Why is Glacial Lake Outburst Flood (GLOF) important for your UPSC exam

Key Takeaways:

1. GLOFs are disaster events caused by the abrupt discharge of h2o from glacial lakes — ample bodies of h2o that beryllium successful beforehand of, connected apical of, oregon beneath a melting glacier. As a glacier withdraws, it leaves down a slump that gets filled with meltwater, thereby forming a lake.

2. The much the glacier recedes, the bigger and much unsafe the water becomes. Such lakes are mostly dammed by unstable crystal oregon sediment composed of escaped stone and debris. In lawsuit the bound astir them breaks, immense amounts of h2o unreserved down the broadside of the mountains, which could origin flooding successful the downstream areas — this is referred to arsenic a GLOF event.

3. GLOFs tin beryllium triggered by assorted reasons, including glacial calving, wherever sizable crystal chunks detach from the glacier into the lake, inducing abrupt h2o displacement. Incidents specified arsenic avalanches oregon landslides tin besides interaction the stableness of the bound astir a glacial lake, starring to its failure, and the accelerated discharge of water.

4. GLOFs tin unleash ample volumes of water, sediment, and debris downstream with formidable unit and velocity. The floodwaters tin submerge valleys, obliterate infrastructure specified arsenic roads, bridges, and buildings, and effect successful important nonaccomplishment of beingness and livelihoods.

Reports highlighting the vulnerability astir GLOF

1. According to a study published by the Indian Space Research Organisation (ISRO) past year, 676 of the 2,431 glacial lakes larger than 10 hectares successful the Himalayas person notably expanded since 1984. Of these, 130 lakes are successful India, with 7 (7), fifty-eight (58), and sixty-five (65) successful the Ganga, Brahmaputra, and Indus stream basins, respectively.

2. The study noted that 601 lakes person much than doubled successful size, 10 person grown betwixt 1.5 to 2 times, and 65 lakes person expanded by 1.5 times. An elevation-based investigation reveals that 314 lakes are located betwixt 4,000 and 5,000 metres, and 296 lakes are supra 5,000 metres successful elevation.

3. The Ghepang Ghat glacial water successful the Indus River Basin, situated astatine an elevation of 4,068 metres successful Himachal Pradesh, has seen a 178 per cent summation successful size from 36.49 to 101.30 hectares betwixt 1989 and 2022.

4. According to a study, ‘Enhanced Glacial Lake Activity Threatens Numerous Communities and Infrastructure successful the Third Pole’, published successful the journal Nature successful 2023, since 1980, successful the Himalayan region, peculiarly successful southeastern Tibet and the China-Nepal borderline area, GLOFs person go much frequent.

5. “Approximately 6,353 sq km of onshore could beryllium astatine hazard from imaginable GLOFs, posing threats to 55,808 buildings, 105 hydropower projects, 194 sq km of farmland, 5,005 km of roads, and 4,038 bridges successful the region.”

6. Another analysis, ‘Glacial Lake Outburst Floods Threaten Millions Globally’, published successful the journal Nature successful February 2023, showed that astir 3 cardinal radical successful India and 2 cardinal successful Pakistan look the hazard of GLOFs.

While the fig and size of glacial lakes successful these areas (India and Pakistan) isn’t arsenic ample arsenic successful places similar the Pacific Northwest oregon Tibet, it’s that highly ample colonisation and the information that they are highly susceptible that mean Pakistan and India person immoderate of the highest GLOF information globally.

Tom Robinson, co-author of the study

7. According to the State of the Cryosphere 2024 – Lost Ice, Global Damage, a study released astatine the United Nations Climate Change Conference successful Baku, Azerbaijan (November 11-22, 2024), stated that owed to rising temperatures, grounds glacier melting has occurred successful 2023 globally, including successful Asia and the Indian Himalayan Region is among the regions straight affected by these changes.

BEYOND THE NUGGET: Situation successful Uttarakhand

1. Recently, the Uttarakhand government has constituted teams of experts to measure the hazard posed by 5 perchance hazardous glacial lakes successful the region. These lakes are prone to Glacial Lake Outburst Floods (GLOFs), the benignant of events that person resulted successful respective disasters successful the Himalayan states successful caller years.

2. Uttarakhand has witnessed 2 large GLOF events successful the past fewer years. The archetypal took spot successful June 2013, which affected ample parts of the authorities — Kedarnath vale was the worst hit, wherever thousands of radical died. The 2nd occurred successful February 2021, erstwhile Chamoli territory was deed by flash floods owed to the bursting of a glacier lake.

3. These glacial lakes person been categorised into three hazard levels: ‘A’, ‘B’, and ‘C’. Five highly delicate glacial lakes autumn into the ‘A’ category. These see Vasudhara Tal successful the Dhauliganga basin successful Chamoli district, and 4 lakes successful Pithoragarh territory — Maban Lake successful Lassar Yangti Valley, Pyungru Lake successful the Darma basin, an unclassified water successful the Darma basin, and different unclassified water successful Kuthi Yangti Valley.

4. The rising surface temperatures could worsen the concern successful Uttarakhand. The state’s yearly mean maximum somesthesia whitethorn summation by 1.6-1.9 grade Celsius betwixt 2021-2050, according to a 2021 study, ‘Locked Houses, Fallow Lands: Climate Change and Migration successful Uttarakhand, India’, carried retired by the Germany-based Potsdam Institute for Climate Research (PIK) and The Energy and Resources Institute (TERI) successful New Delhi. This could exacerbate the hazard of GLOFs successful the state.

(Source: Govt to motorboat survey to measure vulnerability of glacial lakes aft monsoon, Why Uttarakhand govt wants to measure the hazard of Glacial Lake Outburst Floods, 14 months aft glacial water flood, Sikkim’s Teesta dam gets situation motion for rebuild without nationalist hearing, Hindu Kush Himalaya faces accrued risks amid grounds glacier melting)

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