Large and abrupt increases in Antarctic snowfall during Heinrich Stadials

During the last glacial period, the North Atlantic region experienced cold intervals characterized by significant iceberg discharge events. These intervals, known as Heinrich Stadials, coincided with abrupt climate shifts observed globally. In Antarctica, the accelerated warming was identified from ice-core isotopic records, but changes in precipitation has remained unknown. Here, we present accumulation-rate reconstructions for the last glacial period at centennial resolutions for four ice core sites in East Antarctica. Surprisingly, large and rapid accumulation increases on a millennial timescale occurred during the Heinrich stadials beyond what is expected from the site warming amplitudes. The sensitivity of accumulation rate to surface temperature for these events could be up to 27% K-1, which is more than double the Antarctic modern sensitivity. The increased snowfall may be attributed to enhanced atmospheric moisture content or meridional transport, which in turn may be driven by a cascade of southward shift of the Intertropical Convergence Zone (ITCZ), southward shift and strengthening of Southern Hemisphere westerly winds, and enhanced wind-driven upwelling of Southern Ocean deep water. Increased frequency or intensity of direct moisture transport may also play a crucial role. Our results provide a consistent picture of southern high-latitude hydrological changes linked to global climate perturbation , with potential implications for current anthropogenic warming.