From the UK’s University of Exeter, Professor Tim Lenton explains the climate niche where most of humanity lives. But that zone is shifting, and billions of humans will migrate away from uninhabitable countries, mostly northward toward the Poles – not centuries but mere decades from now. Dr. Radley Horton from Columbia University warns killer heat and humidity are already popping up around the world, including the United States. Human productivity, crops, and lives are lost, with more to come in a rapidly warming world. Like the virus, the greenhouse world doesn’t care if you believe it, deny it, or postpone action. Now we are in a race to keep as much earth as we can within limits dictated by our health.