Maarg Manthan · Topic 20.18

Melting of Himalayan and Antarctic Glaciers and Its Climate Impact

Environment & Ecology › Protected Areas Lists and Recent Developments in Environment · Topic 20.18

Glaciers are large masses of ice that form from compacted snow and flow slowly under their own weight. The Hindu Kush Himalaya, often called the Third Pole, holds the largest store of ice outside the polar regions and feeds the great rivers Indus, Ganga and Brahmaputra, supporting hundreds of millions of people. A 2019 assessment by the International Centre for Integrated Mountain Development (ICIMOD) projected that even if global warming is held to 1.5 degrees Celsius, about a third of the glacier ice in the region could be lost by 2100, and much more under higher warming. Most Himalayan glaciers are retreating, though the Karakoram shows mixed behaviour. Causes include rising temperatures, black carbon and dust that darken the ice and increase melting, and changes in snowfall. Effects include more meltwater in the short run, followed by declining river flow later, the growth of glacial lakes and the risk of glacial lake outburst floods (GLOFs), as in Kedarnath in 2013, the Chamoli disaster in February 2021 and the South Lhonak lake flood in Sikkim in October 2023. Antarctica holds about 90 percent of the world's ice, and if the whole ice sheet melted, sea level would rise by around 58 metres, though this will take centuries; the West Antarctic ice sheet and glaciers such as Thwaites and Pine Island are losing ice, and ice shelf collapses, like Larsen B in 2002, release inland ice. Melting of ice sheets and glaciers is a major contributor to sea level rise, now about 4 millimetres a year by recent estimates. India has research stations Maitri and Bharati in Antarctica and Himadri in the Arctic. Hedge details: figures are updated by new studies, so check the latest IPCC and ICIMOD reports.

5 min read · UPSC Prelims · Environment & Ecology · Protected Areas Lists and Recent Developments in Environment

At a Glance

Third Pole Hindu Kush Himalaya
Rivers fed Indus, Ganga, Brahmaputra
GLOF events Kedarnath 2013, Chamoli 2021, Sikkim 2023
Antarctica About 90 percent of world ice
Sea level now About 4 mm a year
Exam link UPSC Prelims, Environment & Ecology: Protected Areas Lists and Recent Developments in Environment

Where Does It Fit?

This topic follows the farming topic and links to black carbon, climate impacts and rivers. It closes the physical climate topics before the final topics on river personhood and local water models. Previous topic: Permaculture vs Monoculture. Next topic: Ganga and Yamuna Rivers Accorded Legal Personhood Status.

What Is Happening to Himalayan Glaciers?

Aspect	Details
Region	Hindu Kush Himalaya, the Third Pole; feeds the Indus, Ganga and Brahmaputra
ICIMOD 2019	About one-third of ice could be lost by 2100 even at 1.5 degrees Celsius; much more under high warming
Trend	Most glaciers retreating; Karakoram shows mixed behaviour
Causes	Warming, black carbon, dust and changing snowfall
Water effect	More melt for some decades, then lower dry-season flow
Hazards	Glacial lake outburst floods, avalanches and landslides
Events	Kedarnath 2013, Chamoli 2021 and South Lhonak, Sikkim, 2023

What About Antarctica and Sea Level?

Ice volume: Antarctica holds about 90 percent of the world’s ice
Sea level potential: full melt would raise seas by around 58 metres over centuries
West Antarctica: less stable ice; Thwaites and Pine Island glaciers losing ice
Ice shelves: collapse such as Larsen B in 2002 speeds ice flow
Greenland: a larger present contributor to sea level rise
Sea level rise: about 4 mm a year recently, rising
Impact on India: risk to coastal cities, deltas and islands
Treaty: Antarctic Treaty of 1959 and Madrid Protocol of 1991

What Else Should You Remember?

Glacier types: valley, piedmont and ice caps
Indian Himalayan glaciers: several thousand glaciers by survey of GSI
Gangotri: source of the Bhagirathi; has retreated in recent decades
Siachen: one of the longest glaciers outside polar regions
Karakoram anomaly: some glaciers stable or advancing
Glacial lakes: formed behind moraine dams; unstable
GLOF: sudden release of water from a glacial lake
Kedarnath 2013: flood and landslides in Uttarakhand, linked with extreme rain and glacial lake burst
Chamoli 2021: rock and ice avalanche in the Rishiganga valley
South Lhonak 2023: lake outburst in Sikkim that damaged the Teesta III dam
Early warning: monitoring of lakes by satellite and sensors
Black carbon: darkens snow and ice
Albedo feedback: less ice, more absorption, more melt
Snowline: rises with warming
River flow: peak water effect then decline
Indus basin: relies most on glacier melt
Ganga basin: relies more on monsoon rain
Hydropower: projects face flood and sediment risks
IPCC SROCC: 2019 report on ocean and cryosphere
Antarctic stations: Dakshin Gangotri (1983), Maitri (1989) and Bharati (2012)
Arctic station: Himadri at Ny-Alesund, Svalbard, since 2008
Indian Antarctic Act: 2022 law
NCPOR: National Centre for Polar and Ocean Research, Goa
Policy: National Mission for Sustaining the Himalayan Ecosystem under NAPCC
Link to previous: see Permaculture vs Monoculture
Link to next: see Ganga and Yamuna Rivers Accorded Legal Personhood Status
Link to black carbon: see Black Carbon and Its Climate Impact
Caution: numbers change with new studies, so check IPCC and ICIMOD
Exam hint: remember Third Pole, GLOF events and Indian polar stations
Monitoring: Satellites, field stakes and the Geological Survey of India track mass balance of selected glaciers
Glacier retreat measure: Retreat is measured by the position of the snout, while mass balance measures gain or loss of ice
Downstream impact: Farming, drinking water and hydropower in the plains depend on predictable flow from the mountains
Adaptation: Options include early warning for lakes, avoiding settlement in hazard zones, small water storage and snow-based irrigation
Transboundary: The rivers flow through several countries, so glacier data sharing is relevant to treaties like the Indus Waters Treaty
Cryosphere: The term covers glaciers, ice sheets, sea ice, snow and permafrost

