Climate Constraints on Glaciation Over High-Mountain Asia During the Last Glacial Maximum

Abstract

Reasons for restricted and nonuniform glaciation over High-Mountain Asia (HMA) during the global last glacial maximum (LGM; ~28-23 ka) have been intensively studied but remain elusive. Using a 1-km-resolution ice sheet model, we show that glaciers across HMA exhibit high region variability in glaciation. Glaciers in western and southern HMA are the most sensitive to climate change and those in the interior are the least sensitive. Our model broadly reproduces the restricted glaciation across HMA during the LGM, although it overestimates the extent of glaciation over western and southern HMA as compared with reconstructions. Modeled decreases in precipitation hampers glacier growth over northern HMA, while insufficient cooling hampers glacier advance over eastern HMA for the LGM. Both reduced precipitation and insufficient cooling inhibit large-scale glaciation over inner HMA. Moreover, climatic conditions conducive to glaciation across the entire HMA include a reduction in temperature of ~10 °C and an increase in precipitation, unlikely to have occurred during any Quaternary glacial maximum.