Wolfgang Cramer’s first involvement with the Intergovernmental Panel on Climate Change was in the 90s. He worked on the second assessment report, delivered in 1995, which affirmed the science of anthropogenic climate breakdown. At that point, no one could say they did not know what was happening.

Almost three decades on, Cramer was part of the international scientific team that prepared the sixth IPCC report. Its conclusion, delivered in March, issued human civilisation a bleak “final warning” – the biosphere stands on the brink of irrevocable damage.

Now, as diplomats meet in Dubai for the 28th round of the Cop climate talks, in a year predicted to be the hottest on record, and as carbon emissions continue to rise, Cramer is one of 33 IPCC authors among 1,447 scientists and academics in signing an open letter calling on the public to take collective action to avert climate breakdown.

“We are terrified,” they warn. “We need you.”