For most of humanity, there’s no escape from the punishing effects of a warming planet. Adaptation is now a necessity. But how? What if wildfires keep raging out of control? What if huge swaths of the world’s farmland can’t support crops? What if some cities are no longer liveable? What if unbearable heat drives hundreds or millions to migrate? These are increasingly real scenarios, and they demand not just long-range planning but immediate action in order to mitigate them.