Asia-Pacific coastal flood losses could soar as ADB urges investment in protection

A new Asian Development Bank (ADB) report finds that investing in protection could deliver benefits worth up to 20 times the money spent.

Asia and the Pacific's coastlines generate $7 trillion in economic output each year, supporting ports, businesses and communities whose futures are increasingly threatened by rising seas and coastal flooding. A new Asian Development Bank (ADB) report finds that investing in protection could deliver benefits worth up to 20 times the money spent.

The Asia–Pacific Climate Report 2026: Coastal Risks on the Rise—Actions for a Resilient Future estimates that annual coastal flood damage across 30 economies could reach $172 billion to $199 billion by 2050 without adaptation, compared with approximately $27 billion today. By 2100, annual losses could climb to between $520 billion and $739 billion, putting homes, infrastructure and economic activity under growing pressure.

Coastal communities face a changing level of risk

More than 400 million people across the region live within 10 kilometres of the sea, representing more than one in 10 people in ADB's developing member economies with a coastline. These areas accommodate major ports and trade routes, alongside tourism destinations and heritage sites.

Larger economies could experience some of the biggest financial losses in absolute terms. For low-lying atoll nations, the damage could consume a much greater share of national income: under a high-emissions scenario, annual flood losses could reach 30% to 60% of gross domestic product by 2100.

The frequency of flooding could change dramatically in major cities. In Bangkok, Jakarta, Kolkata and Mumbai, coastal floods historically expected once every 100 years could occur annually by the end of the century.

Disruption to ports carries another substantial economic risk, with about $40 billion to $45 billion at stake each year across the region. The exposure extends beyond waterfront properties to the infrastructure through which goods reach businesses and markets.

Protection spending could prevent much larger losses

Keeping annual flood damage close to today's levels would require an estimated $9 billion to $19 billion a year in coastal protection, according to the report. Such investment could avoid $178 billion to $360 billion in flood damage annually.

Those estimates make a strong economic case for acting before losses escalate, particularly in places where public infrastructure and development decisions will shape exposure for decades.

Yevgeniy Zhukov, Director General of ADB's Climate Change and Sustainable Development Department, described coasts as an overlooked engine of regional growth facing retreat from rising seas and worsening hazards. He called for long-term solutions informed by risk, with the flexibility to adapt as conditions change.

The report's projections show the scale of the challenge: without adaptation, annual coastal flood damage could rise more than sixfold by 2050 and nearly twentyfold by 2100.

Funding and lasting public commitment will determine progress

ADB recommends four connected steps: bringing adaptive planning into development decisions, strengthening institutions and governance, mobilising finance, and sustaining implementation and local ownership.

For governments, this means connecting immediate protection measures with longer-term development objectives and allowing policies to evolve as risks change. Planning needs to account for future conditions as well as the hazards communities already face.

International adaptation finance flowing to coastal economies in Asia and the Pacific has increased, rising from about $5 billion in 2015 to an annual average of $11.4 billion in 2022–2023. A substantial financing gap remains.

Public funding provides the foundation for coastal resilience investment. Closing the gap will require governments to create more room in their budgets and draw on additional public, private and concessional financing for long-term protection.

The challenge reaches beyond securing money for individual projects. Sustained delivery, capable institutions and continued ownership will be needed to keep protection effective as coastlines, communities and climate risks change.