In the high, dry mountains of the Indian Himalayas, indigenous communities facing severe water shortages have moved higher up the slopes, building their villages directly on top of ancient, rocky glaciers. Now, researchers have discovered that the underground ice sustaining these high-altitude settlements is rapidly thawing away. Scanning deep beneath the earth’s surface in the Spiti Valley, researchers showed that the permafrost within these ancient relict rock glaciers is degrading fast due to climate change, threatening the survival of the communities relying on it for fresh water.
The communities of Komic, known as the world’s highest motorable village, and Chicham, home to Asia’s highest bridge, sit in a cold, arid mountain desert. With traditional snow cover shrinking, residents have increasingly relied on springs and wetlands located on top of relict rock glaciers, which are landforms made of rocky debris that insulate a core of ancient ice. To understand what was happening beneath the surface of these vital water sources, scientists conducted the first-ever field-based geophysical survey of these inhabited rock glaciers. They used a technique called Electrical Resistivity Tomography, which involves injecting small electrical currents into the ground through metal stakes and measuring the resistance. Because solid ice strongly resists electricity while liquid water allows it to flow easily, the researchers were able to create detailed three-dimensional maps of the subsurface.
Instead of finding large blocks of solid permafrost, their scans revealed distinct lens-shaped pockets of highly saturated, muddy sediments. By taking samples and analysing the chemical fingerprints, or isotopes, of the water from local springs, the team confirmed a worrying reality. This vital liquid resource was mostly coming from the melting of ancient, underground paleo-ice rather than recent seasonal snowfall.
However, the researchers acknowledge that the electrical scanning method becomes less sharp at depths greater than forty metres, making it difficult to capture the complete three-dimensional picture of the deepest bedrock and complex geology. Furthermore, distinguishing between thawed permafrost and naturally wet soil can sometimes be tricky using electrical resistance alone. To build on these findings, the team notes that future studies will need to combine these electrical scans with physical boreholes, seismic surveys, and continuous year-round water sampling to get an even clearer view of the underground world.
Understanding the fragile state of these mountain water towers could be crucial for the residents who depend on them for water, as well as communities downstream. By mapping exactly where and how fast this ancient ice is disappearing, this research serves as a vital early warning system. It provides local governments and environmental planners with the critical data they need to develop climate-resilient water management strategies and disaster mitigation plans, ultimately helping safeguard the livelihoods and survival of vulnerable high-mountain communities worldwide.
