Monsoon forcings and feedbacks in a warm climate state

The Indian summer monsoon (ISM) occurs within the word’s strongest hydrological regime and its rainfall and wind patterns affect the livelihoods of billions of people. Globally, the area influenced by monsoon systems is predicted to increase over the 21st century as a result of anthropogenic temperature and greenhouse gas forcing. However, model uncertainty for projections of monsoon rainfall is high, and the instrumental record is too short to resolve natural monsoon variability and forcings. Many fundamental questions on the functioning and feedbacks of the ISM, which varies on seasonal to tectonic timescales, remain unanswered.

The iMonsoon project aims to reconstruct past climate and ISM variability during the warm late Miocene (9-5 Ma) via the application of multiple geochemical and micropaleontological proxies to a new unique sediment core from the Bay of Bengal (IODP Site U1443), located in the core convective region of the ISM.

Results from this project will contribute to answering important questions, namely (1) the sensitivity and timing of changes in monsoon circulation relative to external insolation forcing and internal boundary conditions including the export of latent heat from the southern hemisphere, the extent of global ice volume, and greenhouse gas concentrations, and (2) the timing and conditions under which monsoonal circulation initiated and evolved, and (3) the degree of coupling between the various subsystems of the Asian monsoon.