 For 200 years, industrial activity has been based on degenerative design. We take Earth's materials, make them into stuff we want, use it for a while and then toss it away. Take, make, use, lose. It's a one-way system that runs counter to the living world and it's devouring the sources of its own sustenance. Economic theory has told us not to worry that more growth is needed so that nations can afford to clean things up. But at the global scale, that's simply not true. And the effects are destroying Earth's life support systems on which we all fundamentally depend. We can't wait for growth to clean things up because it won't. We need to turn today's economies which are degenerative by default into ones that are regenerative by design. Ones that run on renewable energy, that turn waste from one process into food for the next. So that things are never used up, but are used again and again. And in all this, the 21st century Economist's role is a crucial one to harness the potential of business and finance, of the commons and the state and of human nature to unleash this regenerative future.