Connecting water, health, and climate

Many of the pathways linking climate and health are mediated through water. In some cases, these pathways are straightforward. For example, greater variability in rainfall can reduce the availability of water, impacting health and undermining food and livelihood security. Other pathways are more complex and operate through cascading effects which can produce novel and unexpected outcomes. Droughts and floods can cause power shortages, which can force communities to use ad-hoc water storage onsite, enabling mosquitoes to breed and allowing diseases such as malaria and dengue to spread [4]. Bats that experience increased viral shedding at higher temperatures may feed on insects that, in turn, feed on microbiota in surface waters contaminated by antiviral residues, increasing the likelihood that emergent viral strains are resistant to current treatments [5,6]. These are interconnected processes that encompass interactions across complex systems that include environmental change, infrastructure resilience, governance, and social vulnerability.

Systems-based approaches that link these interconnections are not new. Frameworks such as Integrated Water Resources Management, One Health, and the more recent Planetary Health Approach all recognize the deep interconnections among human, ecological, social, and political systems. Each promotes collaborative, cross-sectoral strategies, policies, infrastructure, and institutions to anticipate, prevent, and respond to public health and environmental threats. But each also struggles with entrenched institutional and disciplinary silos, fragmented governance and narrowed funding structures, and the absence of frameworks that translate systems thinking into actionable policies. And, while water, health, and climate are found across these approaches, the explicit linkages between the three are often absent.

Prioritizing the water-health-climate nexus

To address this critical gap, we recommend specific steps to align incentives across sectors, support transdisciplinary collaboration, and build shared funding, data, and evaluation infrastructures around the nexus of water, health, and climate. By framing systems integration across these three - not only as a conceptual imperative but as an institutional and operational goal - we can better address the emergent challenges at the nexus of these complex systems.

A call to action

Climate change is a force-multiplier, exacerbating challenges at the water and health nexus. Achieving the vision of a sustainable and equitable future [13] requires coordinated action that addresses intersectoral risks and creates new and more effective strategies to improve and protect global health. Governments should lead the way by strengthening institutions and policies that promote intersectoral goals and approaches, provide funding across sector priorities, and adopt new goals and indicators that reflect and drive holistic responses at the local, national, and global levels. The scientific community can contribute by generating integrated evidence, developing shared metrics, and co-producing knowledge with practitioners and communities to inform joint decision-making. Civil society and community organizations must lead and support public engagement, ensure accountability, and translate national policies into locally relevant action.

While health considerations have long been embedded within the water supply sub-sector, the key challenge now lies in integrating this public health orientation with the broader water resources and climate communities to deliver holistic, systems-based responses.