Hydrogen Isotopic Records Reveal Drying in Equatorial Africa during the 8.5 ka Drainage of Glacial Lake Agassiz

North Atlantic freshening events are known to have perturbed ocean circulation and tropical hydrology during the last ice age but impacts of these events on tropical climate during globally warm time periods such as the Holocene are more poorly known. A massive North Atlantic freshwater flood event about 8.5 thousand year ago (ka), which triggered the so-called 8.2 ka event, should provide insights into how ice sheet disintegration and freshwater release may produce abrupt hydrological changes in the tropics. Here, a mixture of paleohydrological proxies--primarily the hydrogen-isotopic composition of leaf-wax lipid biomarkers--analyzed within a sediment core from Lake Edward, located in equatorial Africa, provide evidence of rapid drying at about the time of the 8.5 ka flood event. We observe a +20‰ deuterium-enrichment event from 8.6-8.4 ka, followed by a return to mid-Holocene levels by 8 ka. We observe a similar response in lake salinity indicators, which also rise from 8.6-8.4 ka and fall to stable mid-Holocene levels by 8 ka. The timing and structure of the drying suggest equatorial African drought was triggered by a reduction in the Atlantic Meridional Overturning Circulation (AMOC), which we attribute to the North Atlantic outburst event. Interestingly, drying in equatorial Africa appears in phase with the glacial meltwater outburst but leads northern high-latitude climatic response as recorded in Greenland ice cores (~8.2 ka), potentially constraining the mechanisms transmitting signals from the high to low latitudes.