A landmark agreement on climate change will enter into force on Nov. 4, backed by a coalition of the world's largest polluters and small island nations threatened by rising seas.
U.N. Spokesman Farhan Haq said the EU, Canada and Nepal are all expected to deposit their instruments of ratification over the course of the day Wednesday, edging the percentage of emissions by ratifying countries past the 55 per cent threshold needed for the treaty to take effect.
"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," Secretary Ban Ki-moon said in a statement issued from Europe. "Global momentum for the Paris Agreement to enter into force in 2016 has been remarkable. What once seemed unthinkable is now unstoppable. "
The deal takes effect 30 days after 55 countries, accounting for at least 55 per cent of global emissions, have adopted it. Sixty-two countries had done so as of Tuesday but they accounted only for about 52 per cent of emissions.
With the addition of Nepal, Canada and the seven EU countries that have so far ratified the deal, the countries now account for and estimate 58.7 per cent of emissions.
A U.N. website said currently 72 of the 197 parties to the treaty, accounting for 56.75 of the world's greenhouse gas emissions have officially ratified. It wasn't clear if all the parties that had planned to deposit their ratifications Wednesday, which may account for the discrepancy.
"It's clearly a momentous moment in terms of global action on climate change," said David Waskow, international climate director at World Resources Institute. "This has been much more rapid than anticipated and demonstrates political support for the agreement."
The Paris agreement commits rich and poor countries to take action to curb the rise in global temperatures that is melting glaciers, raising sea levels and shifting rainfall patterns. It requires governments to present national plans to reduce emissions to limit global temperature rise to well below 2 degrees Celsius (3.6 degrees Fahrenheit).
While the targets in the agreement are not legally binding, the treaty does require countries to report on emissions and their progress on reaching the goals in the national climate plans they submitted to the U.N. The countries are also required to maintain those plans, update them every five years and to pursue measures to implement their stated goals.
The accord, which was adopted by consensus on Dec. 12, 2015, has entered into force at what is considered in the world of international diplomacy, a blistering pace, reflecting a sense of urgency in the fight against global warming and a desire to seal the deal before Secretary General Ban Ki-moon and U.S. President Barack Obama leave office.
Democratic presidential candidate Hillary Clinton supports the accord, while Republican Donald Trump opposes it.
Obama welcomed the news, speaking in the Rose Garden, saying that if nations follow through on their commitments under the agreement, "history may well judge it as a turning point" for the planet.
International momentum had been building to ensure that the deal could enter force by the next U.N. climate conference, which starts Nov. 7 in Marrakech, Morocco.
Morocco's Ambassador of Multilateral Negotiations Aziz Mekouar said with the treaty entering into force before Nov. 7, Marrakech will now host the first Conference of Parties to Paris Agreement.
"Last year, it was an historic event," Mekouar said, referring to the conference where the agreement was first adopted. "This year, it's even more of an historic event."
Michael Oppenheimer, a professor of geosciences at Princeton University, said the treaty entering into force is great news, but warned there's a long road ahead.
"There's a lot of hard work ahead to fulfil the main Paris goal, avoiding dangerous climate change. Without focused efforts starting now, we are not going to avoid falling over a very steep cliff," Oppenheimer said in an email.