Climate proxy data and numerical models suggest that latitudinal displacements of the Intertropical Convergence Zone (ITCZ) occur during millennial-scale cold events in the North Atlantic region, but the potential effects of these ITCZ movements on the climate of equatorial regions are unclear. Here we present a 5400-year geochemical record of rainfall and drought from Lake Edward in equatorial Africa. We observe a non-linear correlation in which drought in equatorial Africa occurs during both cold and warm extremes in the North Atlantic's 1500-year quasi-cycle. We propose that this relationship occurs due to northward/ southward displacement of the ITCZ from its equatorial mean position during warm/cold events. Our results show that millennial-scale high-latitude climate events are linked to changes in equatorial terrestrial climate even during the late Holocene and suggest important constraints on the mechanisms linking tropical and extratropical climate variability.
Copyright 2008 Elsevier B.V., All rights reserved.