Global climate envoys agreed a landmark accord on Saturday, setting the course for a "historic" transformation of the world's fossil fuel-driven economy within decades in a bid to arrest global warming.

At the tail end of the hottest year on record and after four years of fraught UN talks often pitting the interests of rich nations against poor, imperilled island states against rising economic powerhouses, French Foreign Minister Laurent Fabius took just minutes to declare the pact adopted to the standing applause and whistles of delegates from almost 200 nations.

Hailed as the first truly global climate deal, committing both rich and poor nations to reining in rising emissions blamed for warming the planet, it sets out a sweeping long-term goal of eliminating net man-made greenhouse gas output this century.

It also creates a system to encourage nations to step up voluntary domestic efforts to curb emissions, and provides billions more dollars to help poor nations cope with the transition to a greener economy.

Calling it "ambitious and balanced", Fabius said the accord would mark a "historic turning point" in efforts to avert the potentially disastrous consequences of an overheated planet.

In some ways its success was assured before the summit began: 187 nations have submitted detailed national plans for how they will contain the rise in greenhouse gas emissions, commitments that are the core of the Paris deal.

While leaving each country to pursue those measures on its own, the agreement finally sets a common vision and course of action after years of bickering over how to move forward.

Earlier in the evening, the climate negotiators from key nations including India, Brazil and Venezuela signalled they would not block a landmark accord due to be discussed later on Saturday in Paris.

Indian environment minister Prakash Javadekar, who had championed the need for rich nations to step up financing for the developing world, said he was happy with the deal.

"It is a balanced text," said Izabella Teixeira, Brazil's environment minister. "In the case of Brazil we have a good text and we can accept it."

Claudia Salerno from Venezuela, one of several delegates who blocked a UN climate deal six years ago in Copenhagen, told Reuters she is "happy" with the agreement.-Reuters