Ocean circulation, ice shelf, and sea ice interactions explain Dansgaard–Oeschger cycles

• Published in: Proceedings of the National Academy of Sciences
• Main Authors: Boers, Niklas, Ghil, Michael, Rousseau, Denis-Didier
• Other Authors: Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL), Potsdam-Institut für Klimafolgenforschung (PIK), Grantham Institute for Climate Change and the Environment, Imperial College London, Department of Atmospheric and Oceanic Sciences Los Angeles (AOS), University of California Los Angeles (UCLA), University of California (UC)-University of California (UC), Lamont-Doherty Earth Observatory (LDEO), Columbia University New York
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: millennial climate variability; nonlinear climate modeling; north–south seesaw; Bayesian parameter estimation; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; Antarctic; Greenland; Antarc*; Antarctica; Greenland ice cores; Ice Shelf; Ice Shelves; Sea ice
• Online Access: https://hal.science/hal-02352633; https://hal.science/hal-02352633/document; https://hal.science/hal-02352633/file/DDR_PNAS2018Boers.pdf; https://doi.org/10.1073/pnas.1802573115

International audience Paleoclimatic proxy records from Greenland ice cores show that the last glacial interval was punctuated by abrupt climatic transitions called Dansgaard–Oeschger (DO) events. These events are characterized by temperature increases over Greenland of up to 15°C within a few decades. The cause of these transitions and their out-of-phase relationship with corresponding records from Antarctica remains unclear. Based on earlier hypotheses, we propose a model focusing on interactions between ice shelves, sea ice, and ocean currents to explain DO events in Greenland and their Antarctic counterparts. Our model reproduces the main features of the observations. Our study provides a potential explanation of DO events and could help assess more accurately the risk of abrupt climatic transitions in the future.