In February 2000, Paul Crutzen rose to speak at the International Geosphere-Biosphere Programme in Mexico. And when he spoke, people took notice. He was then one of the world’s most cited scientists, a Nobel laureate working on huge-scale problems – the ozone hole, the effects of a nuclear winter.

So little wonder that a word he improvised took hold and spread widely: this was the Anthropocene, a proposed new geological epoch, representing an Earth transformed by the effects of industrialised humanity.

The idea of an entirely new and human-created geological epoch is a sobering scenario as context for the current UN climate summit, COP28. The impact of decisions made at these and other similar conferences will be felt not just beyond our own lives and those of our children, but perhaps beyond the life of human society as we know it.