Reframing Water Security Under Climate Change: Evidence,Uncertainties,and Priorities for Adaptation and SDG 6 Progress

Abstract

Climate change is reshaping freshwater availability, quality, and distribution, posing major challenges to water security. Increasing hydroclimatic variability, extreme events, glacier retreat, salinity intrusion, and shifting precipitation are disrupting water systems globally, with disproportionate impacts on vulnerable populations. Despite growing research, key gaps remain in understanding compound risks, cross-sectoral interactions, and adaptation effectiveness under uncertainty. This editorial synthesizes current evidence on climate impacts on water security, focusing on hydrological variability, infrastructure resilience, governance, and inequality. It highlights gaps in integrated assessment, data systems, and science–policy translation. Priority research areas include improved climate–water modeling, nature-based solutions, adaptive governance, and scalable innovations in storage and reuse. Aligned with Sustainable Development Goal 6 (SDG 6), this Special Collection calls for interdisciplinary contributions that advance both theory and practice toward climate-resilient water management.

1. Introduction

Water security has emerged as one of the defining challenges of the 21st century, increasingly shaped by the accelerating impacts of climate change on hydrological systems and water-dependent societies. Climate-induced alterations in precipitation, temperature, and evapotranspiration are intensifying water scarcity, exacerbating flood risks, and undermining the reliability of water supply systems worldwide. Beyond amplifying existing pressures, climate change is introducing deep uncertainty, challenging conventional assumptions of predictability that have historically underpinned water management and planning. In this context, water security must be understood as a non-stationary system, in which historical hydrological patterns are no longer reliable guides for future conditions. We argue that water security is no longer defined solely by resource availability, but increasingly by variability, uncertainty, and inequality, requiring a fundamental rethinking of how risks are assessed and managed.

At the global scale, the implications are profound. The frequency and intensity of droughts are increasing, including in regions historically considered water-abundant (Alberts & Özerol, 2025). Concurrently, cryospheric decline—particularly glacier retreat and snowpack loss—threatens long-term freshwater availability for populations dependent on mountain “water towers”. Coastal systems are also experiencing rising salinity intrusion driven by sea-level rise and altered freshwater flows (Debnath & Alamdari, 2026). These trends reflect a broader shift toward more variable and less predictable hydrological regimes.

These climate-driven changes interact with socio-economic pressures such as population growth, urbanization, and land-use change, producing complex and interconnected risks. Water security has therefore evolved into a multi-dimensional concept encompassing availability, access, quality, reliability, governance, and equity. Climate change is intensifying inequalities in water access, disproportionately affecting vulnerable populations and regions with limited infrastructure and institutional capacity. At the same time, interdependencies across water, energy, and food systems further complicate adaptation responses (Shi et al., 2026). The urgency of these challenges is reflected in the global development agenda, particularly Sustainable Development Goal 6 (SDG 6). However, progress remains uneven, with climate change increasingly recognized as a central limiting factor in achieving its targets. The growing convergence between SDG 6 and climate action (SDG 13) underscores the need for integrated strategies that enhance both water security and climate resilience.

Despite significant advances, current research remains fragmented across disciplinary boundaries, limiting its capacity to capture the full complexity of climate–water interactions. Critical gaps persist in understanding compound risks, evaluating adaptation effectiveness under non-stationary conditions, and translating scientific knowledge into policy and practice. Data scarcity—particularly in low- and middle-income regions—further constrains monitoring, modeling, and decision-making (Alao et al., 2025). To address these challenges, this editorial synthesizes current knowledge and advances a structured research agenda for climate-resilient water security, linking observed impacts, persistent knowledge gaps, and priority areas for innovation. By framing water security as a dynamic and interconnected system under deep uncertainty, this Special Collection seeks to catalyze interdisciplinary research and actionable solutions aligned with SDG 6.

