Ventilation of the deep Southern Ocean and deglacial CO2 rise

• Published in: Science
• Main Authors: Skinner, Luke C., Fallon, Stewart J., Waelbroeck, C., Michel, Elisabeth, Barker, Stephen
• Other Authors: Department of Earth Sciences Cambridge, UK, University of Cambridge UK (CAM), Research School of Earth Sciences Canberra (RSES), Australian National University (ANU), Paléocéanographie (PALEOCEAN), Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), School of Earth and Ocean Sciences Cardiff, Cardiff University
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2010
• Subjects: geo; envir; Antarctic; Southern Ocean; The Antarctic; Antarc*; Antarctica
• Online Access: https://doi.org/10.1126/science.1183627; https://hal-cea.archives-ouvertes.fr/cea-00818324

International audience Past glacial-interglacial increases in the concentration of atmospheric carbon dioxide (CO$_2$ ) are thought to arise from the rapid release of CO$_2$ sequestered in the deep sea, primarily via the Southern Ocean. Here, we present radiocarbon evidence from the Atlantic sector of the Southern Ocean that strongly supports this hypothesis. We show that during the last glacial period, deep water circulating around Antarctica was more than two timesolder than today relative to the atmosphere.During deglaciation, the dissipation of this old and presumably CO$_2$ -enriched deep water played an important role in the pulsed rise of atmospheric CO$_2$ through its variable influence on the upwelling branch of the Antarctic overturning circulation.