Donald Trump on Monday moved to withdraw the US, the world’s second biggest emitter of planet-heating pollution, from the Paris climate agreement for a second time, and put the United Nations on notice.

On his first day back as president, Trump signed an executive order on stage in front of supporters at an arena in Washington DC which he said was aimed at quitting what he called the “unfair one-sided Paris climate accord rip off”.

He also signed a letter to the United Nations giving it notice that the US was exiting, which starts the formal process of withdrawal from the world’s main effort to mitigate the worst impacts of the climate crisis.

It will take about a year for the withdrawal to be formalized.