The US has begun the process of withdrawing from the Paris Agreement, notifying the UN of its intention to leave, as other countries expressed regret and disappointment at the move.
The notification begins a one-year process of exiting the global climate change accord, culminating the day after the 2020 US election.
The US government says the deal puts an “unfair economic burden” on Americans.
The agreement brought together 188 nations to combat climate change.
France and Japan have led international condemnation of the US move.
The Paris accord, agreed in 2015, committed the US and 187 other countries to keeping rising global temperatures below 2C above pre-industrial levels and attempting to limit them even more, to a 1.5C rise.
The decision to withdraw – taken by President Donald Trump after he came to office in 2017 – made the US the world’s sole non-signatory and prompted high-level efforts by the European Union to keep the agreement on track.
However, hundreds of local governments, businesses and organisations in the US have joined the We Are Still In movement, pledging to cut emissions and move to renewable energy.
UN climate envoy and US entrepreneur Michael Bloomberg said in a statement posted on the movement’s website that he was working to fill the funding gap left by the Trump administration’s withdrawal, which he described as an “abdication of leadership”.
Mr Trump had made withdrawing from the agreement one of his election campaign pledges but UN rules had meant it was not possible for the US to start the withdrawal process until 4 November 2019.
The withdrawal is still subject to the outcome of next year’s US presidential election – if Mr Trump loses, the winner may decide to change course.
A report issued in December 2018 by the Institute of International and European Affairs suggested President Trump’s decision to leave had done “very real damage” to the Paris agreement, creating “moral and political cover for others to follow suit”.
What reaction has there been?
The decision by the US – one of the world’s biggest emitters of greenhouse gases – drew condemnation from environmentalists and expressions of regret from world leaders.
An official for France’s presidential office said “we regret this and this only makes the Franco-Chinese partnership on the climate and biodiversity more necessary.”
French President Emmanuel Macron and his Chinese counterpart Xi Jinping are due to meet in Beijing on Wednesday, where they are expected to sign a statement declaring the “irreversibility of the Paris accord”, the official added.