'Asia's Water Tower' Is Becoming Less Predictable, Tibetan Plateau Study Finds

A new study measuring "entropy" - the level of chaos or disorder - in the Tibetan Plateau's soil moisture system says the region often called "Asia's water tower" is heading towards a more unpredictable and unstable future. The study, led by physicist Chen Xiaosong of the School of Systems Science at Beijing Normal University, was published on August 21 in Nature Communications, just days before a catastrophic flash flood struck the Nepal-China border, killing hundreds of people.

Chen's team examined the plateau's soil moisture from 2000 to 2024, a system closely linked to water and climate patterns affecting nearly 2 billion people across South and East Asia. Over that period, soil moisture across the plateau increased significantly, with about 57.5% of the region showing significant wetting and only 8.1% showing significant drying. Soil-moisture entropy declined over the same period, meaning the system became more organised, with the decline accelerating after about 2018 as the plateau grew wetter.

But the researchers project that trend will reverse. "From 2025 to 2100, entropy starts to rise and the system becomes more disordered," said the study's first author, Xie Yiran. The projected rise is accompanied by declining soil moisture, weaker hydrological buffering and stronger contrasts between the plateau's western and southwestern regions. The model ensemble showed a significant breakpoint around 2052, after which the dominant soil-moisture pattern declined at more than twice its earlier rate.

The system is also influenced by El Nino and La Nina, opposite phases of a Pacific climate cycle called the El Nino-Southern Oscillation (ENSO), with the plateau's soil-moisture entropy lagging ENSO's own entropy by about six months. Chen said that from now to the end of the century, "the increase of soil water and the intensification of glacier melting [in the Tibetan Plateau] will constantly trigger such geological disasters," adding that "India will definitely be affected, but the specific impacts still require further analysis and research."

The authors describe their finding as a heightened risk of instability in a complex system, rather than proof of an inevitable tipping point.