The United States has joined China to formally ratify the Paris agreement to curb climate-warming emissions, the world's two biggest economies said on Saturday, which could help put the pact into force before the end of the year.
U.S. President Barack Obama and Chinese President Xi Jinping submitted their plan to join the agreement to U.N. Secretary-General Ban Ki-moon, who is in China to witness the announcement.
Senior Obama adviser Brian Deese said the joint declaration should push other countries to formally join the agreement.
"The signal of the two large emitters taking this step together and taking it early, far earlier than people had anticipated a year ago, should give confidence to the global communities and to other countries that are working on their climate change plans, that they too can move quickly and will be part of a global effort," Deese told reporters on Friday.
India is also poised to join the agreement this year, Deese said, adding that Obama was expected to meet Indian Prime Minister Narendra Modi on the sidelines of a Group of 20 nations meeting in Hangzhou, China, this weekend.
Obama and Xi committed to cooperate on two other global environmental agreements this year — an amendment to the Montreal Protocol to phase down air-conditioning refrigerants and on a market-based measure to reduce carbon emissions from aviation.