Cryosphere-hydrosphere interactions under intensifying dryland climate stress: Evidence from glacier-fed lakes in the Munkh-Khairkhan Mountains, Western Mongolia

Cryosphere–hydrosphere interactions are rapidly intensifying in mid-latitude mountain regions, yet their combined impacts on lake water availability remain insufficiently understood. We quantified glacier area change, lake dynamics, hydrochemical characteristics, and isotopic tracers of six glacier-fed lakes connected to the upper Munkhkhairkhan Glacier in western Mongolia over the period 1990–2024. Results show substantial glacier loss (−38.1%) and persistent lake shrinkage (−2.54%), driven primarily by rising atmospheric dryness. Vapor pressure deficit (VPD) is identified as the dominant predictor of lake contraction, while hydrological moisture indicators (precipitation minus evapotranspiration, P–PET, and Palmer Drought Severity Index, PDSI) exert rapid but weaker positive influence. Principal Component Analysis (PCA) reveals two distinct climate modes: an atmospheric-drying mode explaining 79% of variability and a hydrological-moisture mode explaining 13%. Projections indicate continued lake losses by 2030–2040, with stronger declines in downstream basins. Hydrochemical enrichment and isotopically heavier signatures in lower-elevation lakes indicate enhanced evaporation and increasing dependence on seasonal rainfall. These findings highlight growing vulnerability of glacier-fed water systems and underscore the urgent need for adaptive water management in cold–arid mountain environments.