Bangladesh could see 1.33 crore people displaced within the country by 2050 as rising sea levels, water scarcity and declining agricultural productivity intensify the effects of climate change, according to a new Asian Development Bank (ADB) report.
The country’s most climate-vulnerable coastal communities also face a double burden of flood exposure and poverty, with those at greatest risk often having the fewest resources to prepare for disasters, cope with their effects and recover, the report said.
The findings are contained in the Asia-Pacific Climate Report 2026: Coastal Risks on the Rise-Actions for a Resilient Future, released on Wednesday.
The report examines mounting threats to coastal communities, economies and infrastructure across Asia and the Pacific, and the urgent need for long-term investment in resilience.
It identifies Bangladesh, Myanmar and India as countries where poorer households are disproportionately exposed to coastal flooding.
Bangladesh’s vulnerability is compounded by the limited means available to many coastal households to withstand and recover from climate-related disasters.
The report highlights the unequal distribution of risk, warning that communities with the greatest exposure are often the least equipped to respond.
Bangladesh’s adaptation efforts
The report acknowledged measures Bangladesh has taken to reduce coastal risks, including its network of around 5,000 multipurpose cyclone shelters, early-warning systems and evacuation arrangements.
It also identified the Bangladesh Delta Plan 2100 as a framework for coordinating long-term investment and planning across water management, agriculture, livelihoods and ecosystems, with interventions tailored to vulnerable areas.
However, the scale of future climate risks makes sustained investment and stronger implementation essential, it said.
The report called for governments to incorporate adaptive planning into development decisions, strengthen institutions and governance, mobilise finance and maintain long-term commitment to resilience programmes.
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 2022-23. Despite the increase, the report said a substantial funding gap remained.
Public finance would continue to underpin coastal resilience, but governments would need to expand fiscal capacity and draw on additional public, private and concessional funding to support long-term projects.
For Bangladesh, the challenge is not only to protect coastal infrastructure and livelihoods but also to address the poverty and economic pressures that could force millions to move as climate conditions deteriorate.
Coastal losses could multiply
The report warned that coastal flood damage across Asia and the Pacific could rise more than sixfold by 2050 and nearly twentyfold by 2100 if governments fail to invest in adaptation.
Across 30 coastal economies, annual losses could increase from about $27 billion at present to between $172 billion and $199 billion by 2050, reaching $520 billion to $739 billion by 2100. The projections cover the region and do not provide a Bangladesh-specific estimate of future flood damage.
Keeping annual flood losses close to current levels would require an estimated $9 billion to $19 billion in coastal protection investment each year.
Such spending could prevent between $178 billion and $360 billion in damage annually, with potential benefits up to 20 times the investment, the report said.
“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.”
Coastal economies under growing pressure
The region’s coastlines generate around $7 trillion in annual economic output, supporting trade, ports, tourism and cultural heritage.
More than 400 million people, or over one in 10 residents of ADB’s developing member countries with coastlines, live within 10 kilometres of the sea.
Yet rising seas and increasingly severe hazards threaten both communities and economic activity.
The report warned that major coastal cities, including Bangkok, Jakarta, Kolkata and Mumbai, could face coastal floods that previously occurred once in a century every year by the end of this century.
Port disruptions could put an estimated $40 billion to $45 billion in economic activity at risk annually across the region.
Under a high-emissions scenario, annual flood damage in atoll nations could amount to 30 to 60 per cent of gross domestic product by 2100.
While larger economies could suffer the greatest losses in absolute terms, smaller island states could face especially severe economic consequences relative to their size.