This story is part of CBC News special coverage of climate change issues in connection with the United Nations climate change conference (COP21) being held in Paris from Nov. 30 to Dec. 11.
What at the outset the French hosts called a "week of hope," is now coming to an end with frenetic, caffeine-fuelled all-nighters aimed at beating the clock.
The task is now nothing less than persuading many of the 196 countries represented here to give up on dearly held red lines to deliver a ground-breaking global deal on combating climate change after 20 years of trying.
Break-off negotiation groups, one initially chaired by French Foreign Minister Laurent Fabius himself, worked through the night and into the early morning to try to tackle some of the most divisive issues remaining in the 29-page draft.
Fabius, who still seems intent on announcing a final deal by 6 p.m. local time Friday, promised a new draft sometime this afternoon.
To speed things along, Fabius has also already recommended that legal and linguistic experts start reviewing "clean" sections over which there is no dispute.
But the remaining sticking points are significant, and from this point forward will likely require the direct involvement of, and concessions from, political leaders at home.
"Almost everything we need for an ambitious, equitable agreement is still in play," said Jennifer Morgan, director of the Climate and Energy Program at the U.S.-based World Resources Institute.
"We're still very much in flux."
Morgan said there are 10 to 15 issues that haven't yet been resolved.
They include questions such as:
- Whether a fund should be established to help compensate low-lying countries for loss and damage related to climate change.
- What temperature increase should be included as the maximum warming the world should reach: 1.5 or two degrees or somewhere in between.
- How to review and improve national goals for reducing emissions in the future.
"If we have really weak commitments on the table, we can't wait eight or 10 years before we revisit them," said Canadian Dale Marshall, national program manager of the group Environmental Defence.
"We have to revisit them in the short term."
At their core, they are all questions of ambition, money and transparency.
Many of the differences, however, actually revolve around a fundamental disagreement over the rights and obligations of developed versus developing countries in fighting climate change.
"Of course, these are the ones that have divided countries for years, so resolving them will still not be easy," said Duncan Marsh, director of international climate policy at the Nature Conservancy.
The overnight talks came following last night's marathon plenary session presided over by Fabius, in which several representatives expressed significant concerns about the latest draft in front of them.
For example, a bloc of developed countries that includes Canada felt the document wasn't "balanced," that it was tilted too far in favour of developing countries.
McKenna echoes concerns
"We are deeply disappointed at the weakening of several provisions," said Australia's Peter Woolcott, speaking on behalf of the so-called umbrella group.
In an interview with CBC News, Canadian Environment Minister Catherine McKenna echoed those concerns.
"So this idea where there might be some countries that, because they're feeling the effects of climate change, don't do their part, it just won't get us to the goal that we need to get to," she said Thursday.
"So that's something we really do want to see. We're also looking for countries to come back and improve on their targets. That's going to be important, so that we can make sure that we do reach an ambitious goal."
Several developing countries insisted that the mention of loss and damage was a red-line, existential issue. "We cannot leave Paris" without it, said the representative from Barbados.
By the end of the session, the exasperated look on the face of UN climate chief Christiana Figueres spoke loudly of the challenges still ahead, with only hours left before the deadline for an agreement.
Pay for consequences
Developed nations insist countries like India contribute more to help poorer countries reduce emissions and prepare themselves for the effects of climate change.
Wealthier but technically developing countries say the developed world brought on climate change during the industrial age and they should pay for the consequences.
Those countries, like India, have been watching closely for indications developed nations will compromise on that front.
Yesterday's announcement by U.S. Secretary of State John Kerry doubling the amount the U.S. is contributing (to $860 million US) was likely aimed at encouraging countries like India to step up and pitch in.
In a rapid-fire, urgent speech yesterday, Kerry urged the ministers assembled here to make compromises too.
"No matter how much half the world does to clean up its act, if similar steps aren't taken by the rest of the world, Earth still has a problem," he said.
"We have the rarest of opportunities to actually change the world, to improve the lives of millions of people. And in the next few hours, we need to work as never before not to let this opportunity slip by."
As the week slips by, there are some signs of the hope Fabius expressed earlier in the week.
A so-called "high ambition" coalition has formed that now includes the U.S., the EU and a number of developing countries trying to push in the same direction — and to break down the entrenched developed/developing fault lines.
In a sign of a possible basis for consensus, the grouping now has more than 100 members — including Canada, which was invited to join this week.
McKenna, who stayed up until 6:30 a.m. helping facilitate negotiations, has gradually been providing details publicly on Canada's position in the talks — a position that's been closely guarded until this week.
Canada supports a reference in the deal to the 1.5 degree figure as a goal for which to strive long term — while keeping two degrees as the official limit.
Need to be balanced
Like the U.S., Canada also opposes any mention of liability or compensation for vulnerable countries in the deal, saying it would open it up to the possibility of lawsuits.
"What would be very difficult is to have unlimited liability that future generations, future Canadians, would have to take on," she said in Thursday's interview.
In a statement Wednesday night, McKenna also said Canada was "deeply concerned" that the reference to human rights and the rights of indigenous people was still "under brackets" — meaning they're still being negotiated.
"We do consider that it is important to have the reference to these rights contained in a separate (preamble) paragraph that would be unbracketed as we move forward," she said.
Then, to Fabius, she added: "Like others, we reaffirm our support for you to guide us to a successful conclusion on Friday."