IIT Indore-Led Study Finds 10% Decline in Snowmelt Flow from Gangotri Glacier (1980–2020)

A new study conducted by IIT Indore, the International Centre for Integrated Mountain Development (ICIMOD), Nepal, and U.S. researchers has revealed that the Gangotri Glacier system has lost about 10% of its snowmelt flow over the last four decades (1980–2020). The findings highlight the impact of climate variability and global warming on one of the most significant glaciers in the Himalayas, which feeds the Ganga River system.

Key Findings of the Gangotri Glacier Study (1980–2020)

The research analyzed four decades of hydro-climatic data and provided detailed insights into the changing dynamics of the glacier’s flow composition:

Flow Composition (Average of 40 years)

• Snowmelt: 64% (dominant contributor)

• Glacier melt: 21%

• Rainfall-runoff: 11%

• Base flow (groundwater): 4%

Decline in Snowmelt Contribution

• 1980–1990 → 73%

• 2000–2010 → 52% (sharp decline due to rising temperatures and reduced snowfall)

• 2010–2020 → 63% (partial recovery caused by colder, wetter winters)

This indicates that while snowmelt remains the primary contributor to the Gangotri system, its share has declined significantly, raising concerns about water security for millions of people dependent on the Ganga River.

Key Facts About Gangotri Glacier

• Location: Uttarkashi district, Uttarakhand (Central Himalaya, Garhwal region).

• Length: ~30 km, making it one of the largest Himalayan glaciers.

• River Origin: Source of the Bhagirathi River, the main headstream of the Ganga River.

• Feeder Glaciers: Sustained by tributary glaciers such as Raktavarn, Chaturangi, Kirti, and others.

Significance of the Study

The Gangotri Glacier is not only a sacred site in Hindu tradition but also a critical water source for millions across North India. Any decline in its snowmelt contribution poses serious risks, including:

• Reduced summer river flows, affecting irrigation and hydropower.

• Increased water stress in downstream states.

• Changes in flood and drought cycles due to altered hydrological balance.

Researchers emphasize that the big drop between 2000 and 2010 correlates with warmer and drier winters, while the partial recovery in 2010–2020 was linked to colder, wetter winters. This highlights the sensitivity of Himalayan glaciers to climate fluctuations.

Conclusion

The IIT Indore-led study underscores the urgent need for sustainable water management, glacier monitoring, and climate adaptation strategies in the Ganga basin. The Gangotri Glacier, as the lifeline of the Ganga, continues to face pressures from climate change, and protecting it is crucial for the environmental and economic security of India.

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