Collaborative Research: P2C2--Evaluating the Origins of Multidecadal Variability in Late Holocene Indian Summer Monsoon Rainfall in Nepal

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The research team aims to develop a replicated, 4000-year-long, precisely dated, sub-decadally resolved, multi-proxy stalagmite reconstruction of Indian Summer Monsoon (ISM) rainfall in Nepal and to couple this record with climate model simulations to examine the nature and origins of multidecadal monsoon variability during different climate states of the late Holocene. The ISM supplies nearly seventy percent of South Asia’s annual precipitation, serving as the primary water resource for agriculture and the myriad of natural environments, including glaciers, across the region. Over the last century and a half, ISM rainfall has been positively correlated at multidecadal time scales with sea surface temperatures in the North Atlantic Ocean. However, in the last twenty years, this link appears to have been broken, with monsoon rainfall over India failing to increase despite a much warmer North Atlantic. This shift has profound consequences for regional ecosystems and the approximately two billion people living in South Asia. The potential Broader Impacts include a deeper understanding of a climatological system which impacts large human population centers, capacity building and expertise exchange with international colleagues, support of students involved with the research, and public outreach.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.