Global budget of water isotopes inferred from polar ice sheets

• Published in: Geophysical Research Letters
• Main Authors: Lhomme, N., Clarke, Garry K. C., Ritz, Catherine
• Other Authors: Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Earth and Ocean Sciences (EOS), University of British Columbia (UBC), European Project for Ice Coring in Antarctica (EPICA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2005
• Subjects: [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; East Antarctica; Greenland; West Antarctica; Antarc*; Antarctica; ice core
• Online Access: https://insu.hal.science/insu-00374638; https://insu.hal.science/insu-00374638/document; https://insu.hal.science/insu-00374638/file/2005GL023774.pdf; https://doi.org/10.1029/2005GL023774

International audience Water isotope ratios in ice cores and marine sediments are a key indicator of past temperature and global ice volume. Quantitative interpretation of these ratios requires understanding of the storage capacity and exchanges among the ocean, atmosphere, and cryosphere. We combine numerical models of ice dynamics and tracer transport to predict bulk ice properties by simulating the fine layering of ice sheets locally validated at ice core sites. The 18O/16O content of ice sheets is found to vary between the present and 20 kyr ago from −34‰ to −37‰ for Greenland, from −41‰ to −42.5‰ for West Antarctica, and always remained near −56.5‰ for East Antarctica. Their combined effect on sea-water 18O/16O is a 0.08-0.12‰ increase 20 kyr ago, a 1.11‰ decrease if ice sheets were to vanish. We confirm that ice volume changes in Antarctica and Greenland linearly affect ocean composition, though at different rates.