Climate change continues to pose a growing threat to Asia, where densely populated coastal megacities face the dual danger of rising sea levels and increased flooding. A recent report by Greenpeace East Asia highlights just how vulnerable the region is, warning that by 2030, more than 15 million people across seven major cities could be affected by ten-year floods—floods with a 1 in 10 chance of occurring in any given year.
While Jakarta’s sinking problem has long made international headlines, the report identifies Bangkok as the most at-risk city. An alarming 10.45 million residents could be exposed to flooding by 2030, with a staggering 96% of the city’s GDP in jeopardy—more than $500 billion (in purchasing power parity terms). Bangkok’s low elevation, urban sprawl, and compromised drainage infrastructure make it highly vulnerable to coastal and riverine flooding.
Next in line is Manila, where 1.54 million people are projected to be at risk. The Philippine capital could see 87% of its GDP—about $39.2 billion—disrupted due to rising seas and excessive land subsidence caused by unchecked groundwater extraction. Greenpeace warns that Manila is sinking by about 10 cm per year, echoing similar concerns raised in Jakarta.
Jakarta, which is already known as the fastest-sinking city in the world due to subsidence rates reaching 25 cm per year, could see 1.8 million people affected and a loss of 18% of GDP (approximately $68.2 billion). However, the threat is largely concentrated in the city’s north, with only 17% of Jakarta’s area expected to be flooded during a ten-year flood event. In response, Indonesia’s government has announced plans to shift the capital to East Kalimantan on Borneo Island—a move partly motivated by environmental concerns.
Further north, Taipei faces the second-highest economic exposure among East Asian cities. If sea levels rise as projected, 24% of its GDP could be lost, endangering neighborhoods near the Tamsui River and affecting roughly 430,000 people.
Tokyo, despite having sophisticated flood management infrastructure, is not immune. The report estimates that 830,000 people could be at risk and that flooding would impact 7% of the city’s GDP, or about $250 billion. Notably, only about 4% of the city’s land area would be inundated, but given Tokyo’s density, the human and economic toll could be considerable.
In Seoul, the risks appear lower in comparison, with just 130,000 people potentially affected and 1% of the GDP at risk. However, climate unpredictability and localized extreme weather events mean the situation could still evolve dramatically.
Meanwhile, Hong Kong—a city known for its vertical skyline and coastal proximity—would face minimal damage in relative terms. The report forecasts that just 90,000 residents and 0.4% of GDP could be impacted by a ten-year flood event, thanks in part to the city's elevation and urban planning.
It’s important to note that these projections do not account for the mitigating impact of flood defenses such as levees or sea walls, some of which are already in place or under construction in cities like Tokyo and Jakarta. The estimates are based on a worst-case scenario aligned with a 3–4°C rise in global temperatures by 2100, which many climate scientists still consider plausible under current global emission trends.
As Asia's coastal cities continue to expand, the urgency to address climate adaptation and resilience grows more pressing. From major infrastructure overhauls to urban relocation plans, the region faces tough decisions to safeguard its future against the advancing tide.
