Although several dams already exist along the Yarlung Tsangpo, the difference this time lies in the scale of the project. It has already been nicknamed “The Mother of all Dams” — a title that captures both its immense size and its potential environmental cost [1].

The first consequence would concern the river’s natural flow and seasonal floods, which are vital to downstream aquatic ecosystems. Water quality would also deteriorate: upstream, sediments and oxygen-poor zones would accumulate, while downstream soils would be deprived of nutrients and coastal erosion would intensify. Local flora and fauna would be severely affected by variations in water level, oxygen, and temperature. Fragile habitats and endemic species might not survive [4].

These damages would add to the already ongoing processes. Today, 22% of the Yarlung Tsangpo basin is under significant human pressure [5], mainly due to agricultural expansion and changes in land use. The result is a substantial loss of native vegetation and biodiversity [6].

Finally, there is the seismic risk. In January 2025, a 6.8 magnitude earthquake damaged four reservoirs in Tibet, highlighting the fragility of dams built in mountainous areas with high tectonic activity [7].

Environmental concerns are accompanied by another major fear: that China could turn the Yarlung Tsangpo dam into an instrument of political leverage. Once again, this wouldn’t be unprecedented.

In 2021, Beijing reduced the Mekong River’s water flow by 50% — officially for power line maintenance. The river, which originates in China and flows through Cambodia, Laos, Myanmar, Thailand, and Vietnam, saw millions of people across Southeast Asia directly affected by that decision. Even earlier, in 2019, Chinese dams on the Mekong retained record levels of water, triggering an unprecedented drought in downstream regions, devastating ecosystems, and undermining both local economies and food security [1].

Tensions have also surfaced along the China–India border. In 2017, in the Indian state of Assam — the first to be crossed by the Brahmaputra — the river’s water suddenly turned black and muddy following a series of debris flows in the Chinese region. It became unfit for human consumption, with severe repercussions for local ecosystems [7]. Indian authorities accused Beijing of pollution linked to the excavation of an underground tunnel meant to divert part of the river’s course. China denied the accusations, dismissing even the existence of the project [8].

The dam on the Yarlung Tsangpo is not merely an unprecedented feat of engineering; it is a symbol of the new global era, where environment, energy, and geopolitics are increasingly intertwined.

On one hand, it represents a step forward for China toward carbon neutrality and energy self-sufficiency. On the other hand, it risks igniting regional tensions and causing irreversible damage to the ecosystems of the Himalayas and the Sundarbans of Bengal.

The future of the Brahmaputra does not concern only Beijing or New Delhi, but billions of living beings who depend on that river for their very survival.

Cover and preview image: Assorted flags in a Himalayan landscape. Photo by Abhishek Singh on Unsplash.

Figure 1: Lorenzo Barbieri, 2025. Physical cartography data from Google Satellite, Political cartography data from the QGIS data repository. Site location data from geohack.toolforge.org.