Why Does It Matter for the Exam?

Third Pole: Hindu Kush Himalaya
GLOF: 2013, 2021, 2023
Antarctica: Ice sheets, Maitri, Bharati
Current affairs link: Sikkim lake flood
Common errors: confusing Arctic and Antarctic stations

As an analytical point, glacier loss is slow but its hazards are sudden, and the effects on water, power and cities will cross borders. Adaptation needs lake monitoring, careful hydropower planning and cuts in warming and soot.

Why Is This Topic Important?

Cause Warming, soot
Hazard GLOF
Effect Water, sea level

What Came Next?

The next topic covers the legal personhood status accorded to the Ganga and Yamuna rivers. Next topic: Ganga and Yamuna Rivers Accorded Legal Personhood Status.

Key People and Terms

Cryosphere Frozen parts of Earth
GLOF Glacial lake outburst flood
Third Pole Himalayan ice region
Ice shelf Floating ice platform
Albedo Reflectivity
NCPOR Polar research centre

Exam Corner

Points to Remember

Third Pole = Hindu Kush Himalaya.
GLOFs: 2013, 2021, 2023.
Antarctic stations: Maitri, Bharati.
Arctic: Himadri.
Sea level: about 4 mm a year.

Do Not Confuse With

Maitri and Himadri Antarctic versus Arctic
Ice shelf and ice sheet Floating versus land-based
Glacier melt and sea ice melt Land ice adds to sea level, sea ice does not

Memory Hook

Third Pole melts, lakes burst; Maitri and Bharati watch the south.

Mains Angle

Questions ask for events, stations and effects. These points help.

Causes Warming, soot
Effects Water, hazards
Response Adapt

A Question You May Face

An original practice question, not a past paper question.

“Discuss the causes and consequences of melting of Himalayan and Antarctic glaciers. What measures can India take?”

How to Answer

Causes Warming.
Effects Water.
Hazards GLOF.
Response Adapt.

GS Relevance

Prelims: GLOF events, Antarctic facts, Indian stations. GS Paper 1 and 3: glaciers, climate and water security.

Frequently Asked Questions

Why are Himalayan glaciers important?

The Hindu Kush Himalaya, called the Third Pole, holds the largest ice store outside the polar regions and feeds the Indus, Ganga and Brahmaputra rivers. The meltwater supports drinking water, farming and hydropower for hundreds of millions of people downstream, so changes in ice affect water security across South Asia.

What is a glacial lake outburst flood?

A glacial lake outburst flood, or GLOF, is a sudden release of water from a lake formed by a melting glacier, when the moraine or ice dam gives way. Examples include the 2013 Kedarnath disaster in Uttarakhand, the 2021 Chamoli flood and the 2023 South Lhonak lake flood in Sikkim.

What does the ICIMOD report say about Himalayan ice?

A 2019 ICIMOD assessment of the Hindu Kush Himalaya found that, even if warming is held to 1.5 degrees Celsius, about a third of the glacier ice could be lost by 2100, and losses would be far greater with high emissions. Glacier retreat would change river flows and raise hazards.

How does Antarctic melting affect India?

Melting of Antarctic and Greenland ice adds to sea level rise, which threatens India's long coastline, deltas, ports and island territories through flooding, erosion and saltwater intrusion. Antarctic ice also affects ocean circulation and weather patterns, and India studies it through research stations such as Maitri and Bharati.

What are India's polar research stations?

India's Antarctic stations are Dakshin Gangotri (1983, now closed), Maitri (1989) and Bharati (2012). Its Arctic station is Himadri at Ny-Alesund, Svalbard, set up in 2008. The National Centre for Polar and Ocean Research in Goa coordinates the polar programme.

PYQ Practice — Statement Analysis

1 The Third Pole refers to the Hindu Kush Himalaya.

True

A large ice store.

2 Himadri is an Antarctic station.

False

It is in the Arctic.

3 Chamoli disaster occurred in 2021.