Sonam Wangchuk's 'ice stupa' is saving Ladakh from a water crisis—Here's the brilliant science behind it

Ladakh’s long struggles with water scarcity have inspired one of the Himalayas' most inventive climate solutions: ‘an ice stupa’, a man-made frozen reservoir designed by engineer and activist Sonam Wangchuk. The idea developed around 2014 and 2015; it stores winter water as ice so it can be released gradually during the spring planting season, when farmers need it the most.

Water problems in Ladakh 

Ladakh sits in a cold, high-altitude desert where annual precipitation is usually below 100 millimetres, yet farming remains central to local life. Communities depend on water from melting glaciers to irrigate barley, apples and other crops, but that meltwater typically arrives in summer, after the spring sowing season has already begun. 

Climate change has made the challenge more severe with shrinking Himalayan glaciers and unpredictable rainfall and growing pressure on the potable water supply. That mismatch between when water is available and when crops need it has left farmers searching for a practical way to bridge the seasonal gap.

The ice stupa idea 

Wangchuk’s answer was to capture excess winter water that would otherwise go unused, freeze it in a place and shape it into a towering cone. The structure is called an ice stupa because it resembles the Buddhist stupas common across Ladakh while also serving a very practical purpose: acting as a slow-melting reservoir. 

“Water from a higher stream on the mountains is channelled down through the pipes to the village," the report explains, where the cold temperature causes it to freeze in layers and grow into a cone that can reach 20 metres or more. The shape matters because it exposes less ice to direct sunlight than a flat surface would, helping the stored water last for weeks instead of days.

From experiment to local tool 

The first tests were carried out with students from the school Wangchuck founded in Ladakh. Once the concept worked, nearby villages adopted it, and organisations contributed pipes and labour to help build more of the structures.

According to the report, the prototype stored about 150,000 liters of meltwater, while a later version held around 1.5 million liters, enough to irrigate thousands of seedlings planted by residents. Over time, more than a dozen artificial glaciers have been built in the region, collectively making tens of millions of litres of water available to communities.

Recognition and impact

The innovation has drawn international attention, and Wangchuk received a prestigious award in 2016 for the initiative, helping spread the idea to other mountainous regions facing similar water shortages. Its appeal lies in its simplicity: it is low-cost, energy-free and designed to work with the natural freeze-thaw cycle rather than against it.
In a region where water can define the rhythm of life, the ice stupa has become more than an engineering experiment. It is now a symbol of how local knowledge, scientific thinking and climate adaptation can come together to support vulnerable mountain communities.