The differential impact of global temperature trends on prolonged droughts in the Indian Monsoon realm during the past five millennia

Given the uncertainties in projecting future precipitation seasonality and droughts in the Indian Summer Monsoon realm (ISMr) in a heterogeneous global warming scenario, understanding past hydroclimate responses to regional/hemispheric co( di )vergent temperature trends and shifting teleconnections is crucial. This study presents a comprehensive hydroclimate overview of the past 5 cal ka in the ISMr by integrating existing records with new data from the amplifier Manasbal Lake (NW Himalaya). Our findings identify two major reorganizations of seasonal precipitation pathways linked to temperature trends in high-latitude and tropical regions, which triggered asynchronous prolonged droughts (PDs) in the NW Himalaya (3.9–2.9 cal ka) and the core monsoon zone (CMZ) (4.6–3.9 and 1.2–0.6 cal ka). The first reorganisation, around ~5 cal ka, coincided with simultaneous cooling in both high-latitude and tropical regions, driving a southward shift of the winter westerlies and resulting in winter droughts in the NW Himalaya (5–2.9 cal ka). Concurrently, a northward-shifted ISM caused a PD in the CMZ (4.6–3.9 cal ka). Within this interval, diminishing east–west ISM rainfall (3.9–2.9 cal ka) and reduced winter precipitation culminated in a severe PD in Manasbal Lake. The second reorganisation (~1.2 cal ka), coincided with divergent temperature trends—cooling in the high-latitude Northern Hemisphere and warming in the tropics, and increased ENSO activity causing a second PD in the CMZ (1.2–0.6 cal ka). Our results highlight the importance of considering the complexities in regional temperature trends in refining predictive climate models. • First high resolution, continuous, well dated multiproxy reconstruction from westerlies-Indian monsoon region for past 5 cal ka. • Reconstructs asynchronous multicentennial seasonal droughts in Indian Summer Monsoon realm. • Identifies the mechanisms by which global temperature trends modify teleconnections, altering seasonal precipitation pathways and triggering droughts in the ISMr.