The landmark Paris climate deal will enter into force in 30 days, after being ratified by 72 countries accounting for more than 56 percent of global greenhouse gas emissions, the UN's climate body said.
"On October 5, 2016, the threshold for entry into force of the Paris Agreement has been achieved," the UNFCCC announced on its website.
Inked outside the French capital in December by 195 nations, the world's first universal climate treaty vows to cap global warming at well under two degrees Celsius.
At least 55 countries accounting for 55 percent of heat-trapping emissions needed to ratify the pact before it could go into force.
The European Union, which signed as a single party, and some EU member states have now pushed it over that threshold.
"The EU and European countries that have already ratified the agreement at a national level have now also submitted ratification documents to the UN," French environment minister Segolene Royal told AFP.
The move was widely hailed.
"This is a welcome development after years of frustratingly slow progress," said Andrew Steer, president of the World Resources Institute, a Washington-based thinktank.
"With the agreement in full force, countries can shift their focus from commitment to action.
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