Drawing on the author's recent book Ethics for a Broken World, this article explores the philosophical implications of the fact that climate change – or something like it – might lead to a broken world where resources are insufficient to meet everyone's basic needs, and where our affluent way of life is no longer an option. It argues that the broken world has an impact, not only on applied ethics, but also on moral theory. It then explores that impact. The article first argues that the broken world creates severe difficulties for both libertarians and contractualists. It then explores the impact of the broken world on utilitarianism – and especially on reflective equilibrium arguments for rule-utilitarianism. The article concludes that, while such arguments may still be viable, the form of rule-utilitarianism that results will be less moderate and less liberal than contemporary rule-utilitarians might hope.