Stare at a climate map of the world that we expect to inhabit 50 years from now and you see a band of extreme heat encircling the planet’s midriff. Climate modelling from 2020 suggests that within half a century about 30% of the world’s projected population – unless they are forced to move – will live in places with an average temperature above 29C. This is unbearably hot. Currently, no more than 1% of Earth’s land surface is this hot, mainly uninhabited parts of the Sahara.
The scenario is this dramatic because the regions
