Persistent influence of ice sheet melting on high northern latitude climate during the early last interglacial

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doi: 10.5194/cp-8-483-2012
Author(s): Govin, Aline; Braconnot, Pascale; Capron, Emilie; Cortijo, Elsa; Duplessy, Jean-Claude; Jansen, Eystein; Labeyrie, Laurent; Landais, Amaelle; Marti, Olivier; Michel, Elisabeth; Mosquet, Eloi; Risebrobakken, Bjorg; Swingedouw, Didier; Waelbroeck, Claire
Author Affiliation(s): Primary:
Institute Pierre Simon Laplace, Laboratoire des Sciences du Climat et de l'Environnement, Gif-sur-Yvette, France
Other:
University of Bergen, Norway
Volume Title: Climate of the Past
Source: Climate of the Past, 8(2), p.483-507. Publisher: Copernicus, Katlenburg-Lindau, International. ISSN: 1814-9324
Note: In English. Published in Climate of the Past Discussion: 11 October 2011, http://www.clim-past-discuss.net/7/3239/2011/cpd-7-3239-2011.html; accessed in June, 2012. 137 refs.; illus., incl. 4 tables, sketch maps
Summary: 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 Norwegian 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 boreal 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.
Year of Publication: 2012
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Aliphatic hydrocarbons; Alkanes; Arctic Ocean; Arctic region; Atlantic Ocean; Boreal environment; C-13; C-13/C-12; Carbon; Carbon dioxide; Cenozoic; Climate forcing; Detritus; Foraminifera; Glacial geology; Greenland; Greenland ice sheet; Hydrocarbons; IPSL-CM4; Ice rafting; Ice sheets; Icebergs; Insolation; Interglacial environment; Invertebrata; Isotope ratios; Isotopes; Labrador Sea; Leg 162; MIS 5; Melting; Meltwater; Methane; Microfossils; Nitrous oxide; North Atlantic; Norwegian Sea; O-18/O-16; ODP Site 980; Ocean Drilling Program; Organic compounds; Oxygen; Paleoclimatology; Pleistocene; Protista; Quaternary; Rockall Bank; Stable isotopes; Terrestrial environment
Coordinates: N552906 N552906 W0144208 W0144208
Record ID: 2012069080
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Copernicus Gesellschaft, Katlenburg-Lindau, Germany