Collective action problems and conflicting obligations

Enormous harms, such as climate change, often occur as the result of large numbers of individuals acting separately. In collective action problems, an individual has so little chance of making a difference to these harms that changing their behavior has insignificant expected utility. Even so, it is intuitive that individuals in many collective action problems should not be parts of groups that cause these great harms. This paper gives an account of when we do and do not have obligations to change our behavior in collective action problems. It also addresses a question insufficiently explored in the literature on this topic: when obligations arising out of collective action problems conflict with other obligations, what should we do? The paper explains how to adjudicate conflicts involving two collective action problems and conflicts involving collective action problems and other sorts of obligations.