Lake- and land-terminating glaciers in the Padam Valley,Ladakh Himalaya: A comparative assessment of dynamics and mass changes

Abstract

Accelerated climate warming in the 21st century has intensified glacier retreat relative to the 20th century, establishing glacier shrinkage as a key indicator of climate change. This has led to the rapid expansion of glacial lakes, particularly in high-mountain regions. These lakes accelerate glacier mass loss by enhancing frontal ablation and promoting ice destabilization, increasing the risk of glacial lake outburst floods (GLOFs). To elucidate the dynamics of the proglacial lake (present at the terminus of the Padam Glacier) and its impacts on glacier behaviour, this study examines the Padam Glacier (lake-terminating) situated in the Padam Valley, Zanskar, Western Himalaya, and compares it with the neighbouring Nateo Nala (land-terminating) Glacier. In this study, satellite images of varying resolutions from the Landsat archive and Sentinel-2B, as well as digital elevation models (DEMs) from the Shuttle Radar Topographic Mission (SRTM) and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), covering the period from 1993 to 2022, were used. The lake-terminating glacier decreased in area by 11.6%, with a total retreat of 784 ± 51 m during 1993–2022. In comparison, the land-terminating glacier decreased in area by 5.3% and retreated to 324 ± 173 m during the same period. The proglacial lake increased in area from 0.35 to 0.57 km² (∼69%) between 1993 and 2022. Furthermore, the estimated surface ice velocity (SIV) of the glaciers has shown a significant reduction. The SIV of the lake-terminating glacier decelerated by 66%, ranging from 48 ± 6 to 16 ± 2 m a⁻¹ between 2001 and 2022. Similarly, the SIV of land-terminating glacier declined by 47%, ranging from 23 ± 6 to 12 ± 2 m a⁻¹ during the same period. In addition, the mass balance results indicate a negative mass balance of −0.22 ± 0.07 and −0.52 ± 0.07 m w.e.a⁻¹ for lake- and land-terminating glaciers, respectively. These findings highlight a distinct pattern in glacier dynamics and mass balance between lake- and land-terminating glaciers in the western Himalaya.