A river is born high in the Tibetan Plateau, before snaking its way 3,000 miles south and emptying itself into the South China Sea. On its journey, it passes through six countries, sustaining their ecosystems and local economies, its fisheries providing a lifeline for 60 million people in its lower basin.
The Mekong changes names as it ventures southward through China, Myanmar, Laos, Thailand, Cambodia, and finally Vietnam. Its English title, from the Lao-Thai Me Khoong, or “Mother River,” emphasizes its life-giving nature. It has had a profound influence on the cultural traditions of the 95 ethnic groups who make their homes along its shores, and its basin is second in biodiversity only to the Amazon.
Water is the world’s most important resource, providing economic, agricultural and transportation benefits. This is especially true for the developing countries of Southeast Asia, who rely on rivers like the Mekong to spur economic growth and support local industries. But although the Mekong was the lifeblood of Southeast Asia long before modern-day borders were delimited, it has been at the root of acute political turmoil in recent years.
As the supply of water fit for irrigation and maintaining ecologies becomes increasingly scarce in the region, upstream countries that control vital transboundary resources, like China, wield an enormous amount of power. Although all of the Mekong’s riparian countries harness or plan to harness its waters for hydropower, extensive damming in China’s section has had the severest effects on downstream states.
The Mekong River is divided into upper and the lower basins. The upper basin falls mainly within China’s borders and its upstream location effectively allows for a chokehold on the river’s lower riparian states. China’s effects on the river are most evident in its extensive dam projects—hydropower is second only to coal as the country’s largest energy source.
This represents a larger shift by the government toward renewable energy in the wake of rapid environmental decline and social unrest due to air pollution in recent years. Luckily for China, authoritarian governments have a much easier time than democracies commissioning dams, which often cause mass displacement of populations and destruction of local ecosystems. China currently has seven dams completed in the upper basin, with another 20 set to be finished in the near future.
Chinese dam-builders are incentivized by the fact that the vast majority of the Mekong’s drop in elevation occurs within China’s borders in the southwestern province of Yunnan, creating a powerful downstream flow ideally suited for hydropower. However, this region is also famous for being one of China’s most biodiverse, and this damming comes at great harm to local ecosystems. Not surprisingly, hydropower projects in Yunnan have been met with fierce resistance, sometimes violent, by local environmental organizations.
But perhaps the gravest concern surrounding Chinese dams is their potential for an international crisis—studies in recent years have increasingly shown that China’s many dams are likely having serious effects on the countries in the lower basin who share the Mekong.
By changing water temperatures and altering sediment loads that are carried along the river, China’s dams pose a serious threat to fisheries downstream, the yields of which provide the major source of protein to the region’s inhabitants. More noticeable are the severe droughts and floods brought by a change in water flow caused by the dams. In March last year, China was approached by a desperate Vietnam asking that the Jinghong hydropower floodgates be opened to quench a downstream water shortage.
Mitigating a water crisis in the region is an issue the international community has sought to address for decades. In 1997, China was one of three countries that voted against the United Nations Watercourses Convention, an agreement establishing the non-navigational uses of transboundary waterways.
Since the 1960s, China’s per capita renewable internal freshwater resources have diminished by half thanks in no small part to explosive population growth and rapid industrialization; the country’s available water per person in 2017 is one-third of the world’s average. And this water crisis, compounded most recently by pollution, is likely a major factor in China’s close guarding of water resources within its boundaries.
Although Beijing has sought out less comprehensive regional initiatives with Southeast Asian countries to moderate the Mekong, these are difficult to enforce without the backing of the international community.
And unfortunately, the potential for crisis isn’t limited to the Mekong. China controls the “Water Towers of Asia”—the lofty sobriquet given to the Tibetan glacial plateau. The Mekong, Irrawaddy, Brahmaputra and the Salween all begin as trickles in these mountains before spilling across China’s borders to eager downstream riparian states. Getting first call on how these waterways are manipulated means that China poses a severe security risk to its neighbors.
China controls the life essence of eastern Asia: The towers within its domain provide water to 1.3 billion people. Up until now China has been compliant in releasing water when requested by downstream states, but the country’s water supplies are drying up. And as they do, assertions by recent scholars that 21st-century wars will be fought over water are becoming increasingly convincing.
Mr. Rechtschaffen is a graduate student at the University of Washington in China Studies, and a former editor at Sixth Tone.