The European Parliament has voted to ratify the world's first comprehensive climate treaty, in a move that will see the deal come into force.
The European Union's ratification of the Paris Agreement, which commits countries to cutting greenhouse gas emissions to net zero to stop dangerous climate change, means the thresholds needed to bring it into force have been met.
The deal, secured in the French capital last December, comes into force 30 days after it has been ratified by at least 55 countries accounting for 55% of the world's emissions.
Already 62 countries accounting for 51.89% of global emissions, had ratified the deal, and the EU's move to ratify means its 12% of global emissions will ensure the second threshold is met.
In a session of the parliament attended by United Nations secretary general Ban Ki-moon, 610 MEPs voted in favour of adopting the agreement - while 38 voted against.
Before the vote, Mr Ban urged them to ratify the deal, saying: "At a time of record heat, let us take historic action.
"At a time of divisions on many other challenges, let us show we are united on the biggest one of all.
"This is our chance to set us on course to a safer, more sustainable future for all on a healthy planet."
European Commission president Jean-Claude Juncker said: "Today, the European Union turned climate ambition into climate action.
"The Paris Agreement is the first of its kind and it would not have been possible were it not for the European Union.
"Today we continued to show leadership and prove that, together, the European Union can deliver."
The EU joins major polluters including the US, China and India who have already ratified the deal - which will now come into legal force by the time the next round of UN climate talks take place in November in Marrakesh, Morocco.
Individual European countries can ratify alongside the EU if they are ready or join when their domestic processes are complete, with Prime Minister Theresa May pledging the UK will formally adopt the deal before the end of the year.
Shadow energy and climate change secretary Barry Gardiner said: "Today marks a decisive shift in the global effort to tackle dangerous climate change.
"By ratifying the Paris climate agreement collectively, European countries have brought this historic deal into force less than a year after it was reached.
"This is a clear sign of the political will to accelerate the transition to clean energy around the globe."
He called on the Government to urgently complete the domestic process for ratification in Parliament and set out a robust plan that allows the UK to meet its legal climate commitments.
The EU had been under pressure to speed up ratification of the treaty so that it could enter into force this year, much sooner than the originally-planned 2020 start date, to meet the urgent need to tackle greenhouse gas emissions.
It comes as the world faces another record warm year in 2016, with every one of the last 16 months to August reaching new record monthly highs across the planet.