Investigation of glacier mass balance based on multi-source observation in the Karakoram over the past 25 years

The "Karakoram Anomaly" - the atypical stability of glaciers in a warming climate-has introduced considerable uncertainty into projections of regional water resources. However, the resilience of this anomaly under sustained climate forcing remains poorly quantified. In this study, multi-source geodetic data (ASTER, NASA DEM, ICESat‑2) were integrated to reassess glacier mass balance across the Karakoram and its sub‑regions between 2000 and 2024. Our results indicate a region‑wide specific mass balance of -0.0386 ± 0.0032 m w.e. a - ¹, with strong spatio-temporal heterogeneity. We document a progressive decay of the Karakoram Anomaly: it was region‑wide before 2010, contracted to the northern and central Karakoram during 2010-2020, and has largely weakened since 2020, persisting only in isolated basins. This evolution is closely associated with summer warming and changes in precipitation. Topography exerts a key control on spatial variability. These findings improve our understanding of the Karakoram anomaly and are of great significance for regional water resources management and disaster prevention under climate change.