Climate change is changing not only our physical world, but also our intellectual, social, and moral worlds. We are realizing that our situation is profoundly unsafe, interdependent, and uncertain. What, then, does climate change demand of economists, as human beings and as professionals? A discipline of economics based on Enlightenment notions of mechanism and disembodied rationality is not suited to present problems. This essay suggests three major requirements: first, that we take action; second, that we work together; and third, that we focus on avoiding the worst, rather than obtaining the optimal. The essay concludes with suggestions of specific steps that economists should take as researchers, teachers, and in our other roles.