Abstract
Abstract The year 2025, designated by the United Nations as the ‘International Year of Glaciers’ Preservation’, ironically became the most negative glacier mass-balance year on record in Central Asia. In situ observations reveal exceptionally strong and spatially coherent ice losses across the region, although not all individual glaciers experienced record losses. Regional simulations with the Global Glacier Evolution Model support these findings, indicating that 64% of glaciers larger than 1 km 2 (∼4000 glaciers) reached their most negative annual mass balance within the study period. Within a single year, glaciers in Central Asia lost an estimated 30 ± 6 km 3 of ice (26 ± 9 Gt), corresponding to ∼2% of their present-day total mass. Mass loss was strongest in the western Tien Shan and western Pamir (−2% to −4%) and more moderate in the eastern Tien Shan and eastern Pamir (−1% to −1.5%). Climate reanalysis attributes the extreme 2025 losses to persistently above-average spring and summer temperatures, an unusually early onset of the melt season, and reduced snowfall frequency during late spring and summer. Together, these conditions enhanced melt-amplifying feedbacks by accelerating snow loss, leading to earlier exposure of low-albedo ice surfaces. The 2025 losses mark an alarming milestone for Central Asian glaciers and may become the new normal in the future.