How water can scale climate adaptation investment: Lessons from Southeast Asia

Climate risks are accelerating globally but they are not abstract. Many of these risks are increasingly felt through water: floods disrupting cities, droughts constraining industry and limited water resources driving water insecurity.

Water-related hazards already account for around 90% of global extreme weather events, making water the primary channel through which climate impacts are experienced.

However, the implementation of adaptation through water solutions lags behind what is needed, largely because financing at scale remains elusive, particularly in unlocking private-sector finance.

Against this backdrop, Adaptation through Water: Scaling Private Sector Finance for Climate Adaptation in Southeast Asia, the latest report from the Southeast Asia Partnership for Adaptation through Water (SEAPAW), identifies key enablers to help overcome this challenge.

Drawing on global experience and regional stakeholder insights, it explores how adaptation through water can be structured and scaled in Southeast Asia, with implications for global climate resilience.

By applying the adaptation through water lens at the regional level, this report helps stakeholders identify common risks, shared solutions and opportunities for cross-border collaboration, strengthening the case for scalable investment.

Water directly affects economies across sectors and underpins significant economic activity, making water-related risks more visible and measurable. This provides a tangible basis for embedding resilience into financial decision-making.

At the same time, the interconnected nature of water systems means investments in resilience can also generate cross-sector and system-wide benefits, beyond individual assets.

Yet many adaptation through water projects face the same financing challenges as other adaptation interventions because their benefits are spread across multiple actors and are difficult to convert into predictable cash flows.

As a result, scaling adaptation finance requires better project preparation, enabling market structures, policy alignment and institutional coordination to translate resilience needs into investable opportunities.

This finance gap is evident in Southeast Asia, where adaptation demand remains largely unmet, with up to 88% of needs unfunded annually.

The estimated investment needs of $12.9 billion for 2025-2030 far exceed available public funding of around $6.5 billion, leaving a financing gap of approximately $6.4 billion. This raises a critical question: what does it take to mobilize private capital for adaptation through water at scale?

The SEAPAW report, launched during Ecosperity Week 2026 in Singapore this May, seeks to answer this critical question.

Through global case studies and direct insights from investors, development finance institutions, corporates and SEAPAW members, a clear pattern emerges: projects become investable when four enablers are in place and supported by effective governance and coordination.

Private capital flows when there is a clear investment case. This can come from direct revenues (e.g. water services), increased land asset values or operational benefits such as reduced risk and secure supply chains.

Fragmentation is a major barrier. Aggregating projects across geographies or value chains through pooled funds or programmatic bundling creates scale, diversifies risk and improves bankability. This is particularly important given typical private investment ticket sizes of $2-20 million in the region.

Many projects face early-stage risks and long payback periods that do not align with commercial investor requirements. Structuring fit-for-purpose financing helps reallocate risk and crowd in private investment.

Investors need decision-useful metrics to assess risk and return. However, water-related outcomes are often not measured or verified in ways that can be used in financial decision-making. Robust MRV systems are therefore critical to linking resilience outcomes to financial value.

These enablers reinforce each other and are most effective when supported by strong governance and coordination mechanisms.

The SEAPAW report shows how these enablers can be applied in practice by focusing on two contrasting but highly relevant and vulnerable systems in Southeast Asia: source-to-sea watersheds and sustainable digital infrastructure.

These archetypes reflect different pathways for private sector participation.

Source-to-sea systems require coordination across geographies and stakeholders, from upstream agriculture and manufacturing to downstream urban infrastructure and ports.

In several Southeast Asia basins, water use already exceeds 40% of available supply, while climate hazards are increasing in frequency and intensity.

Scaling investment requires mechanisms that can align incentives, aggregate demand across stakeholders and translate distributed resilience benefits into bankable revenue streams.

Basin-level and transboundary coordination partnerships can play a key role in bridging governance gaps that no single actor or jurisdiction can close alone.

In contrast, sustainable digital infrastructure reflects a more concentrated, demand-driven model.

The rapid expansion of data centres and digital infrastructure is driving significant increases in water and energy demand, particularly in already water-stressed urban areas. This increases exposure to water scarcity, energy costs and regulatory pressure over local resource use.

At the same time, they create commercial incentives for them to invest in water and energy-efficient systems, reuse infrastructure and have a more reliable and diversified water supply.

In this context, risks and value are more directly linked to identifiable users, creating more tangible pathways to financing, particularly where large corporates can anchor demand through long-term commitments.

Across both systems, water is no longer just a sustainability issue but a core operational and financial risk. This is shifting the role of the private sector from a passive participant to an active driver of adaptation solutions.

Momentum is building and 2026 marks a critical year for turning intent into action. The global water cycle is increasingly out of balance, with direct consequences for economies, businesses and communities.

Ahead of the UN Water Conference in December, stakeholders are evaluating the urgency of the challenge and the pathways for action. The World Economic Forum’s Year of Water reflects a shift toward practical solutions, stronger partnerships and innovation.

The SEAPAW framework advances fit-for-purpose financing for resilience by showing how financial systems can support investments that generate long-term, system-wide benefits and how adaptation through water can become investable at scale.

The ability to mobilize private capital will be central to building water resilience in the years ahead.

SEAPAW is an initiative of the Singapore International Foundation, in collaboration with the World Economic Forum. It is the first regional multistakeholder platform that seeks to address the critical challenges of climate change, with a focus on water-related issues.

The authors would like to thank Alexandra Conroy for her valuable contributions and feedback.