The Prime Minister has heralded Joe Biden’s commitment to double the US’s climate finance as a “very good start” towards his goal of securing 100 billion dollars from world leaders to tackle global warming.

Boris Johnson, who has been urging leaders at the United Nations gathering in New York to stump up more money for climate action, said the president’s funding pledge would take them “a long way towards” his target.

Mr Biden made the announcement at the UN on Tuesday as he acknowledged “we’re fast approaching a point of no return”.

Speaking to reporters on the platform at Washington DC’s Union Station, the Prime Minister said: “This is very good news in the sense the United States has stepped up to the plate with a massive contribution.

“That’s a very, very good start.

“It means we’re a long way towards the goal we need to achieve, but there’s still a long way to go.

“There’s no question that this American action today has been a big lift and will really help us to get there.”

As the Prime Minister was travelling to the White House, Mr Biden told the summit in New York he would seek to double funds for helping developing nations with climate change.

That would bring the US’s total to 11.4 billion dollars per year, or £8.3 billion, as Mr Johnson pushes for leaders to live up to their commitment to give equivalent to £73 billion per year.

A No 10 spokesman said: “The Prime Minister obviously welcomes the financial commitment that the president has just made on tackling climate change.

“You heard the PM yesterday calling for developed countries to put more money forward in regard to this.”

The Prime Minister had earlier downplayed the chances of hitting the 100 billion dollar target by the Cop26 conference in Glasgow in November.

Mr Biden said he would work with the US Congress to double the contribution again, including funding to help poorer countries to adapt to the impacts of rising global temperatures.

He said the move would, with increased private finance and contributions from other donors, mean developed countries meet the long-promised goal of delivering 100 billion dollars a year for developing countries to deal with the crisis.

Meeting the pledge, first made at climate talks in Copenhagen in 2009, is seen as key to securing a successful outcome at the UN’s key Cop26 summit in Glasgow in November, where countries are under pressure to increase action to avoid the worst impacts of an overheating world.

Mr Biden said: “Scientists and experts are telling us that we’re fast approaching a point of no return.

“To keep within our reach the vital goal of limiting global warming to 1.5C, every nation needs to bring the highest possible ambitions to the table when we meet in Glasgow for Cop26, and then have to keep raising our collective ambition over time.”

Of the pledge to further double climate funding, Mr Biden said: “This will make the United States a leader in public climate finance.

“With our added support, together with increased private capital, and from other donors, we’ll be able to meet the goal of mobilising 100 billion to support climate action in developing nations.”