Climate change and other global environmental problems constitute a significant challenge to contemporary political philosophy, especially with respect to complacency. This paper assesses Rawls' theory, and argues for three conclusions. First, Rawls does not already solve such problems, and simple extensions of his theory are unlikely to do so. This is so despite the rich structure of Rawls' philosophy, and the appeal of some of its parts. Second, the most promising areas for extension - the circumstances of justice, the duty to maintain and promote just institutions, and his vision of social development - are those that have not yet been explored. Third, unfortunately, Rawls' views on these topics are both seriously underdeveloped, and largely stipulative. Hence, in trying to meet climate change, Rawlsians are more likely to add new theories to Rawls, and perhaps even to transform his original account, than to generate an approach "from the inside out".