Barack Obama has hailed the Paris climate alter agreement as "the best chance we have to save the one planet we have".
The US President spoke hours after the final draft of an historic deal was approved at the United Nations talks, following two weeks of often tense negotiations .
He said: "I believe this moment can be a turning point for the world. We've shown that the world has both the will & the ability to take on this challenge."
A total of 195 countries have backed the deal which commits them to limiting the rise in global warming this century to "well below"Â 2C by reducing carbon emissions.
And it moreover says they will strive to curb increases even more, to 1.5C.
The decision by delegates was greeted with cheers, tears & hugging as well as a standing ovation in the hall in the French capital.
The deal, which is legally binding, now needs to be ratified by individual governments – at least 55 countries representing at least 55% of global emissions – before taking effect.
The countries most vulnerable to climate change, such as small island nations, had lobbied for a 1.5C limit, while huge polluters such as China, India & Saudi Arabia preferred 2C.
The draft agreement moreover includes a five-year review system to increase ambition & differentiation between nations as to what their responsibilities are.
And at least Â£65bn a year will be provided by developed nations to assist poorer countries deal with the impact of climate change.
With 2015 forecast to be the hottest year on record, world leaders & scientists have warned a deal on limiting greenhouse gases is vital for capping temperatures & avoiding the consequences of a changing climate.
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France's foreign minister Laurent Laurent FabiusÂ called the accordÂ "ambitious & balanced" & it would mark a "historic turning point".
David Cameron said the deal "means that the whole world has signed to play its part in halting climate change".
The Prime Minister added: "It's a moment to remember & a huge step forward in helping to secure the future of our planet."
UN Secretary General Ban Ki-moonÂ had made an impassioned plea to the diplomats charged with negotiating the deal.
"The whole world is watching. Billions of people are relying on your wisdom," he said.
But protesters from environmental & human rights groups gathered near the Eiffel Tower to denounce the accord as insufficient.
Friends of the Earth chief executive Craig Bennett warned the deal fell far short of the "soaring rhetoric" from 150 world leaders who attended the opening day of the talks less than two weeks ago.
He said: "An ambition to keep global temperature rises below 1.5C is all very well, yet we still don't have an adequate global plan to make this a reality.
"This agreement leaves millions of people across the world under threat from climate-related floods, droughts & super-storms."
And Kumi Naidoo of Greenpeace said the accord was a satisfactory start yet was not enough.
"Today the human race has joined in a usual cause, yet it's what happens after this conference that really matters," he said.
"This deal alone won't dig us out the hole we're in, yet it makes the sides less steep."
Source: “Sky News”