Ocean as the main driver of Antarctic ice sheet retreat during the Holocene

• Published in: Global and Planetary Change
• Main Authors: Crosta, Xavier, Crespin, Julien, Swingedouw, Didier, Marti, Olivier, Masson-Delmotte, Valérie, Etourneau, Johan, Goosse, Hugues, Braconnot, Pascale, Yam, Ruth, Brailovski, Irena, Shemesh, Aldo
• Other Authors: Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Department of Earth and Planetary Science Rehovot, Weizmann Institute of Science Rehovot, Israël, Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS), CERFACS, 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), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), 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), Instituto Andaluz de Ciencias de la Tierra (IACT), Universidad de Granada (UGR)-Consejo Superior de Investigaciones Científicas Madrid (CSIC), Institut d'Astronomie et de Géophysique Georges Lemaître (UCL-ASTR), Université Catholique de Louvain = Catholic University of Louvain (UCL), Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID), Department of Environmental Sciences and Energy Research Rehovot
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; Antarctic; Antarctic Peninsula; East Antarctica; Prydz Bay; Southern Ocean; The Antarctic; West Antarctica; Antarc*; Antarctica; ice core; Ice Sheet; Ice Shelf; Ice Shelves
• Online Access: https://hal.archives-ouvertes.fr/hal-02105534; https://doi.org/10.1016/j.gloplacha.2018.04.007

International audience Ocean-driven basal melting has been shown to be the main ablation process responsible for the recession of many Antarctic ice shelves and marine-terminating glaciers over the last decades. However, much less is known about the drivers of ice shelf melt prior to the short instrumental era. Based on diatom oxygen isotope (δ18Odiatom; a proxy for glacial ice discharge in solid or liquid form) records from western Antarctic Peninsula (West Antarctica) and Adélie Land (East Antarctica), higher ocean temperatures were suggested to have been the main driver of enhanced ice melt during the Early-to-Mid Holocene while atmosphere temperatures were proposed to have been the main driver during the Late Holocene. Here, we present a new Holocene δ18Odiatom record from Prydz Bay, East Antarctica, also suggesting an increase in glacial ice discharge since ~4500 years before present (~4.5 kyr BP) as previously observed in Antarctic Peninsula and Adélie Land. Similar results from three different regions around Antarctica thus suggest common driving mechanisms. Combining marine and ice core records along with new transient accelerated simulations from the IPSL-CM5A-LR climate model, we rule out changes in air temperatures during the last ~4.5 kyr as the main driver of enhanced glacial ice discharge. Conversely, our simulations evidence the potential for significant warmer subsurface waters in the Southern Ocean during the last 6 kyr in response to enhanced summer insolation south of 60°S and enhanced upwelling of Circumpolar Deep Water towards the Antarctic shelf. We conclude that ice front and basal melting may have played a dominant role in glacial discharge during the Late Holocene.