A favorite trick of people who consider themselves friends of the environment is reframing luxury consumption preferences as gifts to humanity. A new car, a solar-powered swimming-pool heater, a 200-mile-an-hour train that makes intercity travel more pleasant and less expensive, better-tasting tomatoes—these are the sacrifices we're prepared to make for the future of the planet.

Our capacity for self-deception can be breathtaking. In 2010, a forward-thinking friend of mine took me for a ride in a Ford...