Rates of High Mountain Asian Glacier Ice Loss from ICESat-2 Observations

The importance of glaciers in High Mountain Asia (HMA) is significant in sustaining mountain hydrology and the runoff of several river systems that originate from these glaciers. The availability of numerous remote sensing products provides an opportunity to assess the current regional glacier mass balance comprehensively. We updated and presented recent glacier mass loss from the HMA and regional variability using Ice, Cloud, and Land Elevation Satellite (ICESat-2) data from October 2018 to December 2021. The HMA experienced accelerated mass loss in recent years of -62.62 ± 11.81 Gt a^-1, (-17.11 ± 2.89 m w.e a^-1). All 22 regions of HMA lost mass during the study period, regional mass loss range between -0.28 ± 0.47 m w.e. a^-1 in the Western Kunlun Shan and -1.71 ± 0.22 m w.e. a^-1 in the Hengduan Shan. The highest mass loss occurred at Hengduan Shan, East Tibetan Mountains, and Nyainqentanglha. Glaciers within the altitude range up to 4000 m a.s.l experienced the most negative mass balance. In recent years glacier mass loss increased by more than two-fold compared to previous studies even in the regions where glaciers were previously in balance or less negative mass balance such as Western Kunlun Shan (-0.28 ± 0.47 m w.e. a^-1), Eastern Pamir (-0.47 ± 0.374 m w.e. a^-1), and Karakoram (-0.61 ± 0.40 m w.e. a^-1). The complex regional pattern of variable glacial mass balance and recent mass loss can be attributed to heterogeneous climate change signals and changes in meteorological conditions over the regions.