Grist: In 2002, architect William McDonough and chemist Michael Braungart shook up the world of sustainability with their book Cradle to Cradle: Remaking the Way We Make Things. It proposed a radical rethinking, not just of human manufacturing, but of the way humans relate to the earth. Rather than simply reducing the harm we do, humans could become a source of health, a positive force in the world. The iconic example was a tree. A tree is not "efficient," it is abundant, generative, sustaining its own...