Causes of ice age intensification across the Mid-Pleistocene Transition

• Published in: Proceedings of the National Academy of Sciences
• Main Authors: Chalk, Thomas, B, Hain, Mathis, Foster, Gavin, Rohling, Eelco, Sexton, Philip, Badger, Marcus, Cherry, Soraya, Hasenfratz, Adam, Haug, Gerald, Jaccard, Samuel, Martínez-García, Alfredo, Pälike, Heiko, Pancost, Richard, Wilson, Paul
• Other Authors: Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), National Oceanography Centre Southampton (NOC), University of Southampton, Australian National University (ANU), The Open University Milton Keynes (OU), Max Planck Institute for Chemistry (MPIC), Max-Planck-Gesellschaft, Université de Lausanne = University of Lausanne (UNIL), Center for Marine Environmental Sciences Bremen (MARUM), Universität Bremen, Organic Geochemistry Unit - OGU (Bristol, United Kingdom), University of Bristol Bristol, University of Wolverhampton
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: [SDE]Environmental Sciences; Southern Ocean; Ice Sheet
• Online Access: https://hal.science/hal-04698938; https://doi.org/10.1073/pnas.1702143114

International audience Significance Conflicting sets of hypotheses highlight either the role of ice sheets or atmospheric carbon dioxide (CO 2 ) in causing the increase in duration and severity of ice age cycles ∼1 Mya during the Mid-Pleistocene Transition (MPT). We document early MPT CO 2 cycles that were smaller than during recent ice age cycles. Using model simulations, we attribute this to post-MPT increase in glacial-stage dustiness and its effect on Southern Ocean productivity. Detailed analysis reveals the importance of CO 2 climate forcing as a powerful positive feedback that magnified MPT climate change originally triggered by a change in ice sheet dynamics. These findings offer insights into the close coupling of climate, oceans, and ice sheets within the Earth System.