Persistent influence of ice sheet melting on high northern latitude climate during the early Last Interglacial

• Published in: Climate of the Past
• Main Authors: Govin, Aline, Braconnot, Pascale, Capron, Émilie, Cortijo, Elsa, Duplessy, Jean-Claude, Jansen, Eystein, Labeyrie, Laurent, Landais, Amaëlle, Marti, Olivier, Michel, Elisabeth, Mosquet, Eloi, Risebrobakken, B., Swingedouw, Didier, Waelbroeck, C.
• Other Authors: Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), 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)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Climat et Magnétisme (CLIMAG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID), Paléocéanographie (PALEOCEAN), Bjerknes Centre for Climate Research (BCCR), Department of Biological Sciences Bergen (BIO / UiB), University of Bergen (UiB)-University of Bergen (UiB), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2012
• Subjects: [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; Ice Sheet; Labrador Sea; North Atlantic; Norwegian Sea; Southern Ocean
• Online Access: https://hal.science/hal-02180961; https://hal.science/hal-02180961/document; https://hal.science/hal-02180961/file/Govin-CP2012.pdf; https://doi.org/10.5194/cp-8-483-2012

International audience Although the Last Interglacial (LIG) is often considered as a possible analogue for future climate in high latitudes , its precise climate evolution and associated causes remain uncertain. Here we compile high-resolution marine sediment records from the North Atlantic, Labrador Sea, Norwegian Sea and the Southern Ocean. We document a delay in the establishment of peak interglacial conditions in the North Atlantic, Labrador and Norwegian Seas as compared to the Southern Ocean. In particular, we observe a persistent iceberg melting at high northern latitudes at the beginning of the LIG. It is associated with (1) colder and fresher surface-water conditions in the North Atlantic, Labrador and Nor-wegian Seas, and (2) a weaker ventilation of North Atlantic deep waters during the early LIG (129-125 ka) compared to the late LIG. Results from an ocean-atmosphere coupled model with insolation as a sole forcing for three key periods of the LIG show warmer North Atlantic surface waters and stronger Atlantic overturning during the early LIG (126 ka) than the late LIG (122 ka). Hence, insolation variations alone do not explain the delay in peak interglacial conditions observed at high northern latitudes. Additionally, we consider an idealized meltwater scenario at 126 ka where the freshwater input is interactively computed in response to the high bo-real summer insolation. The model simulates colder, fresher North Atlantic surface waters and weaker Atlantic overturning during the early LIG (126 ka) compared to the late LIG (122 ka). This result suggests that both insolation and ice sheet melting have to be considered to reproduce the climatic pattern that we identify during the early LIG. Our model-data comparison also reveals a number of limitations and reinforces the need for further detailed investigations using coupled climate-ice sheet models and transient simulations.