The United Nations Secretary-General, Antonio Guterres, was one of the first to officially welcome President Biden’s signature of the protocol for the United States’ return to the Paris Agreement. This morning, as soon as the UN was notified of the signature, Guterres underlined its significance: “Following last year’s Climate Ambition Summit, countries producing half of global carbon pollution had committed to carbon neutrality. Today’s commitment by President Biden brings that figure to two-thirds”. “But there is a very long way to go”, Guterres added, because “the climate crisis continues to worsen and time is running out”. Guterres also looks “forward” to “the leadership of the United States in accelerating global efforts towards net zero”, both by bringing forward its national action plan, and by contributing to climate finance in advance of COP26 in Glasgow in November 2021. “I am committed to working closely with President Biden and other leaders to overcome the climate emergency, and recover better from COVID19”, Guterres concluded. Even European Commission Vice President Frans Timmermans welcomed the news on behalf of the EU: “We are looking forward to having the United States again at our side in leading global efforts to combat the climate crisis”, a challenge that “can only be tackled by combining all our forces”. “The whole planet will win” only if “all countries join a global race to zero emissions”. The Agreement, in compliance with its provisions, will enter into force for the United States on the thirtieth day after the date on which it was signed, that is to say, on 19 February 2021.