The most powerful and cogent critique that can currently be leveled against our mode of capitalism is that markets fail to account for ecological costs. In a crowded world of finite size, our political economy values only acceleration and expansion. Scarce natural resources like clean air and water, not to mention more complex systems like rainforests or coral reefs, are either held at nothing or seriously undervalued. Corporations could clear-cut all our forests, reduce croplands to swirling dust, turn rivers to conveyors of toxic sludge, deplete supplies of minerals and metals, double and redouble carbon emissions—and all our economic indicators would show nothing but robust growth until the very moment the pyramid scheme collapsed. Indeed, most of these things are happening, with only scattered opposition. When our math improves, when the costs of our products fully reflect the resources used and the wastes produced—especially CO2: then and only then can capitalism begin to become a viable and humane economic system.