Thanks to the G7, there is a wind of change in the Cornish air – and Joe Biden is the man for this moment

Time was when the president of the United States would find it necessary to fly in to a summit somewhere in the Middle East to knock heads together and coax squabbling neighbours towards some lasting political settlement. This time, President Biden is in the bizarre position of having to do the same with the British and their neighbours in the European Union. All should wish him luck in that enterprise, and not to allow these continuing tensions to distract from giving a firm lead on climate change. After the Trump interregnum, America is indeed back to work – and not a moment too soon.

If there is a “special relationship” between Boris Johnson and Joe Biden, then it doesn’t seem to be a specially close one, though undeniably US-UK relations are growing especially complicated. It will be difficult – though not impossible – for these two very different personalities to make the best of the very difficult challenges ahead of them, notably the situation on Northern Ireland and climate change.

President Biden has made little attempt to disguise his contempt for Brexit as a project, and the threat it poses to peace in Ireland. He once remarked that Mr Johnson is a kind of English “clone” of Donald Trump, which says it all. The US has served a “demarche” on the UK because of its reckless disregard for the UK-EU Withdrawal Agreement and the Good Friday Agreement.

Mr Johnson joked, on Mr Biden’s election, that the new president was one of the few world leaders he hadn’t got around to insulting. Since then he has been turning on the charm – and just as well.

Both, though, should be level-headed enough to compartmentalise their differences and their agreements – there need not be any diplomatic linkage between Brexit and taking a lead on climate change – something that must also apply to presidents Macron and Von der Leyen and Chancellor Merkel. Mr Biden has been careful to avoid stirring up the Brexit arguments in public (he’ll still be insistent in private) and to talk up the new “Atlantic Charter”.

Unlike his predecessor, Mr Biden has a sense of decorum, and of perspective. The climate emergency is, after all, the transcendent issue facing the planet; and rather more portentous than Britain’s trading arrangements with the European Union – or even the Irish peace process.

Fortunately there is every indication that the G7 – representing most of global GDP – will indeed take a lead on limiting emissions of greenhouse gases, another step on the road to the COP26 conference on Glasgow in November.

For the first time in many years there is a real sense of international purpose on the environment, with even China and Russia now conceding at least the problem exists.

Remarkably, too, with US leadership, the scandal of global corporate tax avoidance may be drawing to an end. There is a wind of change in the Cornish air, and a moment of optimism as the world struggles to emerge from its plague. Mr Biden is the man for this moment.