The environment comes later: when and how environmental considerations are included in transboundary water agreements

Until recently, most transboundary water agreements largely focused on utilization, frequently leading to environmental impacts. We examine under which circumstances are environmental considerations included in transboundary water agreements, how are they included and whether they address environmental effects of previous agreements. We analyse 75 treaties, many of which occur within (sub)basins with previously established water agreements. Human water stress, upstream large dams, OECD membership and previous water treaties (particularly those concerning utilization) are the most prevalent conditions where environmental degradation is considered. Our results also suggest that aridity incentivizes negotiating relationships to develop, thereby facilitating environmental water cooperation.