In an era of apparent decline in international cooperation and rising crises, freshwater offers an area in which joint approaches remain absolutely essential—especially since water often transcends the boundaries of nation-states. 

Cooperation has long been the preferred approach in dealing with water resources shared with neighboring countries. Since the first—and so far, only—water war in 2550 B.C.E., states have favored cooperative action over conflict to manage, protect, or develop our planet’s 313 transboundary surface water basins and 468 transboundary aquifers.

Yet, while history has favored cooperation in managing transboundary waters, this trend is under threat. Increasing nationalism, a decline in treaty ratifications and joint institutions, and decreasing commitment to shared principles and norms, especially in environmental policy, signal a troubling shift towards unilateral action. This will have severe repercussions for ecosystems, people, and entire countries.

Collective Action Pays Off

This shift is even more surprising, as the benefits of water cooperation are plentiful. Improving a river’s water quality will be most successful if all polluters engage in limiting pollutants. Safe navigation is possible only if all countries agree to free navigation and implement adequate flow levels required for passage. 

These benefits extend beyond improved water management. Direct benefits emerge, including improved food and energy production. Indirect benefits include improved access to water for people and the economy, healthier ecosystems, and improved human health. Since water is an essential input for every economic sector and livelihood practice, these combined benefits provide a stable foundation for economic growth and socioeconomic development while also serving important cultural and spiritual needs.

Climate change’s impacts throughout the hydrologic cycle also mean that cooperation is increasingly crucial for ensuring resilience—as well as for maintaining local, subnational, and regional peace and stability. Cooperation thus ensures that the mutual benefits from shared water resources are greater than the sum of the benefits garnered through unilateral action.

Examples of the richness and diversity of such benefits abound: Cooperation between nations in the Danube River Basin, for instance, has cleaned up the formerly heavily polluted river through the construction or improvement of more than 900 wastewater treatment plants. Organic emissions have been reduced by 50%, and there has been a significant improvement in the Black Sea’s water quality, which was formerly suffering from severe pollution—much of it introduced via the Danube.

While challenges remain concerning the water quality of the Danube, the river is now safe to swim in, fish catches have increased, and tourism is thriving. In the Black Sea, biodiversity has recovered, and species have doubled since the 1980s. Cooperation also allows for newly emerging challenges to be addressed, such as new pollutants that threaten riparian ecosystems’ and people’s health .

Likewise, cooperation between Canada and the United States in the Columbia River Basin based on the 1964 Columbia River Treaty has ensured a control of downstream flows that provides flood protection benefits to US populations. Potential tragedies, such as the 1948 destruction of the entire city of Vanport, Oregon, can be averted. The treaty also offers stable conditions that generate economic benefits from commercial navigation to the transport of timber and provides a foundation for hydroelectricity generation that supplies electricity for 60% of the population in the Pacific Northwest and 90% of the region’s clean, renewable, and affordable energy.

The Senegal River Basin’s riparian states began a collaboration in the 1970s that has led to the joint development of several infrastructure schemes and the opportunity to create an additional 375,000 ha of irrigated area, improved navigation along the river that fuels trade and development, drinking water to the capital cities of Mauritania and Senegal, and 200 megawatts of hydropower potential. New projects, developed with financial support from external parties building on strong cooperation between riparian states, now provide further economic opportunities and address social and health concerns relating to water.

Stopping a Reversal of Flow

However, the benefits that cooperation on transboundary water can bring do not always seem to be apparent or obvious to all. Convincing decision-makers to cooperate in the current crisis climate is a challenge. The question of how to make the case for cooperation is becoming urgent to avoid the overall decline in multilateralism that the world is currently witnessing and prevent it from being increasingly reflected in states’ behavior over shared water resources.

The catastrophe could be immense. Over 50% of the world’s population resides in the river basins shared by about 150 different countries. This risk is also exacerbated by the fact that the benefits of shared water cooperation are still insufficiently understood and communicated—especially to decision-makers beyond the water sector.

Take the US government’s March 2025 decision to pause in treaty negotiations in the Columbia River Basin that have spanned the last several years. Delaying continuity in a long and successful history of beneficial cooperation in the basin risks not only environmental damage but also fundamental human and economic losses should hydropower provision decline or if flood protection afforded to the US fails. Subsequent indirect impacts on the overall economies and a legacy of close allyship between the states will also occur—and already are emerging as treaty negotiations become a tool in the current trade tensions.

The US pause in the Columbia River process is not an isolated incidence.  Guinea withdrew from the Organisation pour la Mise en Valeur du Fleuve Senegal in 2023—albeit for a brief period only; Egypt moved out of the Nile Basin Initiative in 2010; and Kyrgyzstan froze its membership in the International Fund for the Aral Sea in 2016. This trend in declining participation in joint institutions indicates a reduction in countries’ appreciation of water cooperation and the institutions that organize it, putting the benefits this institutionalized cooperation generates for ecosystems and people at risk.

These examples reflect a broader slowdown in treaty making and institution building over shared water resources. In recent years, fewer treaties have been adopted by states sharing watercourses than in previous decades. Only 10 such agreements have been signed since 2020, and only two basin organizations have been established—both in Southern Africa.

Moreover, the organizations that have been established do not receive consistent support from member states, thus creating uncertainty in their futures that turns them into zombie groups. The Authority for Lake Kivu and Ruzizi River (also known as ABAKIR) offers one example. It was established in 2014, yet its member countries never ratified the foundational legal instrument negotiated in the early 2010s. These nations also have not provided any financial or staffing resources to ABAKIR, leading to its slow death.

Recentering Water Cooperation on Benefits for All

So why are states engaging in less cooperation over their shared water resources—or even ceasing it entirely?

One factor is that the benefits of cooperation might be insufficiently clear, attributed, and/or valued, particularly by the political leaders who decide whether (and how) to engage in the process. This trend is compounded by a perception that the potential near-sighted wins from unilateral behavior and populist appeals will prove more directly beneficial to them and their immediate constituencies.

Putting the tangible positive outcomes of transboundary water cooperation at the center of attention is therefore essential, as well as creating a more concrete, attributable understanding of its direct and indirect benefits.

Measuring these benefits is a tricky business. The very few studies that have attempted to do so largely focus on (socio-)economic benefits only. They also often remain conceptual or focus on a single basin only.  An assessment of broader and sometimes even intangible benefits, such as ecosystem health for its own sake or the value of cultural water use, is challenging to create. They depend on numerous factors, many of which are beyond the immediate influence of water managers and policy-makers. Intensified academic research to understand the pathways from cooperative action to benefit generation and the equitable sharing of those benefits is, therefore, vitally important to inform decision-makers  

Charting a Course for Shared Prosperity

In a moment of growing geopolitical tensions and climate uncertainty, cooperation over shared water resources, resources that unite ecosystems, people, and countries, could be one of the most powerful tools to ensure a stable, secure, and sustainable future. In order to do so, we must recognize the broad benefits on offer—and make a concerted effort to measure and communicate them effectively, especially beyond the water sector. In doing so, we can safeguard water resources for generations to come—one collaborative action at a time.