The international climate change regime has failed. Even the most optimistic assessment of action to limit greenhouse pollution in the coming few decades will not prevent calamitous changes in Earth's climate. Arguments for international—that is, interstate—justice that have permeated international negotiations on climate change have been insufficient in fostering robust action by states. Indeed, by diverting all responsibility to states, focusing on international justice has not addressed consumption and pollution by hundreds of millions of affluent people around the world, including many millions living within developing states that have no treaty obligations to limit nationwide pollution. Increasingly, however, it is these individuals that matter: more and more of them who are not now subject to any climate-related legal obligations are able to afford lifestyles that lead to greenhouse gas emissions and more climate change. This is especially true given the very rapid increase in the numbers of affluent people in the developing world. Bearing this in mind, this article goes beyond the still important questions of international climate justice to explore cosmopolitan or global climate justice. Global justice demands that affluent individuals in both affluent and poor states do much more to limit their pollution of the atmosphere. By being good global citizens, capable persons can help states start the world on a path to reducing the severity of climate change.