Norman Daniels, in applying Rawls' theory of justice to the issue of human health, ideally presupposes that society exists in a state of moderate scarcity. However, faced with problems like climate change, many societies find that their state of moderate scarcity is increasingly under threat. The first part of this essay aims to determine the consequences for Daniels' theory of just health when we incorporate into Rawls' understanding of justice the idea that the condition of moderate scarcity can fail. Most significantly, I argue for a generation-neutral principle of basic needs that is lexically prior to Rawls' familiar principles of justice. The second part of this paper aims to demonstrate how my reformulated version of Daniels' conception of just health can help to justify action on climate change and guide climate policy within liberal-egalitarian societies.