The climate crisis, Donald Trump told the UN last month, is “the greatest con job ever perpetrated on the world”. With these words the US president rejected the international scientific consensus and evidence that we can all check daily with a basic thermometer. He has also announced he is withdrawing the US from the Paris climate agreement, signed in 2015 by 195 UN countries. The US joins an axis of deniers including Yemen, Iran and Libya, countries that signed the agreement but never ratified it.

Paradoxically, Trump’s reversal provides an opportunity for others to advance the climate agenda: to sketch out the blueprint of a possible new world order without the US, even if Washington was the architect of the old one.

A new arrangement could even emerge at the UN climate summit, Cop30, in Brazil next month. Success will depend on the leadership capability of an unlikely duo: the host country, which is one of the founding Brics nations, and the EU, still the core political community in a fractured western alliance.

There is almost always a grain of truth in what Trump claims. He is not totally wrong when he accuses the UN of being toothless. As he said in his speech: “All they seem to do is write a really strongly worded letter and then never follow that letter up.”

In 1995, Angela Merkel, then the German environment minister, opened the

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