To structure this evolving understanding, we propose a conceptual framework for climate-resilient water security that links four interdependent dimensions (Figure 1): climate drivers, system pressures, governance and infrastructure responses, and water security outcomes. Climate drivers—including rising temperatures, shifting precipitation patterns, and increased frequency of extreme events—generate system pressures such as hydrological variability, water scarcity, flooding, and water quality degradation. These pressures interact with existing socio-economic conditions and are mediated by the capacity of built infrastructure, ecological systems, and governance arrangements to respond and adapt. The effectiveness of these responses determines water security outcomes across key dimensions, including availability, access, quality, reliability, and equity. Crucially, these outcomes are not static; they feed back into system conditions by influencing vulnerability, adaptive capacity, and long-term resilience. Under conditions of climate non-stationarity, these interactions become increasingly dynamic and uncertain, requiring flexible, integrated, and adaptive management approaches. This framework provides a unifying structure for interpreting climate impacts, diagnosing knowledge gaps, and identifying priority directions for research and policy.

Figure 1.

Conceptual framework for climate-resilient water security

2. Climate Change Impacts on Water Security

Within the conceptual framework outlined in Figure 1, climate change acts as a primary driver of system pressures, directly influencing both the quantity and quality of water resources. For example, it shifts precipitation, rising temperatures, and extreme events disrupt hydrological systems and increase vulnerability (Granata & Di Nunno, 2026). Also, hydrological extremes are intensifying, with droughts becoming longer and more severe, while floods are more unpredictable, often occurring in the same regions and creating compound risks (Alao et al., 2025; Shi et al., 2026). Finally, water quality is deteriorating due to rising temperatures and altered runoff which increase eutrophication, algal blooms, and pollutant transport, thereby affecting ecosystems and treatment systems. Impacts are unevenly distributed because vulnerable populations face compounded risks from limited infrastructure, governance constraints, socio-economic conditions, and sectoral competition, highlighting the need for integrated and cross-sectional water management approaches (Shi et al., 2026). Additionally, competition across sectors—agriculture, industry, energy—further intensifies vulnerability, highlighting the need for integrated, cross-sectoral planning.

3. Critical Knowledge Gaps

Despite considerable progress in understanding the impacts of climate change on water security, critical knowledge gaps persist, limiting the development and implementation of effective adaptation strategies. These gaps are not isolated; rather, they reflect systemic limitations across scientific, technical, and governance domains. To clarify priorities and support a more coherent research agenda, we classify these gaps into three interrelated categories: structural, systemic, and translational.

Structural Gaps: Data, Models, and Observational Capacity. Structural gaps relate to limitations in the foundational tools and datasets required to understand and manage water systems. Access to high-quality, spatially and temporally resolved data remains uneven, particularly in low- and middle-income regions where monitoring networks are sparse and fragmented (Bandala, 2025). These limitations hinder the development of predictive models, early warning systems, and real-time adaptive management approaches (Alao et al., 2025). In addition, many hydrological and climate models remain insufficiently equipped to capture groundwater dynamics, sediment processes, and water storage variability under changing climatic conditions. Data inconsistencies and limited interoperability further constrain cross-regional analysis and knowledge transfer.

Systemic Gaps: Complexity, Interactions, and Compound Risks. Systemic gaps result from the limited ability of current research to fully understand the complexity of interactions within and across water systems. Much of the existing literature remains fragmented across disciplinary boundaries; for example, hydrological, socio-economic, and governance aspects are often addressed separately (Granata & Di Nunno, 2026), which hinders the development of integrated frameworks that can effectively address coupled human–natural systems.

Moreover, climate-related hazards rarely occur in isolation. Droughts, floods, heatwaves, and water quality degradation can interact in non-linear ways, producing compound and cascading risks across sectors and regions. However, understanding of these interactions—including their frequency, intensity, and propagation pathways—remains limited (Ogwu & Izah, 2026). Without accounting for such dynamics, adaptation strategies risk underestimating system-wide vulnerabilities.

Translational Gaps: From Knowledge to Action. Translational gaps reflect the persistent disconnect between scientific knowledge and its application in policy and practice. While numerous adaptation strategies—including infrastructure upgrades, water reuse technologies, and nature-based solutions—have been proposed, their real-world implementation is often constrained by governance limitations, financial barriers, and institutional fragmentation.

There is also limited evidence on the long-term effectiveness of adaptation measures under non-stationary climate conditions. Many interventions are evaluated using historical data that may no longer reflect current or future realities, creating uncertainty about their robustness and scalability across diverse socio-economic and environmental contexts. Addressing translational gaps requires governance systems that can accommodate uncertainty, support adaptive management, and foster multi-stakeholder collaboration. Strengthening these mechanisms is essential to ensure that advances in scientific understanding led to tangible improvements in water security. Together, these structural, systemic, and translational gaps highlight that advancing water security under climate change requires not only improved knowledge, but better integration across disciplines and stronger pathways from science to implementation.

