The Paris Climate Agreement will go into effect on November 4 after the final threshold for its entry into force has been reached, UN Secretary General Ban Ki-moon said Wednesday.
With 72 countries accounting for more than 56 per cent of global greenhouse emissions having ratified the deal, the last hurdle has been cleared triggering the agreement's entry into force in 30 days.
"I am delighted to announce that today the Paris Agreement will cross the second and final threshold needed for entry into force, and will enter into force on 4 November 2016," Ban said.
"Global momentum for the Paris Agreement to enter into force in 2016 has been remarkable. What once seemed unthinkable is now unstoppable."
The agreement, struck in the French capital in December, is aimed at keeping global temperature increases to within two degrees of pre-industrial levels.
The deal's pledges are binding from 2020.
US President Barack Obama welcomed the announcement noting that the deal was "the best possible shot to save the one planet we've got."
"Today is a historic day in the fight to protect our climate for future generations," Obama said.
The deal was triggered to enter into force after the European Union, seven EU states and other countries handed over documents ratifying the climate agreement to the United Nations, which is the last step for countries towards officially joining the agreement.
Questions remain about whether the countries' individual plans to curb emissions will keep global temperatures below the agreed-upon sub-two-degree limit.
Scientists have warned that ambitions should be ramped up over the coming years.