A triple inequality lies at the heart of the climate emergency

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.

- Adam Tooze

The scenario is this dramatic because the regions affected most severely by global heating - above all, sub Saharan Africa - are those expected to experience the most rapid population growth in coming decades.

But despite this population growth, they are also the regions that, on current trends, will contribute least to the emissions that drive the climate disaster. So extreme is inequality that the lowest-earning 50% of the world population - 4 billion people - account for as little as 12% of total emissions. And those at the very bottom of the pile barely register at all. Mali's per capita CO2 emissions are about one-seventy-fifth of those in the US.

Even if the lowest-earning third of the global population - more than 2.6 billion people were to raise themselves above the $3.2-a-day poverty line, it would increase total emissions by a mere 5% - that is, one-third of the emissions of the richest 1%.

Half the world's population, led by the top 10% of the income distribution - and, above all, by the global elite - drive a globe-spanning productive system that destabilises the environment for everyone. The worst effects are suffered by the poorest, and in the coming decades the impact will become progressively more extreme. And yet their poverty means they are virtually powerless to protect themselves.