Paul Ehrlich, the celebrity bug scientist-turned-environmentalist who wrote a tract against babymaking called The Population Bomb, was disastrously wrong and never really admitted it. He spent his life defending The Population Bomb and saying he wished he had been more strident in it.

He predicted mass starvation as a consequence of a growing population, but the opposite happened: When the population grew, hunger dissipated. Now we face a crisis of low birth rates, and we are on the verge of a shrinking population.