An elusive universal pact to save mankind from disastrous global warming is within reach, the French host of UN talks said Wednesday as he released a new blueprint just 48 hours before the deadline for a deal.

Foreign Minister Laurent Fabius cautioned the toughest issues still needed to be resolved, as he appealed for compromise among the ministers and other negotiators from 195 nations gathered in the northern outskirts of Paris.

But, after releasing a streamlined draft of the accord that eliminated hundreds of smaller points of dispute, Fabius voiced confidence an accord could be signed by Friday to rein in greenhouse gases that warm the planet.

"I am convinced we can reach a deal but to do so we must unite our forces and set our compass on the need for compromise," Fabius told the delegates.

The UN talks have been billed as the last chance to avert the worst consequences of global warming: deadly drought, floods and storms, and rising seas that will engulf islands and densely populated coastlines.

More than two decades of international diplomacy have failed to produce such an accord, which would require a transformation of the world's energy system away from its reliance on highly polluting coal, oil and gas.

Deep divisions -- primarily between rich and poor nations -- over how to pay for the costly shift to renewable forms of energy, such as solar and wind, have bedevilled the UN climate process.

While the biggest arguments are yet to be resolved in Paris, negotiators and long-time observers agreed following the release of the draft that a deal could be reached.

"Our sense is that almost everything we need for an ambitious, equitable agreement is still in play," Jennifer Morgan, global director of the climate programme at the World Resources Institute, told reporters.

"But there is clearly an immense amount of work to be done in the coming hours."

- Good, bad and ugly -

However some campaigning groups said they were concerned that world powers, in their rush for an agreement, may settle for a weak accord that does not do enough to curb greenhouse gases.

"It's a mix of the good, the bad and the ugly, but we've got three days to force the worst stuff out and get a decent deal. It's crunch time now," said Kaisa Kosonen, a climate policy expert with Greenpeace.

Taking effect in 2020, the Paris agreement would seek to cut greenhouse gas emissions deeply enough to curb global warming to less than two degrees Celsius (3.6 degrees Fahrenheit) over pre-Industrial Revolution levels.

In a victory for dozens of nations most vulnerable to rising sea levels and fierce storms, a more ambitious cap of 1.5C was also kept as an option in the draft accord released on Wednesday.

"We have never been this close to a climate change agreement," Thoriq Ibrahim, Maldives Environment Minister and chair of the Alliance of Small Island States, said in response to the latest draft.

"It's now up to us ministers to show the leadership needed to make hard decisions that put the interests of people and the planet ahead of short-sighted politics."

- Deal-busters -

One of the biggest potential deal-busters remains money.

Rich countries promised six years ago in Copenhagen to muster $100 billion (92 billion euros) a year from 2020 to help developing nations make the costly shift to clean energy, and to cope with the impact of global warming.

But how the pledged funds will be raised still remains unclear -- and developing countries are pushing for a promise that the amount will be ramped up in future.

Meanwhile, rich nations are insisting that developing giants work harder to tackle their greenhouse gases, noting that much of the world's emissions come from their fast-growing economies.

Most nations submitted to the UN before Paris their voluntary plans to curb greenhouse gas emissions from 2020, which was widely hailed as an important platform for success.

But scientists say, that even if the cuts were fulfilled, they would still put Earth on track for warming of at least 2.7C.

One of the remaining battle fronts in Paris is a debate over when and how often to review those national plans, so that they could be "scaled up" with pledges for deeper emissions cuts.

Some developing nations insist they should not be pressured into deeper cuts, insisting that responsibility rests with rich nations that have burnt the most fossil fuels since the Industrial Revolution.

In a dramatic and timely example of the world's fate if rampant coal burning goes unchecked, choking smog has descended on the Chinese capital of Beijing and surrounding cities this week.

A red alert, ordering factories to close and recommending children stay at home, was raised in Beijing for the first time on Monday, followed by 27 other cities on Tuesday.

China is the world's biggest emitter of greenhouse gases, primarily because of its reliance on coal to provide cheap energy for its 1.3 billion people as they go through a remarkable economic transformation.