Abstract
Scarcity is often argued to be an important variable associated with explaining both conflict and cooperation over international freshwater. Yet it is the relationship between scarcity and cooperation that deserves additional scrutiny and, subsequently, rigorous empirical investigation. Building on existing literature, this article highlights the relationship between water scarcity and interstate cooperation. A model is introduced hypothesizing that cooperation is most likely to take place when the resource is neither abundant (when there is no real impetus for cooperation) nor highly scarce (when there is little of the resource to divide among the parties or the degradation too costly to manage). Rather, formal coordination in the form of an international water treaty is most likely to ensue at levels of moderate (or relative) scarcity. An inverted U-shaped curve, rather than a linear interaction, is consequently suggested for the relationship between water scarcity and cooperation. To illustrate this relationship, an analysis of variance (ANOVA) test is conducted using seventy-four country dyad observations, an associated scarcity index, and corresponding international treaty observations. Overall, results support the scarcity-cooperation assertion. Future research is needed to investigate this relationship in a more empirical and econometrically rigorous fashion.