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.