Impact of Climate Variability on the Feeding Glaciers of Potentially Dangerous Glacial Lakes in the Jhelum Basin of Kashmir Himalaya, India

Abstract

Global climate change has resulted in the widespread melting of glaciers. The formation of new lakes and the expansion of existing lakes has now become a common phenomenon in high mountainous regions due to the continuous meltwater supply from these retreating glaciers. Studies in the Himalayan region have reported the retreat of glaciers and the rapid expansion of glacial lakes due to increasing temperatures and a declining trend in precipitation. This study analyzed the impact of climate variability (temperature and precipitation) on the feeding glaciers of potentially dangerous glacial lakes (PDGLs) in the Jhelum basin of the northwestern Himalayas. Multitemporal satellite data (Landsat series) were utilized to extract the glacier and glacial lake boundaries for the years 1980 and 2020. In addition, Google Earth imagery, LISS-IV, and Sentinnel-2A data were used for cross-checking and validating the glacial lakes. Both automated [normalized difference water index (NDWI) and normalized difference snow index (NDSI)] and semiautomated (manual interpretation) techniques were used to identify and map the glaciers and glacial lakes in the study region. To analyze the impact of climate change on the feeding glaciers of PDGLs, Indian Meteorological Department (IMD) station data were utilized. The results show that PDGLs in the study area have experienced significant growth, whereas the area of the feeding glaciers has decreased remarkably. The total area of the PDGLs in 1980 was 6.50 km2, which has increased to 8.47 km2, i.e., a growth of 1.97 km2 (30%). However, the area of feeding glaciers has decreased from 19.38 to 11.58 km2, a deglaciation of about 7.8 km2 (40.24%). The forecast model predicted that, by the year 2030 the decadal growth in the total glacial lake area will be 9.01±0.15 km2. The analysis of the climate variables (Tmax, Tmin, and average precipitation) using Mann–Kendall and regression tests revealed increasing temperatures [Tmax (1.12°C) and Tmin (0.81°C)] and decreasing precipitation (198 mm) trends in the region. Furthermore, correlation analysis revealed a significant positive correlation between glacier area and precipitation (0.897), but a negative correlation with the glacial lake area (−0.994), Tmax (−0.743), and Tmin (−0.789). This signifies that expansion of PDGLs and melting of feeding glaciers are the result of the changing climatic regime in the region, which is in line with the findings of other studies carried out in different parts of the Himalayan region.