With three days left in their marathon negotiating sessions and 940 decisions still to be made, envoys at the United Nations climate summit are advancing toward a deal that would limit fossil fuel pollution everywhere.

The talks that began Nov. 30 in Paris have drawn a record 150 world leaders and celebrities from Alec Baldwin to Arnold Schwarzenegger in support of the biggest agreement on global warming since 1997.

French Foreign Minister Laurent Fabius, who is hosting the discussions, is due to release Wednesday a new draft of the deal that aims to narrow the items still in dispute. The biggest stumbling block may be how to differentiate between the actions of developed and developing nations. While friction remains over everything from a $100 billion aid package to when pledges to rein in emissions will be reviewed, even the countries with the biggest demands say they’re working in a spirit of compromise.

“We have only green lines – we don’t recognize red lines,” India’s Environment Minister Prakash Javadekar told reporters in Paris on Tuesday.

Copenhagen

Delegates from the 195 countries at the conference are keen to underscore how different this gathering is from the last time they tried to reach a global deal on climate in 2009. Those talks in Copenhagen dissolved in finger-pointing between industrial and developing nations on who should move first on the problem.

“Everyone has learned the lesson of Copenhagen,” said Claudia Salerno, the envoy from Venezuela who was one of the people who blocked a deal in 2009. “We have never seen at this stage of the conference such a feeling of comfort and pleasantness.”

Still, she warned that “this is a very fragile process. We’re asking for France to look after this positive spirit which there is now – completely different to Copenhagen.”

Careful diplomacy by France’s envoys and rapprochement between the two largest emitters, the U.S. and China, have helped defuse many of the tensions that brought down Copenhagen. The deal is shaping up as one in which national targets on emissions won’t be binding internationally – an approach that’s drawing support from almost all nations instead of just the industrialized ones that were assigned limits under the 1997 Kyoto Protocol. So far, 185 nations have submitted pledges, with just ten missing.

‘Less Threatening’

“To a large degree the sting has been taken out of what is being negotiated,” Yvo de Boer, the UN diplomat who oversaw the summit in the Danish capital, said in an interview before the Paris talks began. “It’s much less threatening than what people had in mind at the time of Copenhagen.”

The biggest differences are on issues like measuring and verifying emissions reductions, the ambition of actions taken before 2020, when the Paris deal would take effect, and how the rules should apply differently in the poorest nations.

“Differentiation is a key political issue that pervades the entire structure of the proposed agreement,” Singapore’s minister for foreign affairs, Vivian Balakrishnan, told delegates in a meeting late on Tuesday. “It is very clear that the fault lines remain.”

‘Loss and Damage’

Also delicate is the wording of the industrial world’s commitment to back a “loss and damage” mechanism that would pay for climate-related damages in developing nations.

In all, the 48-page text negotiators have been working with since Dec. 5 has 940 sets of square brackets indicating where language hasn’t been tied down. That’s down from 1,618 gaps before the meeting began.

“I shouldn’t worry too much about that,” Su Wei, a negotiator from China’s delegation, said in an interview. “We are trying very hard to resolve those issues, and I’m sure we’ll try to find a proper solution, if not by Wednesday then maybe by Friday.”

Running Overtime

These meetings almost always overrun after days of round-the-clock discussions. Kyoto finished two days late, with technicians setting up for another event as the final press conferences convened. Last year’s meeting in Peru finished 36 hours late.

Fabius has kept negotiators on schedule, setting deadlines and delivering texts on time, much to the surprise of delegates themselves. Last week, he appointed one of the fathers of Kyoto, the former UN climate chief from Malta, Michael Zammit Cutajar to help gauge the way forward. At the weekend, he named 14 ministers from around the world to work in pairs to forge compromise on thorny issues. Tuesday he said he’d asked Venezuela’s Salerno to work on the preamble to the agreement.

When Fabius spoke in Tuesday’s meeting, he was at pains to flag the timetable, with a new text due at 1 p.m. Wednesday local time.

“I hope that numerous square brackets will be removed,” he said. “Tomorrow the stage will be a very important one, but it will not yet be the final result.”