How did this change happen? Over the last half-century, leftist intellectuals have identified two great scapegoats for the world’s woes. First, Marxism designated capitalism as responsible for human misery. Second, “Third World” ideology, disappointed by the bourgeois indulgences of the working class, targeted the West, supposedly the inventor of slavery, colonialism, and imperialism. The guilty party that environmentalism now accuses—mankind itself, in its will to dominate the planet—is essentially a composite of the previous two, a capitalism invented by a West that oppresses peoples and destroys the earth. Indeed, environmentalism sees itself as the fulfillment of all earlier critiques. “There are only two solutions,” Bolivian president Evo Morales declared in 2009. “Either capitalism dies, or Mother Earth dies.”

So the planet has become the new proletariat that must be saved from exploitation—if necessary, by reducing the number of human beings, as oceanographer Jacques Cousteau said in 1991. The Voluntary Human Extinction Movement, a group of people who have decided not to reproduce, has announced: “Each time another one of us decides to not add another one of us to the burgeoning billions already squatting on this ravaged planet, another ray of hope shines through the gloom. When every human chooses to stop breeding, Earth’s biosphere will be allowed to return to its former glory.” The British environmentalist James Lovelock, a chemist by training, regards Earth as a living organism and human beings as an infection within it, proliferating at the expense of the whole, which tries to reject and expel them. Journalist Alan Weisman’s 2007 book The World Without Us envisions in detail a planet from which humanity has disappeared. In France, a Green politician, Yves Cochet, has proposed a “womb strike,” which would be reinforced by penalties against couples who conceive a third child, since each child means, in terms of pollution, the equivalent of 620 round trips between Paris and New York.