El Niño–Southern Oscillation strengthened by North Atlantic Iceberg discharge during Heinrich stadial 1

The last deglaciation provides an opportunity to assess the response of El Niño–Southern Oscillation to rapid warming and disruptions of the Atlantic Meridional Overturning Circulation, both projected in the near future. We present a reconstruction of deglacial El Niño–Southern Oscillation activity using finely laminated sediments from the El Niño–Southern Oscillation-sensitive Peruvian margin. An interannual record of titanium fluxes, a proxy for riverine discharge, shows that the frequency of extreme Eastern Pacific El Niño events and the amplitude of El Niño–Southern Oscillation variability were higher during the deglaciation and peaked during episodes of massive iceberg discharge into the North Atlantic. Maximum El Niño–Southern Oscillation variability occurred in the early phase of Heinrich event 1, at ~17.3–16.7 kyr BP, associated with at least five extreme floods per century in southern Peru. This proxy evidence linking El Niño–Southern Oscillation and the North Atlantic suggests a possible increase in El Niño-related extreme climatic events under future Atlantic Meridional Overturning Circulation weakening.