Evolution of a debris-covered glacier in the western Himalaya during the last four decades (1971–2016): A multiparametric assessment using remote sensing and field observations

Abstract This study assesses the response of the Panchi Nala glacier, Bhaga Basin, western Himalaya to climate change by monitoring multiple glacier parameters namely, length, area, debris cover, snowline altitude ( SLA ), surface ice velocity ( SIV ), and surface elevation change (Δ h ). These parameters were analysed using high-resolution satellite images (Corona KH-4B and Sentinel-2 MSI) and medium-resolution ones (Landsat TM/ETM+/OLI and Terra ASTER) acquired between 1971 and 2016, along with extensive field observations. Considering only dimensional changes, the glacier appears to have low rates of recession (4.54 ± 2.56 m y −1 ) and deglaciation (0.11 ± 0.04% y −1 ) over the study period (1971–2016). However, SIV and Δ h values reveal a significant slowdown (33.87%; 1992/93–2015/16), and an extensive lowering (−1.62 ± 0.06 m y −1 ; 2000–2013) on the glacier. The debris cover area and SLA also increased by 23.50 ± 1.74% and 287.63 m, respectively, during 1971–2016. Increase in the mean winter minimum temperature, and decrease in the winter snowfall are probably the main drivers of glacier depletion. We conclude that the significant slowdown, extensive surface lowering, development of a proglacial lake and appearance of the supraglacial lakes collectively indicate a severe glacier degeneration. This forewarns that the glacier may experience an accelerated pace of wastage in the future.