The diplomatic hurdles Boris Johnson will face as he tackles climate change at UNGA

UK Prime Minister Boris Johnson has landed in New York - the city of his birth - in his first major overseas trip since the start of the Covid pandemic.

On the plane on the way over, he claimed relations with the US were as good as they had been in decades.

Despite his optimism, this is a trip strewn with diplomatic hurdles.

His visit to the White House will be the first since Joe Biden became US President - and also the first since the USA’s hasty withdrawal from Afghanistan.

There will certainly be discussions about Afghanistan’s future, but his focus is unlikely to be on any mistakes of the past, given the urgent need to secure present and future global cooperation to make COP26, the crucial climate summit in Glasgow, a success.

In a speech to the United Nations (UN) and in multilateral and bilateral meetings over the next few days, the prime minister will urge countries around the world to “step up to the plate” on climate.

The British government has identified its priorities for COP26 as cash, coal, cars and trees.

On the first, he has to try to persuade richer countries to stop falling short on their commitment to deliver £100 billion a year to help developing countries mitigate and adapt to climate change.

On the second, he has to encourage countries, particularly China, the world’s largest carbon emitter, to phase out the use of coal - all that against a backdrop of the recent defence pact with Australia and the US, which has enraged the Chinese.

It is perhaps no wonder that even this most optimistic prime minister gave his chances of getting the cash pledged only a six out of 10.

This is sobering when the UN has declared that COP26 must be the turning point on climate change, if the world is to avoid its most catastrophic consequences.