Solomon Hsiang, a professor of public policy at the University of California, Berkeley and co-director of the university’s Climate Impact Lab, described being stuck inside as smoke filled the sky, and walking around his home with a hand-held air-quality indicator to find out which rooms had the worst air. “Everyone who could leave town has left town,” he said. Climate change in California is more than just an escalating series of short- and long-term disasters, Dr. Hsiang said. It’s also eroding the idea that the state can mold itself into whatever it wants to be, insulated from the physical threats around it. “California was the land of opportunities,” Dr. Hsiang added. “There’s this story that we can have it all, and that’s just not true.”