Future projections of glacier mass change in High Mountain Asia using GRACE and climatemodel data

High Mountain Asia (HMA) is a critical region for global water resources, where glacier monitoring, modeling, and prediction are essential to understanding the impacts of climate change on water availability and related hazards. This study examined glacier mass change in HMA using terrestrial water storage anomaly data from gravity recovery and climate experiment (GRACE) and GRACE Follow-On. Our results reveal significant glacier mass loss of - 13.9 ± 3.6 Gt/yr between 2002/03 and 2022/23, with pronounced spatial variability across subregions. Eastern Kunlun shows the highest mass gain (1.1 ± 0.2 Gt/yr), while the West Tien Shan experiences the most rapid mass loss (-1.9 ± 0.4 Gt/yr). For future projections, we employed a generalized additive model driven by climate and radiative flux variables from the Inter-Sectoral Impact Model Intercomparison Project under low- (SSP126) and high-emission (SSP585) scenarios. The results indicate continued glacier mass decline, with the steepest reductions under SSP585 (- 19.5 ± 11.3 Gt/yr) compared to SSP126 (- 2.3 ± 0.3 Gt/yr). These changes occurred due to variation in climatic and radiative fluxes in both past and future projections. Overall, our study enhances understanding of cryospheric change in HMA, providing critical insights for future research, climate adaptation, and water resource management.