Expansion of Glacial Lakes in the Himalayas Increases by Over 89% in 38 Years: ISRO

The results of the ISRO analysis are concerning, with experts warning that expanding glacial lakes due to warming can have cascading consequences in the lower regions. According to ISRO, satellite data archives spanning the past three to four decades provide valuable insights into changes occurring in glaciated environments.

ISRO’s report indicates that 601 glacial lakes, or 89 per cent, have expanded more than twice in size, with 10 lakes growing between 1.5 times and double their original size, while 65 lakes have expanded 1.5 times. The report also highlights that 314 lakes are located in the 4,000 to 5,000-meter range, and 296 lakes are above 5,000 meters elevation.

The study specifically points out the long-term changes in the Ghepang Ghat glacial lake in the Indus river basin, showing a 178 per cent increase in size from 36.49 to 101.30 hectares between 1989 and 2022, with an annual increase of about 1.96 hectares. ISRO emphasizes the value of satellite-derived long-term change analyses in understanding glacial lake dynamics for assessing environmental impacts, developing strategies for glacial lake outburst flood (GLOF) risk management, and climate change adaptation in glacial environments.

The ISRO report acknowledges the challenges faced in conducting the study due to the inaccessible and rugged terrain and highlights satellite remote sensing technology as an excellent tool for inventory and monitoring due to its wide coverage and revisit capability. The report also emphasizes the sensitivity of the Himalayan mountains to changes in the global climate, noting that glaciers in the region have been experiencing unprecedented rates of retreat and thinning, leading to the formation of new lakes and the enlargement of existing ones.

Recognizing the role of glacial lakes as freshwater sources for rivers in the Himalayan region, ISRO warns that dam failures can be triggered by various factors, including avalanches of ice or rock, extreme weather events, and other environmental factors.