Why in news?
A recent study found that the Gangotri glacier in the Garhwal Himalayas has lost about 10 % of its snowmelt contribution to river flow over the past four decades. The research warned that climate change is altering hydrology in the Ganga basin.
About the glacier
The Gangotri glacier system is the largest in the Garhwal Himalayas, stretching roughly 30 kilometres and covering 143 square kilometres. It lies in Uttarkashi district of Uttarakhand within the Gangotri National Park. The glacier feeds the Bhagirathi river, a major tributary of the Ganga. Surrounding peaks include Shivling and Meru.
Findings of the study
- Declining snowmelt: Snowmelt accounts for about 64 % of the glacier’s contribution to river flow, down from 73 % in the early 1980s. Glacier melt contributes about 21 %, rainfall runoff 11 % and base flow 4 %.
- Shift in peak flow: Rising temperatures (about 0.5 °C increase) cause snow to melt earlier in the year. Peak river flow, which used to occur in August, is now shifting towards July.
- Increased rainfall runoff: More rainfall and less snow mean that a larger share of river water comes from rain. This makes flows more erratic and harder to predict.
Importance
- Water security: Millions of people downstream depend on meltwater from the Gangotri glacier for drinking, irrigation and hydropower.
- Hydropower and agriculture: Changes in flow affect hydroelectric projects and crop planning in the Indo‑Gangetic plains.
- Cultural significance: The glacier and the river Bhagirathi are sacred to Hindus. Pilgrims visit the source of the Ganga at Gomukh.
- Climate indicator: Monitoring glacier health provides insights into Himalayan climate change and helps inform adaptation strategies.