Scarcity and Cooperation along International Rivers: An Empirical Assessment of Bilateral Treaties

Water scarcity is popularly associated with inter-state conflict, yet the academic literature also touts scarcity as an important variable for understanding cooperation over international freshwater. Building on studies that consider the relationship between scarcity and hydro-political cooperation, this paper empirically investigates why water treaties are negotiated for some rivers and between some riparians, and not others. Rather than considering a linear relationship between scarcity and cooperation, this study hypothesizes a curvilinear relationship expecting agreements to emerge in situations where scarcity is moderate rather than very low or high. Additional variables considered for understanding treaty formation include level of governance among the riparian states, prevailing power dynamics along the river, overall inter-riparian relations (measured by trade, diplomatic ties, and militarized disputes), and the geographical configuration of the entire river. The hypothesized curvilinear relationship between water scarcity and cooperation finds significant support in the empirical analyses. Governance, diplomatic relations, and trade are likewise found to be salient in explaining the levels of cooperation. The geographical configuration of the river was significant in only part of the estimates, and the militarized disputes variable was found to be insignificant across all models. Finally, while results confirm that cooperation may not depend on power asymmetries within riparian dyads, as suggested by some theories, the paper does find support for the contention that more developed states are in a position to provide incentives, such as financial transfers, to less-developed states so as to facilitate an international agreement.

水资源短缺常被大众与国家间冲突挂钩，但学术文献亦将其视作理解国际淡水合作的重要变量。本研究立足于探讨水资源短缺与水政治合作（hydro-political cooperation）间关联的既有研究，实证探究为何部分河流、部分沿岸国（riparian）之间会谈判达成水条约，而其余则不会。本研究未预设短缺与合作间的线性关联，而是提出曲线关系假说：即水条约更易在水资源短缺程度中等的情境下形成，而非短缺程度极低或极高的场景。本研究纳入的其他用以解释条约缔结的变量包括：沿岸国治理水平、河流流域内的主导权力格局、沿岸国整体关系（通过贸易往来、外交联系及军事化争端进行衡量），以及整条河流的地理格局。实证分析结果为水资源短缺与合作间的曲线关联假说提供了显著支撑。治理水平、外交关系及贸易往来同样在解释合作程度方面表现出显著影响。河流地理格局仅在部分估算结果中具有统计显著性，而军事化争端变量在所有模型中均未表现出显著性。最后，尽管研究结果证实，正如部分理论所提出的那样，合作或许并不依赖沿岸国双边（riparian dyads）间的权力不对称，但本研究确实为另一论点提供了支撑：较发达国家可通过向欠发达国家提供财政转移支付等激励手段，助力国际水条约的达成。