4. Avenues for Future Research and Innovation

Building on the identified knowledge gaps and the conceptual framework proposed in this editorial, the following priority directions represent key areas for advancing climate-resilient water security:

• Integrated modeling combining climate, hydrology, socio-economic factors, and infrastructure to assess risks under uncertainty.

• Nature-based and hybrid solutions, integrating ecological and engineered approaches for resilience.

• Adaptive governance, emphasizing flexibility, participation, and cross-scale coordination.

• Data and monitoring systems, including remote sensing and real-time tools for early warning.

• Transdisciplinary research co-producing knowledge with stakeholders to enhance implementation.

These priorities align closely with the Grand Challenges outlined in this Special Collection and provide a foundation for future interdisciplinary research and innovation.

5. Conclusions and Call to Action

Addressing climate-driven water challenges requires integrated, adaptive, and participatory approaches. Governance must evolve toward flexibility, multi-stakeholder collaboration, and iterative learning (Parsons et al., 2025). Hybrid solutions combining nature-based and engineered systems should be prioritized.

Investments in data infrastructure are essential, particularly in data-scarce regions (Alao et al., 2025). Bridging science and practice requires collaborative platforms linking researchers, policymakers, and practitioners (Bandala et al., 2026). Cross-sectoral planning across water, energy, and food systems is critical to reduce trade-offs and enhance resilience (Shi et al., 2026).

Climate change has emerged as the central driver of water insecurity, reshaping hydrological systems through increasing variability, uncertainty, and inequality. Persistent gaps in integrated modeling, data, and governance limit effective responses.

Tackling these challenges requires interdisciplinary, solution-oriented approaches aligned with SDG 6. This Special Collection invites contributions that advance understanding and practical solutions for climate-resilient water management. The conceptual framework and typology of knowledge gaps presented in this editorial provide a structured basis for advancing both research and practice in this domain.

6. Call to Action

The accelerating impacts of climate change on water systems demand a step change in how research, policy, and practice are conceptualized and implemented. Incremental advances are no longer sufficient. There is an urgent need to redefine water security within a non-stationary and uncertainty-dominated context, where traditional assumptions of predictability and stability no longer hold.

This Special Collection on Climate Change Adaptation for Water Security is conceived as a platform to shape the next generation of research and practice in this field. We invite contributions that not only advance understanding, but also challenge prevailing paradigms, bridge disciplinary boundaries, and provide actionable insights for decision-making.

We particularly encourage submissions that address the following interrelated Grand Challenges:

1. Understanding and modeling non-stationary water systems. Advancing integrated frameworks that capture the dynamic interactions among climate drivers, hydrological processes, infrastructure, and socio-economic systems under deep uncertainty.

2. Anticipating compound and cascading water risks. Moving beyond single-hazard approaches to quantify and manage interacting extremes—such as droughts, floods, and water quality degradation—and their cross-sectoral impacts.

3. Closing the data-to-decision gap. Developing innovative approaches to overcome data scarcity, improve real-time monitoring, and translate complex datasets into actionable intelligence for adaptive management.

4. Designing and evaluating adaptation under uncertainty. Providing robust evidence on the performance, scalability, and equity implications of nature-based, engineered, and hybrid solutions across diverse contexts.

5. Enabling adaptive and inclusive governance. Identifying institutional arrangements, policy instruments, and participatory approaches that support flexible, equitable, and multi-level water management in a changing climate.

We argue that climate change is no longer an external stressor to water systems, but the central limiting factor in achieving sustainable and equitable water security, including progress toward SDG 6. Addressing this challenge requires research that is not only scientifically rigorous, but also solution-oriented, inclusive, and implementation-ready.

By contributing to this Special Collection, authors will help define a forward-looking research agenda, inform global and local adaptation strategies, and accelerate the transition toward climate-resilient water management. We particularly encourage submissions that foreground equity, scalability, and real-world impact, ensuring that advances in knowledge translate into tangible benefits for the most vulnerable populations.