ADB Warns Asia-Pacific Coastal Flood Damages Could Reach $739 Billion by 2100
ADB warns of rising coastal flood risks across Asia and the Pacific as climate adaptation needs grow.
Annual coastal flood damages across Asia and the Pacific could rise more than sixfold by 2050 and nearly twentyfold by 2100 without effective adaptation measures, according to a new report released by the Asian Development Bank (ADB) on Wednesday.
The Asia–Pacific Climate Report 2026: Coastal Risks on the Rise—Actions for a Resilient Future estimates that annual flood damages across 30 coastal economies could reach $172 billion to $199 billion by 2050. By 2100, losses could climb to $520 billion to $739 billion, compared with approximately $27 billion today.
According to the ADB, the region’s coastlines generate around $7 trillion in annual economic output. However, rising sea levels and increasingly severe coastal hazards threaten communities, infrastructure and economic activity.
Coastal Resilience Could Deliver Major Economic Benefits
The report highlights the economic case for investing in coastal protection. It estimates that annual investments of $9 billion to $19 billion could help keep flood damages close to current levels.
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Such spending could prevent an estimated $178 billion to $360 billion in flood damages each year, with the benefits of coastal resilience investments potentially reaching 20 times their cost.
“Coasts are the overlooked engine-room of Asia and the Pacific’s growth but are retreating in the face of rising seas and escalating hazards,” said Yevgeniy Zhukov, Director General of ADB’s Climate Change and Sustainable Development Department.
“We are at a turning point and must act now with long-term, adaptive, and risk-informed solutions to create resilient coasts that keep people safe and economies running,” he added.
Millions Face Growing Exposure to Coastal Hazards
More than 400 million people across the ADB’s developing member economies with coastlines live within 10 kilometres of the sea. This represents more than one in 10 residents of these economies, according to the report.
Coastal areas support major ports, international trade, tourism and heritage sites. Damage to these areas could therefore affect livelihoods, supply chains and economic growth well beyond the immediate flood zones.
Larger economies could experience the highest financial losses in absolute terms. However, smaller atoll nations could face a much heavier burden relative to the size of their economies.
Under a high-emissions scenario, annual flood damages in some atoll nations could reach 30% to 60% of gross domestic product (GDP) by 2100.
The report also warns that coastal floods historically expected once every 100 years could occur annually by the end of the century in major cities, including Bangkok, Jakarta, Kolkata and Mumbai.
Port Disruptions Pose a Major Economic Risk
The ADB estimates that disruptions to ports across the region place approximately $40 billion to $45 billion at risk each year.
Ports are vital to regional and global supply chains. Flood-related closures and infrastructure damage could interrupt trade, increase costs and undermine business activity.
The report therefore calls for governments to incorporate climate risks into infrastructure development and long-term economic planning.
ADB Calls for Stronger Planning and Financing
To strengthen coastal resilience, the ADB recommends four priorities:
Integrate adaptive planning: Connect immediate protective measures with long-term development goals and update plans as risks change.
Strengthen institutions and governance: Improve coordination, planning and accountability.
Mobilise financing: Expand public investment and attract private and concessional funding.
Sustain implementation: Maintain long-term commitment and clear ownership of resilience projects.
International adaptation finance for coastal economies in Asia and the Pacific roughly doubled from around $5 billion in 2015 to an annual average of $11.4 billion in 2022–2023.
Despite this increase, the report says a substantial financing gap remains. Public finance will continue to underpin coastal resilience, but governments must also expand fiscal capacity and mobilise additional funding from private investors and development partners.
The ADB emphasises that early action and flexible planning can help countries reduce future losses while protecting communities, infrastructure and economic opportunities.
Founded in 1966, the Asian Development Bank is a multilateral development bank that supports sustainable, inclusive and resilient growth across Asia and the Pacific. It works with member countries and development partners to address regional challenges, finance infrastructure and protect the environment. The institution is owned by 69 members, including 50 from the region.
