Published on: April 23, 2024

UNPRECEDENTED EXPANSION OF GLACIAL LAKES IN HIMALAYAS

UNPRECEDENTED EXPANSION OF GLACIAL LAKES IN HIMALAYAS

NEWS – Glacial lakes in Himalayas expanding at unprecedented rate, says ISRO

HIGHLIGHTS

  1. ISRO’s Findings:
    • ISRO’s satellite images spanning 40 years reveal significant expansion of glacial lakes in the catchments of Indian Himalayan river basins.
    • Glacial lakes are crucial freshwater sources but also pose flood threats downstream due to Glacial Lake Outburst Floods (GLOFs).
  2. Expansion Statistics:
    • Out of 2,431 glacial lakes larger than 10 hectares identified in 2016-17, 676 have notably expanded since 1984.
    • 130 of these expanding lakes are within India, situated in the Indus, Ganga, and Brahmaputra river basins.
  3. Types of Expanding Lakes:
    • Moraine-dammed lakes (water dammed by debris left by glaciers) account for 307 of the expanding lakes.
    • Others are water dammed in depressions formed by erosion, formed by ice, and due to other causes.
  4. Elevation-based Analysis:
    • 314 expanding lakes are located in the 4,000 to 5,000 m range, and 296 are above 5,000 m.

IMPLICATIONS AND RISK FACTORS:

  1. Glacier Retreat and Flood Risk:
    • Glaciers are retreating rapidly, leading to the formation and enlargement of glacial lakes.
    • Glacial Lake Outburst Floods (GLOFs) pose risks to downstream communities due to natural dam failures caused by avalanches or extreme weather events.
  2. Case Study – Ghepang Ghat Glacial Lake:
    • Example of Ghepang Ghat glacial lake in the Indus River Basin shows a 178% increase in size between 1989 and 2022.
    • This rapid expansion highlights the potential flood risk associated with glacial lake growth.

IMPORTANCE OF STUDY AND SATELLITE REMOTE SENSING:

  1. Understanding Glacier Retreat:
    • Long-term monitoring of glacial lakes aids in understanding glacier retreat rates and associated climate change impacts.
  2. Assessing Flood Risks:
    • Analysis helps in assessing the risks of Glacial Lake Outburst Floods (GLOFs) and developing mitigation strategies.
  3. Effective Remote Sensing Tool:
    • Isro emphasizes the effectiveness of satellite remote sensing in overcoming geographical limitations for studying glacial environments and associated risks.