Sudden weakening of the Indian Summer Monsoon during the Younger Dryas

Understanding Indian Summer Monsoon (ISM) variability in the context of global climate is critical for predicting and forecasting its impacts in an evolving future climate change scenario, thereby achieving sustainable economic growth. This study presents speleothem oxygen isotope-based inferences regarding changes in ISM conditions during the marine isotope stage 2 (MIS-2). The study suggests a strong summer monsoon during global warm phases and a weak monsoon in cold intervals. The ISM was weak during 26–19 kyr BP, while strengthened between 19 and 12.8 kyr BP. The western Himalaya suffered a rapid reduction in ISM precipitation at around 12.8 kyr BP linked to the global cooling and weakened oceanic circulation at the onset of the Younger Dryas (YD) interval. Sea-ice expansion in the North Atlantic led to cooling in the western Himalaya through westerlies and caused a reduction in ISM precipitation in the Indian subcontinent. After the YD, the climate became warm with the onset of the Holocene, and ISM conditions significantly improved.