A naturally or human-made system, where excluding individuals from benefiting is difficult and one person’s consumption reduces the availability of that resource for others, is centrally important for the understanding of many socioeconomic and environmental challenges. These resources are characterized by both subtractability, meaning that use by one individual diminishes the quantity available to others, and non-excludability, indicating the difficulty or cost associated with preventing individuals from accessing and utilizing the resource. Examples include fisheries, forests, irrigation systems, and the atmosphere.
Understanding the characteristics of these shared resources is vital because their mismanagement can lead to depletion, degradation, and conflict. Historically, a lack of effective governance has resulted in the “tragedy of the commons,” where individuals acting independently and rationally according to their self-interest deplete the resource, even when it is clear that doing so is not in anyone’s long-term interest. Recognizing the attributes of these shared assets allows for the design of appropriate management strategies to ensure their sustainability and equitable allocation.