Vietnam rethinks its flood strategy as climate change drives storms and devastation
HANOI, Vietnam (AP) — Vietnam is rethinking how it deals with flooding after a year of relentless storms that collapsed hillsides and left large parts of cities underwater.
From mapping high-risk areas to reimagining “sponge cities” that can absorb and release water naturally, Vietnam is investing billions to adapt to what experts call a new era of climate extremes. As part of a national blueprint until 2030, the government has pledged more than $6 billion to build early warning systems and get communities out of harm’s way.
In small towns like Vinh, in central Vietnam, these ideas are taking shape. Drainage networks are being expanded, flood basins are being dug, and river banks are being transformed into green spaces capable of absorbing and then draining away after heavy rains.
A wave of storms this year underscored the urgency of this work: Ragasa, Bualoi, Matmo – each blazed its own path of ruin. Record rainfall turned streets into rivers and caused slopes to slide, barely giving land time to recover between storms.
As Typhoon Kalmaegi strengthened this week on its path to Vietnam, scientists warned it may not be the last. It’s a glimpse into the country’s climate future: Warmer seas fuel storms that form faster, last longer and dump heavier rains, hitting poorer communities harder.
“Vietnam and its neighbors are on the front lines of climate change,” said Benjamin Horton, professor of earth sciences at City University of Hong Kong.
Climate change is reshaping Vietnam’s storm season
Scientists say the succession of storms hitting Vietnam is no accident but part of a broader change in the way storms behave on a warming planet. Vietnam typically faces about a dozen storms a year, but the one in 2025 is a “clear signal” of global warming, Horton said.
Ocean waters are now nearly a degree Celsius (33.8 degrees Fahrenheit) warmer than before the industrial age. Storms therefore carry more moisture.
The economic toll has been heavy for Vietnam, a developing country that wants to become rich by 2045. Floods regularly disrupt agriculture, fishing and factories – the backbone of its economy. State media estimates that extreme weather cost the country $1.4 billion in 2025.
Vietnam estimates it will need to spend between $55 billion and $92 billion this decade to manage and adapt to the impacts of climate change.
Vietnamese cities are not built to withstand climate shocks
About 18 million people, or nearly a fifth of Vietnam’s population, live in its two largest cities, Hanoi and Ho Chi Minh City. Both lie on river deltas that once served as natural buffers against flooding. But as concrete spread onto wetlands and farmland, cities lost their ability to absorb downpours.
Flooding in Hanoi in October persisted for almost a week in some neighborhoods. The city of more than 8 million people outgrew its infrastructure and its colonial-era drainage system broke down as streets turned into brown canals. Motorcycles sputtered through waist-deep water and Red River levees were tested.
Vegetable seller Dang Thuan’s house was flooded up to her knees, spoiling her stock. His neighborhood had several ponds, but they were filled in to build houses and roads. Now the water has nowhere to go.
“We can’t afford to move,” she said. “So every time it rains hard, we wait and hope. »
Between 1986 and 1996, a decade coinciding with the “Doi Moi” economic reforms that sparked a construction boom, Hanoi lost nearly two-thirds of the water bodies in its four main urban districts, according to a study by Kyoto University’s Center for Southeast Asian Studies.
Between 2015 and 2020, bodies of water covering the area of 285 football fields were lost, state media reported.
More than three-quarters of Hanoi’s land area – including much of its densely populated core – is at risk of flooding, according to a study in 2024. Flooding in the city cannot be solved by building more, said Hong Ngoc Nguyen, lead author of the study and an environmental engineer at Japanese consultancy Nippon Koei.
“We can’t control water,” she said, pointing to Singapore’s move away from concrete canals in favor of greener river banks that slow and retain stormwater instead of discharging it.
A global problem with lessons in nature
The idea of designing cities to “live with water” is gaining ground globally, including in Vietnam.
City officials and residents of Bangalore, India, are working to save the city’s remaining lakes, while Johannesburg, South Africa, is trying to restore the Jukskei River.
Recent flooding in Vietnam has sparked a broader debate about how cities should handle storms.
Former director of the National Institute of Urban and Rural Planning Ngo Trung Hai told the official Hanoi Times newspaper that the city must learn to live with heavy rains and adopt long-term strategies. European business associations have urged Vietnam’s financial capital, Ho Chi Minh City, to adopt a “sponge city” approach.
Real estate developers have been criticized in state media for inappropriate building practices, such as building on low-lying land or on roads not connected to storm sewer systems and treating bodies of water as “landscape features” rather than means of discharging stormwater.
Some of Vietnam’s biggest real estate developers have started to adapt. In the coastal tourist hub of Nha Trang, Sun Group is building a new township modeled after a “sponge city” with wetlands covering 60 hectares (148 acres), designed to store and reuse rainwater to reduce flooding and absorb heat.
City planners need to consider future climate risks, said Anna Beswick, who studies climate adaptation at the London School of Economics.
“If we plan based on past experience, we will not be resilient in the future,” she said.
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