Rising sea levels may sink entire countries. Individualistic solutions to this climate catastrophe, such as those proposed by Meisels and Risse, are inadequate on both Kantian and Lockean criteria. This article concurs with Cara Nine's recent argument that such ‘ecological refugee states’ are entitled to territorial remedies. But Nine's proposal, founded on Locke's ‘sufficiency’ proviso and Nozick's famous application of it to waterholes in the desert, is instructively incorrect. Careful consideration of the distinction between land and territory, and of the structure of Proviso arguments, supports a new theory of how territorial claims can be positive-sum — how the amount of territory can increase even as the land base remains constant or decreases. This normative conception of territory as the ratio of justice to land use provides a better foundation for a political solution to the problem of ecological refugee states and also generates deeper insight into the nature of territory itself. The article thus contributes not only to our thinking about redress for ecological refugees, but also to the burgeoning literatures on territory and on the Lockean Provisos.