Relative Water Scarcity and Country Relations along Cross-Boundary Rivers: Evidence from the Aral Sea Basin

How do countries that share cross-border rivers respond to periods of abnormally low water availability? Existing research concerning water scarcity focuses on how cross-basin differences in absolute availability influence relations between countries. I argue that understanding whether countries react cooperatively or conflictually to within-basin shortages is important. I use the case of two major cross-boundary rivers in the Aral Sea basin of Central Asia to study the effects of within-basin relative scarcity. Employing original data on interactions among the Central Asian countries over the issue of water management, I find an association between, on the one hand, relative water scarcity and, on the other hand, an increased likelihood of both cooperative and conflictual interactions. By showing that relative scarcity affects when cooperative and conflictual events occur, my analysis highlights the fact that absolute scarcity is not the only type of water scarcity that influences international relations on cross-boundary rivers.