Himalayan Glacier Retreat: Bandarpunch Rate Falls from 25.5 to 20 Metres Annually

The news

The National Institute of Hydrology (NIH) has reported that the rate of retreat of Himalayan glaciers in key basins has slowed by more than five metres a year, according to a research report presented before the National Green Tribunal (NGT). The NGT bench, headed by Justice Prakash Shrivastava, received the report, which covers glacier retreat observations from 1962 to the present across the Bhagirathi and Yamuna catchments and the Bandarpunch region.

At Bandarpunch, the annual retreat rate fell from approximately 25.5 metres during 1960–1999 to about 20 metres over the past 25 years. In the Tons basin, the total glacier area declined by about 3.6 square kilometres, or roughly 5.4 per cent of its total glacier area, between 1962 and 2010. The Gangotri glacier retreated by approximately 819 metres from 1965 to 2006, and by about 223 ± 14 metres during 2006–2017. Between 2017 and 2023, its average retreat rate was about 21.1 metres per year, NIH said.

The report noted that the retreat is not confined to a single glacier system but is occurring across several basins in the Garhwal Himalayas, indicating wider hydrological and geomorphological changes. NIH told the tribunal that multiple scientific institutions, universities, and central and state government agencies are monitoring glacier changes in the Himalayan region.

What is the National Green Tribunal?

The National Green Tribunal was established on 18 October 2010 under the National Green Tribunal Act, 2010. It is a specialised judicial body equipped with expertise to handle environmental disputes involving multi-disciplinary issues. The tribunal is guided by principles of natural justice and is not bound by the procedure laid down under the Code of Civil Procedure, 1908. Its principal bench is in New Delhi, with other zonal benches across the country.

What do the retreat numbers mean?

The retreat distance, annual retreat rate and glacier area loss are separate measures and must not be interchanged. At Bandarpunch, the annual rate declined by about 5.5 metres between the two reported periods, but the glacier continued to retreat. Gangotri's measured retreat was approximately 819 metres in 1965–2006 and 223 ± 14 metres in 2006–2017. The slower rate does not indicate glacier recovery; it reflects a change in the pace of retreat over different observation periods.

What are the downstream risks?

Glacier melt contributes to river flows in the Ganga, Indus and Brahmaputra systems. A sustained retreat could initially increase summer flows but, over the long term, may reduce dry-season water availability, affecting drinking water and agriculture for an estimated 40 to 60 crore people in the northern plains, including Delhi and Kanpur. Retreat also leaves unstable glacial lakes that can burst and cause flash floods in Uttarakhand, Himachal Pradesh, Sikkim and Arunachal Pradesh, and weakens mountain slopes, raising the risk of landslides and damage to roads and bridges.