British Prime Minister Boris Johnson travelled to the US on Sunday with senior Cabinet officials to urge world leaders attending the UN General Assembly to act urgently on climate change.
Mr Johnson, who will host November's Cop26 summit in Scotland, will co-host a meeting on climate change with UN Secretary General Antonio Guterres on Monday.
The two will discuss the need to help developing countries ease the effects of climate change.
“This week, as world leaders arrive in New York for the biggest diplomatic event of the year, I will be pushing them to take concrete action on coal, climate, cars and trees, so we can make a success of Cop26 and keep our climate goals within reach,” Mr Johnson said.
However, he admitted he had only a “six out of 10” chance of getting world leaders to hit a key pledge before Cop26 starts next month.
He conceded it will be “tough” to get allies to live up to their promise to give £73 billion ($100bn) a year in support to developing nations to cut their carbon emissions.
But Mr Johnson was doubtful that he would be able to get leaders to hit the target by Cop26 as he urged them to “step up to the plate” and part with more cash.
“I think getting it all done this week is going to be a stretch,” he told reporters during the flight to New York.
“But I think getting it all done by Cop: six out of 10. It’s going to be tough but people need to understand that this is crucial for the world.”
Britain is hosting the UN's climate summit from November 1 to November 12 in Glasgow.
The conference is being presented as a crucial moment to persuade governments, industry and investors to make binding commitments on reducing greenhouse gas emissions, and make progress on reducing global warming to below 1.5°C above pre-industrial levels.
The British government says 100 world leaders have confirmed they will attend the conference.
But Alok Sharma, the president of the conference, was not able to confirm on Sunday whether Chinese President Xi Jinping has committed to attending, or whether China would send a delegation.
“On the issue of whether Xi Jinping is going to come, that is not yet confirmed," Mr Sharma told the BBC.
"Normally these things come a bit closer to summits. I am very, very hopeful that we will have a delegation from China."
Beijing, as the world’s biggest greenhouse gas emitter, would have to play a key part in any climate change agreement, he told Sky News.
“They have said to me they want the Cop26 to be a success," Mr Sharma said. "The ball is in their court.
"We want them to come forward and make it a success together with the rest of the world."
Mr Johnson, Mr Sharma and newly appointed British Foreign Secretary Liz Truss arrived in New York on Sunday for a four-day visit to the US.
After the UN General Assembly, Mr Johnson and Ms Truss will visit the White House for talks on climate change, the pandemic and international security.
It will be Mr Johnson’s first visit to the White House since US President Joe Biden took office.