Context: A recent study (IIT Indore, ICIMOD, US universities) reconstructed the hydrological discharge of the Gangotri Glacier System (GGS), showing shifts in meltwater trends due to climate change.
About Gangotri Glacier Decline:
- What it is?
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- The Gangotri Glacier System (GGS) is a major source of the Bhagirathi River, a key tributary of the Ganga.
- Comprises Gangotri, Chaturangi, Raktavaran, and Meru glaciers; ~549 km² area, ~48% glacierised.
- Trends:
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- Mean annual discharge (1980–2020): 28 ±1.9 m³/s.
- Contribution sources: Snowmelt (64%), Glacier melt (21%), Rainfall-runoff (11%), Base flow (4%).
- Peak discharge shift: From August (pre-1990) → July (post-1990) due to reduced winter snow and early summer melting.
- Snow cover decline: Reduced snowmelt despite rising temperatures.
- Rainfall-runoff & baseflow increasing, showing warming-driven hydrological changes.
- Implications:
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- Earlier peak discharge → risk of water scarcity in late summer/autumn for downstream communities.
- Greater flood vulnerability in July with intense monsoon rains.
UPSC Exam Relevance
- GS-I (Geography): Cryosphere, Himalaya geomorphology, monsoon interaction.
- GS-III (Environment): Climate change impact on glaciers, water resources, disaster management.
- Essay/Case Study use: Example of climate-induced hydrological shift in India.
- Ethics/GS-IV: Intergenerational equity in managing Himalayan ecosystems.
