Climate change reshaping Gangotri glacier,source of Ganga: Study

Climate change is altering the very source of the Ganga River, with fresh research revealing how the Gangotri Glacier System (GGS) has been reshaped over the past four decades.
A study by scientists at IIT Indore has modelled Gangotri’s meltwater between 1980 and 2020, using the high-resolution Spatial Processes in Hydrology (SPHY) model. The model was calibrated with field discharge records, geodetic satellite-derived glacier mass balance data, and snow cover maps to assess how climate change has impacted the glacier-fed streamflow.
The findings show that snowmelt remains the dominant contributor to the glacier system, supplying 64% of the annual flow, followed by glacier melt (21%), rainfall-runoff (11%), and baseflow (4%). However, the composition has been shifting steadily.“After 1990, the discharge peak in GGS shifted from August to July, linked to reduced winter precipitation and earlier summer melting,” explained lead author Parul Vinze, a PhD scholar at the Glaci-Hydro-Climate Lab, IIT Indore. “Though snowmelt dominates, it has declined over time, while rainfall-runoff and baseflow have increased, subtly reshaping the basin’s hydrological balance.”The study, published after analysing 41 years of data, offers the most detailed perspective yet, improving upon earlier research that was limited by shorter records and coarser climate datasets.
“Accurate modelling, backed by field data, is key for predicting future water availability in the Himalaya,” stated Dr Mohd. Farooq Azam, supervisor of the study, Senior Intervention Manager-Cryosphere at ICIMOD, and Associate Professor at IIT Indore.While the Ganga River, at a basin-wide scale, has relatively less meltwater contribution compared to the Indus Basin, at higher elevations like the Gangotri Catchment, runoff is meltwater-dominated. The study warns that the observed changes in meltwater seasonality and runoff volume could severely impact hydropower generation and irrigation in the Himalayan region.

(Asstt.Editor)