Gangotri Glacier Decline

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?

• 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.

• 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:

• 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.

• 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:

• Earlier peak discharge → risk of water scarcity in late summer/autumn for downstream communities. Greater flood vulnerability in July with intense monsoon rains.

• 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.