The global perils of China’s new ‘superdam’ project

China has embarked on constructing the largest dam ever conceived on the Yarlung Zangbo River (better known as the Brahmaputra) in Tibet, just before it curves into India.

Beijing’s recent confirmation of the work marked the first open admission of a megaproject with sweeping hydrological, environmental and geopolitical implications.

One might have expected such a revelation to set off alarm bells worldwide. Instead, the reaction has been muted.

The project, once completed, will dwarf China’s Three Gorges Dam, currently the world’s largest. The Three Gorges was hailed as an engineering wonder but has since proved an environmental nightmare: eroding deltas, degrading water quality, triggering frequent landslides and causing seismic disturbances. The new Brahmaputra superdam is expected to generate nearly three times as much hydropower by harnessing the river’s sharp descent through the world’s deepest canyon. But its risks are immeasurably greater.

The superdam site lies in one of the world’s most seismically active regions, near a heavily militarized frontier where China claims India’s sprawling Arunachal Pradesh state as “South Tibet.” Giant dams are known to induce earthquakes, a phenomenon that scientists call reservoir-triggered seismicity.

Building the world’s largest dam on a fault line is not just reckless — it is a recipe for potential catastrophe. A structural failure or quake-induced collapse could unleash devastation across India’s northeast and Bangladesh, affecting tens of millions of people.

Beyond the seismic risks, the ecological costs could be staggering. The Brahmaputra, or Yarlung Zangbo, is no ordinary river. It is the world’s highest-altitude major river that originates in the glacial springs and wetlands of the Tibetan Plateau before flowing through India’s northeast and into Bangladesh. Along the way, it supports agriculture, fisheries and dense populations. Seasonal floods, far from being destructive alone, perform vital ecological functions: flushing out toxins, recharging groundwater and depositing nutrient-rich sediment that sustains farmland.

By trapping sediment and altering river flows, the dam would disrupt this natural rhythm. Bangladesh’s delta — already threatened by rising seas — could shrink further, losing the silt deposits that replenish its soil. Saltwater intrusion would worsen and catastrophic flooding could become more frequent. In India’s northeast, the agrarian economy would suffer due to fields being deprived of the natural fertilization cycles on which they depend.

For Beijing, however, water is not merely a resource — it is a strategic instrument. By positioning a megadam just before the river leaves Chinese-controlled Tibet, China gains the ability to manipulate downstream flows. It could withhold water during the dry season, unleash sudden surges during monsoons or gradually degrade ecosystems by capturing silt. Even without overtly weaponizing water, China’s unilateral control would introduce deep uncertainty for downstream communities, complicating long-term planning for agriculture, infrastructure and disaster management.

Such leverage carries profound geopolitical implications. India, already locked in a tense rivalry with China, would find itself at the mercy of Beijing’s hydraulic power. If bilateral tensions rise — as they did after China’s incursions into Indian Ladakh in 2020 — water could become an instrument of coercion. The symbolism is stark: At a time when control over oil once defined global power, control over freshwater flows is emerging as a comparable strategic asset in the 21st century.

This project also reflects a broader Chinese pattern. Since annexing Tibet in 1951, Beijing has emerged as the source of cross-border river flows to more countries than any other nation. It now boasts more large dams than the rest of the world combined. Its spree of construction has moved from internal rivers to international ones, with Tibet — Asia’s “water tower” — at the heart of this strategy. Eleven giant Chinese dams on the Mekong have already wreaked havoc on downstream nations like Thailand, Laos, Cambodia and Vietnam. Yet these lessons have not deterred Beijing.

Crucially, China rejects the notion of water sharing or joint management of shared rivers. It has no water-sharing treaty with any neighbor and it is not a party to the 1997 U.N. Watercourses Convention, the only global treaty governing shared rivers. That convention enshrines principles of equitable use, prior notification and harm prevention — principles that reflect customary international law. Beijing dismisses them, insisting instead on “indisputable sovereignty” over all waters within its borders.

The environmental stakes go well beyond South Asia. Tibet is warming nearly twice as fast as the global average. Glacial retreat, permafrost thaw and overdevelopment are already undermining ecosystems and accelerating biodiversity loss. With its massive elevation rising into the troposphere, the Tibetan Plateau profoundly influences Asian monsoons and climate, as well as the Northern Hemisphere’s wind circulation system. Any major alteration in its hydrology will reverberate beyond Asia’s weather system, with consequences felt worldwide.

China’s Brahmaputra project thus stands out as the riskiest megadam ever attempted — a potential “water bomb” in an ecologically fragile and politically volatile region. Its $168 billion price tag reflects not just an ambition to generate power but also a determination to secure leverage. For Beijing, hydropower is only part of the calculus; the greater prize is hydraulic dominance.

Despite this, global responses remain conspicuously absent. India’s measured objections highlight its lack of effective diplomatic tools. Other powers have preferred silence, wary of confronting Beijing. But passivity is shortsighted. The world ignored warnings about the Three Gorges Dam until its damage became undeniable. Repeating that mistake with a project of even greater scale in an even more fragile region would be perilous.

The international community cannot afford to avert its gaze. If left unchecked, China’s superdam will not just generate electricity — it will entrench Beijing’s hydro-hegemony.

This is not just another dam. It is a geopolitical and ecological time bomb — one that demands international action before its long fuse runs out.