The fragile Himalayan ecosystem is once again under scrutiny as a new study warns of escalating risks posed by glacial lake outburst floods (GLOFs) to hydropower projects in the region. This caution comes after the Indian government gave the green light to resume operations on the Teesta III hydropower project in Sikkim, which was severely damaged in a catastrophic GLOF event in October 2023.
The study underscores the growing threat of climate change-induced disasters in the Himalayas and raises concerns about the increasing number of dams and hydropower projects being built in highly vulnerable glacial zones.
The Catastrophic 2023 Glacial Outburst Flood
On 3 October 2023, a massive chunk of moraine material—about 14.7 million cubic meters— collapsed into South Lhonak Lake, triggering a devastating outburst flood. The impact generated a tsunami-like wave nearly 20 meters high, breaching the moraine and releasing 50 million cubic meters of water downstream.
The flood wreaked havoc along the 385-kilometer-long Teesta River valley, wiping out villages, infrastructure, and hydropower facilities, including the Teesta III project. Over 55 people lost their lives, and at least 70 more went missing. The disaster highlighted the extreme vulnerability of highaltitude infrastructure to climate-induced changes.
The Teesta Basin: A Hub of High-Risk Hydropower
The Teesta River basin in Sikkim has the highest density of hydropower projects in the Himalayan region, with 47 dams planned or under construction. The Teesta III project, initially built at a cost of ₹9,000 crore, was one of the largest in the region before it was devastated by the GLOF. Now, efforts to revive it raise fresh concerns about the long-term sustainability of hydropower in such hazard-prone regions.
According to the study, many hydropower projects in the Himalayas are located dangerously close to glacial lakes and unstable permafrost zones. The risk of sudden glacial collapses, like the one at South Lhonak Lake, is increasing due to rising temperatures and permafrost thawing.
A Growing Climate Crisis in the Himalayas
The 2023 disaster was not an isolated incident. Studies indicate that many Himalayan glacial lakes are expanding at an alarming rate due to rapid ice melt, increasing the likelihood of more GLOFs in the coming years. The instability of moraines—natural dams formed by glacial debris—has been documented well before the October 2023 event, with some shifting as much as 15 meters per year.
As the effects of climate change intensify, the likelihood of more extreme events in the Himalayas is increasing. The region’s delicate balance is being disrupted, with rising temperatures weakening the natural barriers that hold back glacial lakes. This makes hydropower projects particularly vulnerable
The Call for Safer Development and Early Warnings
In light of these findings, experts are calling for a reassessment of hydropower development strategies in the Himalayas. Some of the key recommendations include:
1. Stronger Risk Assessments: Future hydropower projects should undergo rigorous climate risk modeling before construction.
2. Early Warning Systems: Enhanced monitoring of glacial lakes and permafrost zones is critical for preventing disasters.
3. Reconsidering Dam Locations: Projects should be located at safer distances from glacial lakes to minimize potential damage.
4. International Cooperation: Given that the Himalayas span multiple countries, collaborative efforts are needed to manage climate risks effectively.
The recent study serves as a stark reminder that hydropower projects in the Himalayas are increasingly at risk from climate change-driven disasters. As the government moves forward with the revival of Teesta III and other similar projects, it must weigh the benefits of renewable energy against the dangers posed by a rapidly changing Himalayan landscape. Without stronger safeguards, these projects may become ticking time bombs rather than reliable sources of power.
As the world pushes for renewable energy, it is crucial to ensure that sustainability does not come at the cost of disaster-prone development. The Himalayas, often called the “Third Pole” due to their vast ice reserves, demand urgent attention to mitigate the mounting risks of glacial outburst floods.
