TIM LENTON: I’m not the only climate scientist who would tell you that if we go to 3 degrees Celsius of warming later this century—which is roughly where we’re heading on current policies—or, if we’re unlucky, and the climate is more sensitive, and that turns out to be 4 degrees Celsius or even more, we see such fundamental changes in the habitability of large areas of the planet that we find it hard not to conclude that there could be some kind of major social disruption, and thus an economic breakdown.

You could think of it as a fifty-fifty chance of losing everything or having a major social collapse