Juan Enriquez says we may have to air condition the planet by a degree or two while net zero catches up. Neither of us likes geoengineering. We like extinction even less.

We get into runaway methane, the climate history buried in Greenland ice cores, volcanic shade, Stephen Salter’s cloud ships, reflective drones, and the political problem behind any planetary intervention. The science needs to exist before catastrophe turns a bad idea into the only idea left.