President Donald Trump has once again vowed to withdraw the US from the Paris climate agreement, the world's most important effort to tackle rising temperatures. The first Trump administration made a similar move in 2017, but that step was promptly reversed on President Joe Biden's first day in office in 2021.

The US will now have to wait a year before it will be officially out of the pact. The White House announced a "national energy emergency", outlining a raft of changes that will reverse US climate regulations and boost oil and gas production.

It comes after global temperatures in 2024 rose more than 1.5C above pre-industrial levels for the first time in a calendar year. While the Paris agreement is not a legally binding treaty, it is the document that drives global co-operation to limit the causes of global warming.

President Trump's antipathy to this co-operative approach was echoed in his statement in 2017 that he had been elected to "represent the people of Pittsburgh and not Paris".

This temperature threshold was established in the Paris agreement as a level beyond which the world would face extremely dangerous impacts.

The US will now join Iran, Yemen and Libya as the only countries to currently stand outside the agreement, which was signed 10 years ago in the French capital.

At the White House on Monday evening, Trump signed the order to withdraw from the Paris climate accord, including a letter to the United Nations explaining the decision.

He also announced a "national energy emergency" to reverse many of the Biden-era environmental regulations. Trump called the Paris agreement a "ripoff" during a speech at the Capital One Arena in Washington, DC, following his swearing-in.

"We will drill, baby, drill," he said earlier in his inaugural address. The new president also vowed the US would embark on a new age of oil and gas exploration.