Ecological collapse in the world’s largest mangrove forest is a preview of what’s to come

A river flows through the Sundarbans, the world’s largest mangrove forest, near Rampal, Bangladesh, in October 2022. (AP Photo/Al-emrun Garjon) Ecological collapse in the world’s largest mangrove forest is a preview of what’s to come Published: August 31, 2026 1.29pm EDT Share article Print article The first thing that struck us wasn’t the missing trees, but the missing water. In May 2026, we visited the Sundarbans, a mangrove forest in the delta where the Ganges, Brahmaputra and Meghna rivers meet in the Bay of Bengal. We went there expecting a story about the mangroves, the tangled, salt-tolerant forests that are supposed to be the last line of defence against cyclones and rising seas. What we found instead was a dry pond, cracked and empty, in a delta where water was never supposed to run out. A few months earlier it had held fish that fed families. Now it held nothing, and the family that once worked it had joined a self-help group, pooling savings from neighbours to try to make ends meet. That pond has stayed with us longer than any statistic about mangrove loss. It’s a small, specific failure, but one that’s occurring across an ecosystem where four million people depend on for food, income and shelter. The Sundarbans is often discussed as an ecological story: it is the world’s largest mangrove forest, a UNESCO World Heritage Site and a nursery for water and land creatures. Part of the Sundarbans mangrove forest, in Shyamnagar, Satkhira district, Bangladesh. (AP Photo/Mahmud Hossain Opu) That framing isn’t wrong, but it doesn’t tell the whole story. Embankments built to hold back tidal rivers are failing faster than communities can repair them, and the repairs themselves are increasingly makeshift: mud and bamboo patched in ahead of the monsoon rather than proper reinforcement. Saline water is pushing into land that used to grow rice, turning fields that once supported two harvests a year into ground that can barely manage one. Ponds that families relied on for freshwater aquaculture are turning brackish, and once they do, they don’t come back. The fish that survive in brackish water aren’t the ones that pay a family’s school fees or living costs; they’re smaller, less valuable and everyone I spoke with felt the difference. What people do about it is usually rather quiet and procedural: they form co-operatives, take on waged labour or send a child to a city they’d never planned on living in. This is what climate adaptation looks like when…