UPSC Mains Answer Practice — GS 1: changing precipitation patterns in the Indus River system and increasing risk of Glacial Lake Outburst Floods (Week 164)

QUESTION 1

Climate change is increasingly altering the hydrological regime of river basins. Examine the geographical factors responsible for changing precipitation patterns in the Indus River system.

QUESTION 2

Retreating Himalayan glaciers are transforming the region’s physical geography by accelerating the formation and expansion of glacial lakes. Discuss the geographical factors responsible for the increasing risk of Glacial Lake Outburst Floods (GLOFs) in the Indian Himalayas.

QUESTION 1: Climate change is increasingly altering the hydrological regime of river basins. Examine the geographical factors responsible for changing precipitation patterns in the Indus River system.

Relevance: The topic examines how climate change is reshaping the physical geography of one of India’s major river basins, making it a strong GS1 Geography topic. It links changing precipitation patterns with river hydrology, groundwater, and regional geography while also offering interdisciplinary connections with environment and water resource management.

Note: This is not a model UPSC answer. It only provides you with a thought process which you may incorporate into the answers.

Introduction:

— The Indus River system, which originates in the Himalayas and Karakoram, is fed by a combination of monsoon rains, western disturbances, glacier and snowpack.

— Recent research reveals that precipitation in the eastern Indus sub-basins (Ravi, Beas, and Sutlej) has declined by approximately 20% since 1951, indicating a significant shift in the basin’s hydrological regime as a result of climate change.

Body:

You may incorporate some of the following points in your answer:

Factors responsible for changing precipitation patterns in the Indus River system

— Rising temperatures have accelerated the hydrological cycle, influencing moisture transport and precipitation distribution throughout the basin. Warming has contributed to decreased rainfall in the eastern Indus subbasins while also altering the time and intensity of precipitation episodes.

— The eastern rivers (Ravi, Beas, and Sutlej) rely heavily on the southwest monsoon. Increased monsoon variability, such as unpredictable rainfall and extended dry periods, has reduced average precipitation in certain catchment areas.

— The upper Indus basin receives a substantial amount of winter precipitation from Western Disturbances. Changes in their frequency, intensity, and course have influenced snowfall and rainfall patterns, altering seasonal water supply.

— Rising temperatures hasten glacier retreat and change the seasonal contribution of meltwater, affecting the basin’s hydrological equilibrium.

— Changes in air circulation influence how moisture interacts with mountain barriers, resulting in an unequal spatial distribution of rainfall across the basin.

— According to the study, precipitation in the eastern rivers has decreased more dramatically than in the western rivers. This reflects the different reliance of various subbasins on monsoon rainfall and winter precipitation, resulting in differential hydrological responses.

— Reduced rainfall has hampered natural groundwater recharging in the eastern basin. When combined with heavy groundwater extraction, this has increased water stress and altered the basin’s general hydrological regime.

Conclusion:

— Climate change, monsoon variability, western disturbances, Himalayan cryospheric changes, and complicated mountain terrain all combine to cause altering precipitation patterns in the Indus River system. These changes are modifying the basin’s physical landscape, emphasising the importance of climate-resilient river basin management, increased hydrological monitoring, and sustainable water resource planning for long-term water security.

(Sources: Rainfall in eastern river basins down 20% since 1951: Study on water availability in Indus river system, UPSC Issue at a Glance | Understanding Indian Monsoon: How it forms, what influences it and why it matters)

Points to Ponder

Physical characteristics of the Indus basin

Impact on agriculture, groundwater, reservoirs and settlements

Related Previous Year Question

Discuss the distribution and density of population in the Ganga River Basin with special reference to land, soil and water resources. (2025)

QUESTION 2: Retreating Himalayan glaciers are transforming the region’s physical geography by accelerating the formation and expansion of glacial lakes. Discuss the geographical factors responsible for the increasing risk of Glacial Lake Outburst Floods (GLOFs) in the Indian Himalayas.

Relevance: The topic connects climate change, the Himalayan cryosphere, geomorphology and disaster geography, making it a strong GS1 Physical Geography topic. It highlights how glacier retreat and glacial lake expansion are reshaping mountain landscapes and increasing hydro-geomorphic hazards such as GLOFs, an area of recurring importance in UPSC Mains.

Note: This is not a model UPSC answer. It only provides you with a thought process which you may incorporate into the answers.

Introduction:

— The Indian Himalayas are seeing fast glacier retreat as temperatures rise, resulting in the formation and growth of glacial lakes.

— While these lakes are vital freshwater reservoirs, their growing size and instability increase the possibility of Glacial Lake Outburst Floods (GLOFs), which are rapid releases of water caused by the breaking of natural dams built of moraine or ice. These events are transforming the physical geography of the Himalayas, increasing disaster risk.

Body:

You may incorporate some of the following points in your answer:

Geographical factors responsible for the increasing risk of GLOFs

— Rising temperatures are causing glaciers to recede at unprecedented rates. Meltwater accumulates in depressions created by melting glaciers, forming new glacial lakes and rapidly expanding existing ones.

— Unconsolidated moraines made up of loose boulders, sediments, and buried ice form the dams for the majority of Himalayan glacial lakes. These natural dams are physically unstable and prone to erosion, seepage, and catastrophic failure.

— The young fold mountains include steep slopes, unstable terrain, and active mass loss. Landslides, rockfalls, and slope failures can cause displacement waves to overtop or breach moraine dams.

— The Himalayas are in a tectonically active zone because to the continuous collision of the Indian and Eurasian plates. Earthquakes can collapse moraine dams and cause landslides into glacial lakes, resulting in GLOFs.

— Satellite data suggest that a sizable number of Himalayan glacier lakes have increased in recent decades, particularly in the eastern Himalaya. Larger lakes contain more water, increasing the catastrophic potential of any breach.

— Hydropower developments, roads, bridges, and expanded communities in narrow Himalayan valleys have made people and infrastructure more vulnerable to GLOFs.

Conclusion:

— The increasing frequency of GLOFs reflects the interplay of climate change, glacial retreat, and the Himalayas’ naturally vulnerable geomorphology. To protect vulnerable downstream towns, future hazards must be reduced through continuous satellite-based monitoring of glacier lakes, hazard zonation, strong early warning systems, climate-resilient infrastructure, and integrated mountain ecosystem management.

(Sources: How glacial lake expansion adds to the growing concerns about GLOFs, How ISRO used satellite remote-sensing to analyse glacial lakes in Himalayas)

Points to Ponder

Types of glacial lakes and moraine-dammed lakes

Impacts on settlements, infrastructure and mountain ecosystems

Related Previous Year Questions

What is the phenomenon of ‘Cloudbursts’? Explain. (2024)

How will the melting of Himalayan glaciers have a far-reaching impact on the water resources of India? (2020)

Previous Mains Answer Practice

UPSC Essentials: Mains answer practice — GS 3 (Week 164)

UPSC Essentials: Mains answer practice — GS 3 (Week 163)

UPSC Essentials: Mains answer practice — GS 2 (Week 164)

UPSC Essentials: Mains answer practice — GS 2 (Week 163)

UPSC Essentials: Mains answer practice — GS 1 (Week 163)

UPSC Essentials: Mains answer practice — GS 1 (Week 162)

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