Glacier changes and associated climate drivers for the last three decades, Nanda Devi region, Central Himalaya, India

The glaciers are considered as iconic indicators of climate change, and receding at differential rates worldwide. Variable retreat rates of glacier termini and inadequate supporting field data (e.g. mass balance, ice thickness, velocity, etc.) of the glaciers makes it difficult to access the impact of climate change. Here, we examined eight glaciers in the upper Rishi Ganga catchment, Nanda Devi region, Central Himalaya, India, to assess their spatial and temporal variability towards the climate change. The temporal coverage of analysis spans from twentieth to early twenty-first centuries (ranges 1980 to 2017). The study was designed by comparing the estimates of different temporal satellite images of the Hexagon KH-9 (1980) with Landsat 5 TM (1989), Landsat 7 ETM+ (1999), Landsat 8 OLI/TRIS (2017) and ASTER DEM (2011) with local and regional meteorological conditions of the study area. The upper Rishi Ganga catchment covers an area of similar to 690 km(2), having a glaciated area of similar to 243 km(2) (similar to 35% of the total area) during 1980. Our study reveals that the glaciers of the valley lost similar to 26 km(2) (10%) of the glaciated area between 1980 and 2017. The total glacierized area in 2017 is similar to 217 km(2), which is similar to 26% of the total area. However, during the same periods (1980-2017) the Equilibrium Line Altitude (ELA) of the glaciers fluctuated between 5200 and 5700 m asl. The present study suggests that the glaciers in the region have responded to deprived precipitation conditions since 1980, overlapping our understanding of glacier retreat due to temperature increase, in the context of the global warming scenario.

Automated summary

Glaciers in the upper Rishi Ganga catchment in the Central Himalayas of India have decreased in area by 10% since 1980, with a total glacierized area of 217 square kilometers in 2017, representing 26% of the total area. However, during the same period, the Equilibrium Line Altitude (ELA) of the glaciers fluctuated between 5200 and 5700 meters above sea level. This suggests that the glaciers in the region have responded to decreased precipitation conditions since 1980, in line with the global warming scenario.