The evolution of ENSO in postglacial period

Matthew Makou, Timothy Eglinton, Delia Oppo, and Konrad Hughen, Postglacial changes in El Niño and La Niña behavior, Geology 38, 43–46

Surface ocean productivity off the coast of Peru is strongly associated with the El Niño–Southern Oscillation (ENSO). Using two compounds produced by marine life and preserved in sediment—dinosterol as a proxy for El Niño and cholesterol for La Niña—the authors produce the first parallel reconstructions of warm- and cold-phase variability over the past 16,000 years. The data indicate persistent La Niña–like conditions, driven by the influence of retreating glaciers on trade winds, until about 11,500 years ago. After glaciers stabilized and the influence of low-latitude insolation became dominant, both El Niño and La Niña appear to have intensified starting about 2,000 years ago.