Super ENSO and Global Climate Oscillations at Millennial Time Scales

• Published in: Science
• Main Authors: Stott, Lowell, Poulsen, Christopher, Lund, Steve, Thunell, Robert
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Association for the Advancement of Science (AAAS) 2002
• Subjects: Greenland; Pacific; Planktonic foraminifera
• Online Access: http://dx.doi.org/10.1126/science.1071627; https://www.science.org/doi/pdf/10.1126/science.1071627

The late Pleistocene history of seawater temperature and salinity variability in the western tropical Pacific warm pool is reconstructed from oxygen isotope (δ 18 O) and magnesium/calcium composition of planktonic foraminifera. Differentiating the calcite δ 18 O record into components of temperature and local water δ 18 O reveals a dominant salinity signal that varied in accord with Dansgaard/Oeschger cycles over Greenland. Salinities were higher at times of high-latitude cooling and were lower during interstadials. The pattern and magnitude of the salinity variations imply shifts in the tropical Pacific ocean/atmosphere system analogous to modern El Niño–Southern Oscillation (ENSO). El Niño conditions correlate with stadials at high latitudes, whereas La Niña conditions correlate with interstadials. Millennial-scale shifts in atmospheric convection away from the western tropical Pacific may explain many paleo-observations, including lower atmospheric CO 2 , N 2 O, and CH 4 during stadials and patterns of extratropical ocean variability that have tropical source functions that are negatively correlated with El Niño.