Robustness of norm-driven cooperation in the commons to environmental variability

Growing empirical evidence points to the importance of social norms for achieving sustainable use of common pool resources (CPR). Social norms can facilitate the cooperation and collective action needed to sustainably share a common resource. With global change, however, the social and environmental conditions under which cooperation has evolved and been maintained in the past may vary dramatically. Higher variability of resource availability and more frequent extreme events, for instance, will put additional pressure on cooperation, possibly triggering its collapse, with detrimental effects on the environment. In light of this, the potential impact of climate change on conflict has recently received considerable attention. Here we assess the robustness of norm-driven cooperation to changing resource availability in a stylised model of community harvesting from a shared resource. The model is a generalised representation of CPR extraction, which allows for social disapproval towards norm-violators. We use an agent-based model to assess the robustness of cooperative outcomes to variable resource flows. Our results indicate that both resource abundance and low resource variability can lead to its unsustainable use, while either scarcity or high variability in the resource have the potential to stabilize cooperation. These findings provide insights into possible effects of global change on self-governance of the commons. They also indicate that there is no simple answer to the question whether global change has the potential to destabilize cooperation in natural resource use, and lead to environmental degradation and possibly conflict.