That we reengineered the natural world so sufficiently to close the book on an entire geological era—that is the major lesson of the Anthropocene. The scale of that transformation remains astonishing, even to those of us who were raised amidst it and took all of its imperious values for granted. Twenty-two percent of the earth’s landmass was altered by humans just between 1992 and 2015. Ninety-six percent of the world’s mammals, by weight, are now humans and their livestock; just four percent are wild.
