Still reeling from the worst terrorist attacks in French history, Paris will host nearly 140 world leaders gathering next week to spearhead a climate pact tasked with keeping Earth liveable for humanity.

US President Barack Obama on Sunday urged others to follow his example and come to the French capital to show that "a handful of killers does not stop the world from doing vital business."

No heads of state or government backed out of the November 30 opening after jihadist assaults killed 130 people just over a week ago, French Foreign Minister Laurent Fabius said on Saturday.

"On the contrary, some who had not yet responded have said they will come exactly because we cannot give in to terrorism," he said.

Preoccupied by a recent spate of extremist attacks around the globe, world leaders will have their work cut out for them at the 12-day climate huddle.

The highly-anticipated conference is tasked with fixing a problem that threatens the very well-being of our species: global warming.

After six years of preparatory negotiations, the 195 nations gathering under the UN flag remain sharply divided on a raft of intertwined issues.

There are at least three battlegrounds where the talks could stumble. As always, the first is money.

- 'Not a legitimate concept' -

In Copenhagen in 2009 -- the last time countries sought to craft a universal climate pact and failed -- it was agreed that poorer nations vulnerable to global warming impacts would receive $100 billion (94 billion euros) per year from 2020.

The money is to help them give up fossil fuels, and to shore up defences against climate-driven food scarcity, heat waves and storm damage.

International climate finance has grown steadily, reaching $62 billion in 2014, according to an estimate commissioned by the UN.

But developing nations want assurances that the flow of money will be recession-proof, come from public sources, and be earmarked for boosting resilience.

India's environment and climate minister Prakash Javadekar told the Business Standard last week that "predictable, scalable and new finance" is a redline issue.

Along with many other developing countries, New Delhi's pledge to engineer a massive switch to renewable energy is conditional on such aid.

Some 50 nations -- home to a billion people -- federated in the Climate Vulnerable Forum, meanwhile, are also pushing for funds for "loss and damage" from climate change impacts that can no longer be avoided.

Rich nations are willing to discuss the issue, but have drawn a line in the sand.

"The notion of so-called compensation or liability... is not a legitimate concept in this context and we would certainly not accept it in the agreement," a US official told journalists in Paris ahead of the summit.

A second thorny issue is defining a long-term goal.

All nations have embraced the target of capping global warming at two degrees Celsius (3.6 degrees Fahrenheit) over pre-industrial levels. The world has already warmed 1 C.

Some 170 nations accounting for more than 90 percent of the world's greenhouse gas output have filed carbon-cutting plans ahead of the Paris meeting.

But these voluntary commitments are not enough to get the job done, and place Earth on a dangerous 3 C trajectory.

- 6,000 journalists -

There is no prospect of enhanced pledges right now.

"At this point, our goal will not change," China's climate negotiator, Xie Zhenhua, said last week. Other countries, including the United States, have said the same.

The challenge -- and the yardstick for success in Paris -- will be to agree on an action plan that eliminates the gap over time.

That could mean periodic reviews of national plans to ratchet up emissions reduction efforts.

But countries do not agree on how often reviews must be done, or an in-built obligation to ramp up carbon-cutting efforts.

A third sticking point is the agreement's legal status.

The United States has consistently said it will not inscribe its emissions reduction targets -- 26-28 percent from 2005 levels by 2025 -- in a legally-binding international treaty.

At the same time, host country France has said the outcome must have legal force.

There has been some progress since Copenhagen, based on growing scientific evidence of the threat we face, and renewable energy becoming cheaper.

"We have stronger convergence on the broad contours of an agreement than we ever saw ahead of the Copenhagen conference," said veteran climate analyst Elliot Diringer.

Still, finding middle ground will be tricky, and the planet will be watching.

Some 6,000 journalists have sought accreditation for the 12-day meeting, twice as many as can be accommodated.

Civil society groups, however, have been left out in the cold.

France, citing security fears, has cancelled mass rallies to press for urgent political action planned for November 29 and December 12 in Paris.