Climate diplomats wrapped up technical talks Thursday saying they were on the right track but still far from delivering on the promise of the historic pact forged in December.

Negotiators from 196 countries worked along three parallel tracks to put flesh on the bone of the Paris Agreement, the fruit of two decades of often contentious wrangling between wealthy and developing nations.

The accord -- which could enter into force later this year, far sooner than expected -- sets ambitious goals for capping global warming and funnelling trillions of dollars to poor countries facing an onslaught of climate damage.

The 10-day session in the German city of Bonn focused mainly on elaborating a "rule book" for implementation, and laying the groundwork for a high-level meeting in November in Marrakesh, Morocco.

"It has been a very constructive session," said Elina Bardram, top negotiator for the European Union, expressing a view echoed by other diplomats and observers.

"We are moving well beyond the disagreements that characterised the negotiations for so many years."

Christiana Figueres, the outgoing UN climate chief, also saw a "new willingness" to work collectively, but warned that time was running out.

"My concern is whether the transformation is going to happen fast enough to avert the worst impacts," she told AFP, referring to the global shift from fossil fuels to green energy.

"It is a race against the clock."

The most urgent question on the agenda remains how to ramp up national plans for slashing greenhouse gas emissions.

The Paris pact calls for capping global warming at well below two degrees Celsius (3.6 degrees Fahrenheit), and 1.5 C (2.7 F) if possible.

But voluntary national pledges to cut carbon pollution would still see Earth's surface heat up by three degrees Celsius (5.4 degrees Fahrenheit) compared to the pre-Industrial Era benchmark, a scenario scientists describe as catastrophic.

Much discussion in Bonn centred on how to plug this "emissions gap", and what efforts can be made before 2020, when these national carbon-cutting plans go into effect.

Barely 1 C of global warming so far has already fuelled a crescendo of devastating impacts.

Droughts in Africa and Asia are threatening food supplies, and rising seas could force millions to seeking higher ground.

- $100 billion promise -

2015 was by far the hottest year on record, and scientists predict that 2016 could be even worse.

In Bonn, developing countries pushed for hard numbers and a timetable for financial aid to make the switch from dirty to clean energy, to adapt to future climate change and to repair damage done.

"Adaptation has been short-changed," said Armelle Le Comte of Oxfam France.

"Developed countries must present a roadmap to show how they will deliver on their promise to deliver $100 billion (90 billion euros) a year" starting in 2020.

Morocco has billed the November high-level meeting they will host as the "action COP," or Conference of the Parties.

Mohamed Adow, senior climate advisory for Christian Aid, said the focus should be on the rapid transition to clean energy.

"Marrakesh needs to be seen as the Renewables COP," he said.

The unexpected speed with which the Paris deal is moving towards ratification shows strong political momentum, but creates other problems that will have to be sorted out, diplomats said.

The European Union -- which fought hard to set the Paris deadline for a deal -- could find itself in the awkward position of its member states not being among the ratifiers of the agreement when it goes into effect.

"If there is an early entry into force, we may not be part of that," said Ivo de Zwaan of the Netherlands, speaking for the EU.

Negotiators also grappled with issues including transparency in reporting of emissions reductions and financial transfers; how science should inform the negotiating process; and the best way for governments to interface with the business and financial sectors.

Climate change still a 'race against the clock': UN climate chief
Bonn (AFP) May 26, 2016 - Even after the world sealed a historic climate deal in Paris, the UN's climate chief is worried humanity won't be able break its fossil fuel habit in time to avert catastrophe, she told AFP Thursday.

"My concern is whether the transformation is going to happen fast enough to avert the worst impacts," Christiana Figueres said, referring to the global shift from carbon-polluting fossil fuels to green energy.

"Greenhouse gas emissions have to peak quickly and descend," she said in an interview, as diplomats wrapped up their first negotiating session since hammering out the landmark pact in December.

"It is a race against the clock."

Figueres, from Costa Rica, took on the UN climate brief in the aftermath of the failed 2009 Copenhagen summit, and played a key role in laying the groundwork for the world's first universal climate deal.

Under the Paris Agreement, 195 nations vowed to hold average global warming to well under two degrees Celsius (3.6 degrees Fahrenheit), and even 1.5 C if possible.

Barely 1 C of warming so far has fuelled a crescendo of devastating droughts, super storms and rising seas threatening the homes and livelihoods of tens of millions.

But the tally of national pledges to curb greenhouse gases still falls far short of the mark, and scientists say they must be rapidly strengthened to hit the Paris goal.

Wealthy nations have also agreed to funnel trillions of dollars to poor countries in the coming decades to help them cope with climate impacts, and retool their economies.

Frontline negotiators tasked with converting the political blueprint into a workable plan met in Bonn for the 10-day session, and will reconvene along side their ministers in November in Marrakesh, Morocco.

Stepping down in July, Figueres was feted by the climate diplomats in a joint work session.

During the emotional send off, she was even regaled in song to the tune of a 1970s Abba hit as a "Climate Queen".

Famously -- some would say stubbornly -- upbeat, Figures told AFP that her six-year mandate was also filled with harrowing, make-or-break moments.

"I made a deliberate decision to be optimistic early on," she explained.

"It was in response to the situation that I inherited, which was anything but optimistic."

- Moments of crisis -

After the Copenhagen debacle, it was an open question whether the UN could get climate talks back on track.

Each of the six end-of-year climate meets she oversaw was laced with "moments of crisis," Figueres said.

During the 2011 summit in Durban, South Africa, where the 2015 Paris deadline was set, the press was reporting that the negotiations -- deep into overtime -- had failed, she recalled.

"That's when you have to take a deep breath," she said.

The December deal has ushered in a new spirit of cooperation between rich and developing nations that was often absent during more than 20 years of fraught talks, she added.

"There is much more willingness to address this problem collectively," she said, echoing the view of many diplomats and observers here.

But the Paris pact is only a framework and still needs to be fleshed out.

"It's like moving into a very large, unfurnished house" with 196 flatmates, Figueres said. "And all the decisions have to be made by consensus."

Figueres will be succeeded as Executive Secretary of the UN Framework on Climate Change by former Mexican minister Patricia Espinosa, currently ambassador to Germany.