to produce a new draft deal on Friday. Despite disagreements over the future of fossil fuels, Jaber voiced optimism that the talks hosted by the oil-rich United Arab Emirates can finish with a historic agreement. “We have the potential to deliver a paradigm shift,” he said Friday after delegations from nearly 200 nations took a breather the day before. “Let us please get this job done. I need you to step up and I need you to come out of your comfort zones,” he said. Climate campaigners have viewed Jaber -- head of UAE national oil firm ADNOC -- with deep suspicion, but he has sought to assure sceptics by stating that a phase-down of fossil fuels was “inevitable”. COP28 kicked off last week with the landmark launch of a loss and damage fund for nations devastated by climate change. “We have surprised the doubters and inspired the optimists,” Jaber said, telling reporters later that he was “positive, hopeful and optimistic”. “I also feel a sense that something unprecedented is possible to happen here at COP28,” he said. A handful of countries, including oil giant Saudi Arabia and major crude consumer China, have resisted the inclusion of language on a phaseout of fossil fuels in the final text.