Interacting collective action problems in the commons

We consider a setting where agents are subject to two types of collective action problems, any group user's individual extraction inducing an externality on others in the same group (intra-group problem), while aggregate extraction in one group induces an externality on each agent in other groups (intergroup problem). One illustrative example of such a setting corresponds to a case where a common-pool resource is jointly extracted in local areas, which are managed by separate groups of individuals extracting the resource in their respective location. The interplay between both types of externality is shown to affect the results obtained in classical models of common-pool resources. We show how the fundamentals affect the individual strategies and welfare compared to the benchmark commons problems. Finally, different initiatives (local cooperation, inter-area agreements) are analyzed to assess whether they may alleviate the problems, and to understand the conditions under which they do so.