UN Secretary-General Ban Ki-moon on Saturday congratulated the signatories of the Paris climate change accord which he called a "monumental triumph for people and the planet".

Ban said this while the political dignitaries and guests at the Paris United Nations conference on climate change (COP21) went into an emotional outburst of joy, hugging each other and some even shedding tears of joy, as one UN diplomat put it.

In a tweet immediately following the agreement, Ban also said that the accord had set the stage for progress in ending poverty, strengthening peace and ensuring a life of dignity and opportunity for all."

French Foreign Minister, Laurent Fabius, who has been the president of the COP21, publicly announced the historic breakthrough, evoking a thunderous applause with the guests standing up to welcome the news.

This was a remarkable achievement because of the unanimity of the accord.

Every country in the world - all 196 parties to the UN Framework Convention on Climate Change (UNFCCC) - pledged to curb emissions, strengthen resilience and join to take common climate action. The accord had been preceded by a fortnight of tireless negotiations at the COP21.

Ban spoke of an unprecedented leadership demonstrated by the world leaders.

"In the face of an unprecedented challenge, you have worked collaboratively to achieve something that no one nation could achieve alone. This is a resounding success for multilateralism," he said as he took centre stage to speak just a few minutes after the breakthrough accord.

Pointing out that climate change had been one of the defining priorities of his tenure as Secretary-General, Ban said that most of all, he had listened to people - the young, the poor and the vulnerable, including indigenous peoples, from every corner of the globe.

These people, Ban added, had sought protection from the perils of a warming planet, and the opportunity to live in a safer, more bountiful world.

"They have demanded that world leaders act to safeguard their well-being and that of generations to come."

Referring to the accord, he said the negotiators reached solid results on all key points, with an agreement that demonstrated solidarity and was ambitious, flexible, credible and durable.

"All countries have agreed to hold global temperature rise to well below two degrees Celsius. And recognising the risk of grave consequences, you have further agreed to pursue efforts to limit temperature increase to 1.5 degrees," he announced.

Review mechanism created

A review mechanism was also created so that, every five years, starting 2018, the parties to the agreement will regularly review if additional measures are needed in conformation with science.

Underlining the important role played by the private sector to curb emissions, Ban pointed out that business leaders had come to Paris in unprecedented numbers and that "powerful" climate solutions were already available and many more would come.

"With these elements in place, markets now have the clear signal they need to unleash the full force of human ingenuity and scale up investments that will generate low-emission, resilient growth," he said, adding that what was once unthinkable had now become unstoppable.

"When historians look back on this day, they will say that global cooperation to secure a future safe from climate change took a dramatic new turn here in Paris.

"Today, we can look into the eyes of our children and grandchildren, and we can finally say, tell them that we have joined hands to bequeath a more habitable world to them and to future generations."

Ending his remarks, the UN chief said that all parties should be proud of the Paris Agreement and that "the work starts tomorrow".

"For today, congratulations again on a job well done," he concluded. "Let us work together, with renewed commitment, to make this a better world."

Though the mood at the UN and also within the United States had been one of uncertainty, with officials fearing a last-minute ditch by one or two leaders, things took a much calmer turn as the day progressed.

During the earlier of Saturday, at a meeting of the Committee of Paris, the body which was overseeing the COP21 negotiations, the UN chief spoke alongside French President François Hollande and Foreign Minister Fabius.

"The end is in sight. Let us now finish the job. The whole world is watching. Billions of people are relying on your wisdom," the Secretary-General urged delegates.

An emotional Fabius, unable to hide his tears and in a stuttering voice, said the agreement would serve meaningful causes, food safety and security, public health, the fight against poverty and for essential rights, and therefore peace.

Hollande, while concluding the gargantuan conference, reminded the guests that "it is rare to be given the opportunity to change the world. You have the opportunity to do that."

- Bernama