Rapid Indian Monsoon response to the Younger Dryas event in the Southeastern Tibetan Plateau

Abstract

The Younger Dryas (YD) was a large-scale abrupt climate event during the last deglaciation with wide-ranging effects on the global environment. Here, we present an absolute dated speleothem oxygen isotope record (δ¹⁸O) of Indian Summer Monsoon (ISM) variability from Shenqi Cave in the southeastern Tibetan Plateau (TP) across the YD event. The δ¹⁸O of SQ8 increased markedly by ∼4 ‰ during the YD, which is substantially larger than other coeval stalagmite δ¹⁸O records from the East Asian and Indian monsoon regions. This distinct increase may be ascribed to the combined influences of the altitude effect and the diminished transpiration from vegetation. Our data indicate an abrupt increase in ISM strength occurred in tandem with the termination of the Younger Dryas (∼76 years). The ISM's rapid response to the YD event may be due to the TP's location upstream of Rossby waves, as well as the enhanced feedback caused by the surface ice and snow cover. Our data further indicate that multidecadal variations in ISM intensity are positively correlated with the Atlantic Multidecadal Oscillation (AMO) amplitude, modulated by long-term solar radiation and sea ice changes.