The head of the UN climate summit pressed nations Friday to strike a deal as talks resumed after a break, with only four days left for negotiators to iron out differences over the fate of fossil fuels.
While UN climate talks rarely finish on time, COP28 president Sultan Al Jaber has set the ambitious goal of wrapping up the conference in Dubai on schedule at 11 am (0700 GMT) on Tuesday.
With ministers now in town to carry a deal across the line, 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 with deep suspicion due to his position as the head of UAE national oil firm ADNOC, 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.
A handful of countries, including oil-rich Saudi Arabia and major crude consumer China, have resisted the inclusion of language on a phase-out of fossil fuels in the final text so far.
A draft deal was released on Tuesday but negotiators failed to produce another text on Wednesday before heading into the break.
Tuesday's document contains three options on fossil fuels.
The first calls for an "orderly and just" exit from hydrocarbons, and the second that countries must accelerate efforts towards the phase-out of "unabated" fossil fuels -- those whose emissions cannot be captured -- and "rapidly" reduce their use to achieve net-zero CO2 in energy systems by around 2050.
US climate envoy John Kerry repeated on Wednesday that carbon capture technology was key to efforts to phase out fossil fuels -- a hint that Washington might be leaning towards the second option.
The third and most controversial option effectively proposes not addressing the issue at all.
A negotiator from the pro-phase-out camp said a "coalition is there" for a fossil fuel exit, but that the two opposing camps had yet to go head-to-head in talks.
Scientists warn that greenhouse gas emissions -- the bulk of which come from burning fossil fuels -- must fall by 43 percent by 2030 from 2019 levels for the world to reach the goal of limiting warming to 1.5 degrees Celsius.
Saudi Arabia has been the most vocal nation against a phase-out or even a phase-down of fossil fuels.
"As one of the largest producers of hydrocarbons, they refuse to have a solution imposed upon them," Umar Karim, an expert on Saudi politics at the University of Birmingham, told AFP.
Kristian Ulrichsen, a Middle East fellow at Rice University, said Saudi Arabia would seek a coalition with like-minded countries on fossil fuels, including China and Russia.
"The Saudis will not want to be cast as the sole holdout in favour of fossil fuel," Ulrichsen said.
Another thorny issue -- over who will host next year's COP29 -- appears to be headed towards an agreement after Armenia said it was dropping its rival bid in a goodwill gesture to try to normalise relations with its neighbour, petro-state Azerbaijan.
Next year is the turn of Eastern Europe and Russia. Under Western pressure over its invasion of Ukraine, Moscow has blocked the Bulgarian bid, saying no European Union member should take charge.
