NEW DELHI – A new study from IIT Indore, along with collaborators from the U.S. and Nepal, has found that the Gangotri Glacier System (GGS), a primary source of the Ganga River, has lost 10% of its snowmelt flow over the past four decades due to rising temperatures caused by climate change. The research, which analyzed data from 1980-2020, reveals a critical shift in the glacier’s composition.
Snowmelt Declines, Rainfall Increases
Published in the Journal of the Indian Society of Remote Sensing, the study shows that while snowmelt remains the dominant source of water, its relative contribution has decreased from 73% in the 1980s to 63% in 2020. Conversely, the proportion of water from rainfall and base flow is increasing, a trend that scientists directly link to a 0.5°C rise in the average temperature within the Gangotri glacier system since 2001.
“This is clearly a signature impact of climate change,” explained Mohammed Farooq Aza, a supervisor of the study.
Peak Flow Shifts, Threatens Water Security
The research also found that the peak discharge of the glacier has shifted from August to July, a result of earlier snow melting. This trend has significant implications for hydropower generation, irrigation, and water security in the region, particularly for communities that rely on the glacier’s seasonal flow. The findings corroborate other studies that show Himalayan glaciers, on average, are losing thickness at a rate of 46 cm annually, a clear sign of ongoing degradation.