Editorial: Lessons from Nepal's tragedy

To climate denialists and somnambulists in India, the catastrophic flash floods in Nepal on Wednesday (August 26) must sound like a thunderclap of reality.

A glacial collapse that was mistaken for an earthquake on the border with Tibet generated an avalanche that blocked the Lhende Khola river and then gave way to the massive buildup of water.

The release of pent-up water, boulders and mud surged down the river, smashing every natural and man-made structure on the banks. The latest reports put the human toll at 165, while thousands are missing, many of them foreign nationals, including 300 from India.

This catastrophe brings to the fore the threat of glacial lake outburst floods (GLOFs) in South Asia. The region has over 25,000 glacial lakes, and accelerated warming is leading to their rapid expansion. At the same time, development activity in the lower Himalayan valleys is making mountainsides vulnerable to disintegration.

Moreover, development debris is being deposited in the riverbeds, which narrows the channel and encourages settlements closer to the river. This creates a cocktail of conditions that can lead to the kind of disaster Nepal is having today.

No less than 7,000 glacial lakes are said to be vulnerable to flash floods.

India’s Himalayan states, and also those like Bihar and Assam that are downstream of rivers, face great risk from such events. Over 50 million people live within the danger zone in Jammu & Kashmir, Ladakh, Himachal Pradesh, Uttarakhand, and Sikkim, where hundreds of hydroelectric dams and border roads have been built with little regard to environmental concerns.

The frequent disasters resulting from cloudbursts and landslides are symptoms of this. The government’s skewed priorities were glaringly exposed by the GLOF in the South Lhonak lake in Sikkim in 2023, when the Teesta-III dam was washed away, claiming 90 lives.

The GLOF threat to Himachal Pradesh has dramatically increased in recent decades with the government aggressively building hydropower projects and roads in mountain terrain without giving environmental issues due attention.

Studies have reported that the number of glacial lakes relevant to the state has increased from 107 in 1990 to 669 in 2024. Out of the 94 larger glacial lakes, 88 have been flagged as potentially susceptible to bursting.

Most of them are held back by loose rock debris that can give way to a buildup of water either due to sudden cloudbursts and/or accelerating snowmelt.

Himachal has suffered due to GLOFs in the past. In June 2005, a glacial lake formed on the Pareechu river across the border in Tibet and its natural barriers gave way, resulting in flash floods in the Sutlej river basin.

A massive wall of water rushed down to the Kinnaur valley, destroying bridges and highways and causing massive damage to the Nathpa Jhakri hydropower station.

The Nepal catastrophe should serve as a wake-up call to development policymakers in South Asia.

Every aspect of this tragedy needs to be studied in the minutest detail. The immediate priority is to expand the National Disaster Management Authority’s early warning systems and hazard mapping in the Himalayan states.

Alongside, there is a need to fund community preparedness initiatives in the entire region. However, the main lesson from Nepal remains: there is peril ahead if development does not go hand in hand with the environment.