After a three-year delay, the USA on 4 November became the first country to formally withdraw from the Paris climate agreement.

Outgoing US President Donald Trump announced the move in June 2017, but UN regulations meant the decision did not take effect immediately. Under article 28 of the Paris Agreement, a Party may withdraw at any time after three years from the date on which the accord has entered into force for that Party, and such withdrawal takes effect upon expiry of one year from the date of receipt by the Depositary of the notification of withdrawal. The USA had accepted the Paris Agreement on 3 September, 2016 and it entered into force on 4 November that year.

The UN Climate Change secretariat said it "remains committed to working with all US stakeholders and partners around the world" as it noted that the USA's withdrawal from the Paris Agreement three years ago had formally come into effect.

In a joint statement with Chile, France, Italy and the UK, it said: "There is no greater responsibility than protecting our planet and people from the threat of climate change." The joint statement noted "with regret" that the US withdrawal from the Paris Agreement had formally come into effect, adding, "As we look towards COP26 in Glasgow, we remain committed to working with all US stakeholders and partners around the world to accelerate climate action, and with all signatories to ensure the full implementation of the Paris Agreement."

The UN was this year forced to postpone COP26 – its latest global climate change conference – because of the COVID-19 pandemic. It will be held in Glasgow, Scotland, in November 2021, and will be hosted by the UK in partnership with Italy.

"The science is clear that we must urgently scale up action and work together to reduce the impacts of global warming and to ensure a greener, more resilient future for us all," the statement read. "The Paris Agreement provides the right framework to achieve this. Our efforts must include support for those countries and communities at the frontline of climate change. It is vital that we take renewed action to hold the temperature rise to well below 2 degrees Celsius and take best efforts to limit warming to 1.5 degrees." The Paris Agreement marks its fifth anniversary on 12 December.

The USA could re-join the Agreement at any time in future, and President elect Joe Biden has indicated that he plans to do so.