What Ends an Interglacial? Feedbacks Between Tropical Rainfall, Atlantic Climate and Ice Sheets During the Last Interglacial

Abstract

How long the present interglacial will last remains under debate. This project aims to determine the climatic mechanisms and sequence of events termi-nating an interglacial period. By comparing new paleoclimate reconstructions and climate model experiments, we investigate the impact of South American rainfall changes on tropical Atlantic sea-surface salinity and Atlantic thermohaline circu-lation at the end of the Last Interglacial (LIG). Model and proxy data show grad-ually intensifying South American monsoonal precipitation and enhanced Amazon discharge through the LIG, in response to increasing austral summer insolation. However, an increased meridional temperature gradient at the end of the LIG caused a strengthening of the North Brazil Current retroflection which deflected eastward the Amazon freshwater plume. Such changes in South American river discharge contributed to decrease tropical and North Atlantic surface salinities, resulting in a shift in regions of North Atlantic deep water convection and small reduction in deep water formation.