Links between tropical rainfall and North Atlantic climate during the last glacial period

International audienceDuring the last glacial period, the North Atlantic regionexperienced pronounced, millennial-scale alternations between cold, stadial conditions and milder interstadialconditions—commonly referred to as Dansgaard–Oeschgeroscillations—as well as periods of massive iceberg dischargeknown as Heinrich events1. Changes in Northern Hemispheretemperature, as recorded in Greenland2–4, are thought to haveaffected the location of the Atlantic intertropical convergencezone5,6 and the strength of the Indian summer monsoon7,8.Here we use high-resolution records of sediment colour—ameasure of terrigenous versus biogenic content—from theCariaco Basin off the coast of Venezuela and the ArabianSea to assess teleconnections with the North Atlantic climatesystem during the last glacial period. The Cariaco recordindicates that the intertropical convergence zone migratedseasonally over the site during mild stadial conditions, but waspermanently displaced south of the basin during peak stadialsand Heinrich events. In the Arabian Sea, we find evidence ofa weak Indian summer monsoon during the stadial events.The tropical records show a more variable response to NorthAtlantic cooling than the Greenland temperature records. Wetherefore suggest that Greenland climate is especially sensitiveto variations in the North Atlantic system—in particular sea-iceextent—whereas the intertropical convergence zone and Indianmonsoon system respond primarily to variations in meanNorthern Hemisphere temperature