Beijing has long understood that China has a water-security problem that could pose an existential threat. In 2005, China’s minister for water resources reportedly ^[1] said, ‘To fight for every drop of water or die: that is the challenge facing China.’ Former premier Wen Jiabao observed ^[2] that water shortages threaten ‘the very survival of the Chinese nation’.

China has 20% of the world’s population ^[2] but only 7% of its fresh water ^[2]. And 80% of China’s water is in the south ^[3], whereas half of its population and two-thirds of its farmland ^[3] are in the north. While total water usage ^[4] in China increased by only 35% between 1980 and 2010, water usage in households increased elevenfold and in industrial sectors, threefold. But per capita available water in China amounts to only a quarter of the world average ^[5].

Climate change will also increase China’s vulnerability ^[4] to water scarcity. The average annual temperature in China has increased faster ^[6] than the global average and regional and seasonal patterns have changed significantly across the country, impacting negatively on the drier north of the country. More critically, climate change is causing glacial retreat in the Himalayas ^[7], which will result in a decrease in total water volume in major river systems in China.

The implications of these factors for China’s water security have become apparent. A three-year survey ^[8] of its river system completed by Beijing in 2013 indicated that the number of rivers in China had decreased by 28,000 from previous estimates. The flow of the Yellow River, which provides water to a significant proportion of China’s population, is a tenth of what it was 80 years ago ^[1]. In addition, groundwater aquifers, critically important to northern parts of China, are being depleted at a rate of 1 to 3 metres a year ^[1]. A 2015 study ^[9]of the country’s groundwater found that 80% was contaminated by toxic metals and other pollutants, rendering supply unfit for human consumption.

Given this context, Beijing’s announcement ^[10] late last year that it was moving ahead with plans to construct the world’s largest hydropower dam at Motuo on the Yarlung Tsangpo river ^[11] is likely as much about water security as it is about clean energy.

The new dam, one of at least eleven ^[12] to be constructed along the Yarlung Tsangpo, is considered ^[13] by some as a key element of Beijing’s plan to achieve net-zero emissions by 2060. When complete, it will generate up to 60 gigawatts of electricity. Nevertheless, China’s decision to proceed with the project now is curious for two reasons.

First, analysts ^[14] see such projects as unfeasible given the prohibitive costs associated with dam-building in the region and with the transmission network that would be required to get the electricity to distant population centres.

Second, existing installed hydropower already far outstrips demand ^[15] in China and Southeast Asia. Observers have noted ^[14] that Beijing is now tilting towards other forms of clean energy generation, such as wind and solar, instead of expensive signature hydro projects.

Beijing’s decision to proceed with the dam makes more sense in light of the likelihood of its being integrated into China’s South–North Water Transfer Project ^[16]. This project is designed to resolve the water shortage problem in China’s north by moving water through 1,500-kilometre-long canals.

The completed eastern and middle routes of the transfer project can transfer 20.9 billion cubic metres of water each year. In 2018, Beijing started exploring options for the controversial western route ^[17] of this project. This may result in tens of millions of cubic metres of water being diverted from the Yarlung Tsangpo and other transnational river systems in Tibet to the Yellow River. The project gained further impetus in early 2020, when Chinese Premier Li Keqiang called ^[18] for options.

The consequences of the new dam for downstream countries like India and Bangladesh could prove catastrophic. The Yarlung Tsangpo is a transnational river system that becomes the Brahmaputra River in India, which provides ^[19] 30% of the country’s water. The project could reduce water flows to India by 60%.

The environmental impacts in Tibet and downstream will be devastating. Peter Bosshard, the policy director of the International Rivers Organisation, noted ^[20] more than a decade ago, ‘A large dam on the Tibetan plateau would amount to a major, irreversible experiment with geo-engineering. Blocking the Yarlung Tsangpo could devastate the fragile ecosystem of the Tibetan plateau, and would withhold the river’s sediments from the fertile floodplains of Assam in north-east India, and Bangladesh.’

More recently, Brian Eyler of the Stimson Center said ^[12], ‘Upstream dams on the Brahmaputra impact downstream seasonal hydrological cycles which hold important cultural significance and impact local and national economic activities.’ Eyler drew comparisons with the impact of the 11 dams China constructed upstream from the Mekong Delta, noting that they ‘had a severe impact on hydrological cycles downstream, restricting the water flow at times of drought’.

Importantly, the Yarlung Tsangpo dam will also provide Beijing with significant leverage over its strategic rival India at a time when tensions between the two countries are worsening. China controls the sources ^[21] of 10 major rivers that flow through 11 countries and supply 1.6 billion people with water. As noted ^[22] by Dechen Palmo of the Tibet Policy Institute, ‘[T]he future of Asia’s water lies in China’s hands.’

Somewhat presciently, in 2010 the general manager of China Hydropower Engineering Consulting Group wrote ^[20] in favour of constructing a new dam at Motuo because it was a ‘great policy to protect our territory from Indian invasion’. China’s incursion into Ladakh in 2020 has also been seen as part of a broader Chinese strategy to build a strategic buffer ^[23] around key river systems originating in Tibet.

Given this broader context, the new mega-dam project on the Yarlung Tsangpo may be dressed up as a viable solution to China’s clean energy needs, but it is about much more than just its 2060 net-zero-emissions target. Given the likely downstream impacts, it might create almost as many environmental problems as it solves.