Another meta-analysis of statistical studies on water wars shows a tiny risk of conflict and a much higher risk of cooperation

In this paper, we give the reader a comprehensive overview of the current state of research and provide an up-to-date review of statistical studies on conflict and cooperation around transboundary river basins. Extending previous work, we conduct a systematic assessment and open the debate for the subsequent presentation of an integrative conceptual framework of the water-security-conflict nexus, which is exemplarily applied to the cases of the Nile River Basin and the Syr Darya and Amu Darya river systems.

Cross-case studies exploring historical trends in transboundary water conflicts find that conflictive interactions are rare.4,27,28 Since 1948, supposedly 37 violent conflicts occurred, in which water played a major role. Thirty of these conflicts alone were fought between Israel and its neighbors. On the other hand, there were 1831 ‘water-related incidents’ in the past 50 years in TFDD, of which more than two thirds were of a cooperative nature.19 The IRCC database even lists 4797 events in the same time period but also concludes that most of the recorded events are cooperative.23 De Stefano and others27 find that between 1948 and 1999 and from 2000 until 2008, there have been moves toward less cooperative interactions between some countries. However, most negative events were rather moderate expressions of discord and hostility with little evidence of violent conflict.

Table 1 summarizes the large-N literature on water and transboundary conflict. Similar to the assessment of Johnson and others,26 we found strong dissent in this literature. Few studies investigate the links between reduced precipitation or hydropower development and violent intrastate conflict, and the results are quite ambiguous. By contrast, there is agreement among the four studies conducted that low water availability increases the risk for interstate disputes, especially between neighboring states. However, when exploring the relationship between adjacent countries with shared rivers, only five studies claim that a shared river increases the risk for violent conflicts between states, while 12 studies find no support for such a link. Furthermore, robust treaties and institutions can mitigate water-related conflict and facilitate cooperation even under hydrological stress.45,48,49

Despite evidence that water-related interactions are more often cooperative than conflictive, there has been a strong bias in water research on conflictive events. However, there are studies that find that signing of a water treaty positively influences future cooperation between the treaty partners e.g.,50 that water scarcity has a significant and positive relationship with the existence of river treaties,51 and that water scarcity enhances the incentives for riparians to cooperate.42 When considering nonlinear relationships, certain studies found a curvilinear relationship between the likelihood of cooperation and water scarcity.52–54 This suggests that transboundary water cooperation is most likely if water is neither extraordinarily scarce nor abundant. The projected amplification of hydro-climates55 thus has the potential to reduce international water cooperation.

In sum, research largely indicates that there is little evidence that shared rivers per se increase the risk of violent conflict between riparians. Water scarcity, by contrast, seems to make violent interactions between states, including those sharing river basins, more likely. However, this effect can be mitigated via well-designed institutions.56More importantly, water scarcity is empirically more likely to produce treaties and other forms of cooperation, while water-related interactions in general are more often cooperative than conflictive. There is no convergence on the conditions and pathways leading to either conflict or cooperation.