Recent satellite images from the Indian Space Research Organisation (ISRO) have raised global concerns about the rapid expansion of glacial lakes in the Himalayan region over the past 3-4 decades.
According to ISRO’s data, over 600 glacial lakes, representing 89% of the total lakes in the Himalayas, have more than doubled in size since the 1980s. These expanding lakes pose a significant risk of Glacial Lake Outburst Floods (GLOFs), which can have devastating effects on communities living downstream.
ISRO’s satellite imagery, covering Indian Himalayan river basins from 1984 to 2023, shows that 676 glacial lakes have expanded noticeably since 1984. Of these, 130 lakes are located within India, with 65, 7, and 58 lakes situated in the Indus, Ganga, and Brahmaputra River basins, respectively.
Melting glaciers due to climate change is leading to the formation and enlargement of glacial lakes in the Himalayan region. These lakes serve as crucial freshwater sources for Himalayan rivers but also pose significant risks due to GLOFs.
GLOFs occur when large volumes of meltwater are released from glacial lakes due to the failure of natural dams, such as moraines or ice. These failures can be triggered by avalanches, extreme weather events, or other environmental factors.
Monitoring and studying glacial lakes in the Himalayas is challenging due to the inaccessible and rugged terrain. However, satellite remote sensing technology offers a comprehensive solution for inventory and monitoring, as it provides wide coverage and revisit capability.
Elevation-based analysis reveals that 314 lakes are located between 4,000 and 5,000 meters, and 296 lakes are above 5,000 meters. The lakes are categorized into Moraine-dammed, Ice-dammed, Erosion, and other types. Among the expanding lakes, Moraine-dammed lakes are the most common, followed by Erosion, other, and Ice-dammed lakes.
Long-term change analyses based on satellite data are crucial for understanding glacial lake dynamics, assessing GLOF risks, and gaining insights into the impacts of climate change. These analyses provide valuable information for developing strategies for GLOF risk management and climate change adaptation in glacial environments.
