Subfossil trees suggest enhanced Mediterranean hydroclimate variability at the onset of the Younger Dryas

• Published in: Scientific Reports
• Main Authors: Pauly, Maren, Helle, Gerhard, Miramont, Cécile, Büntgen, Ulf, Treydte, Kerstin, Reinig, Frederick, Guibal, Frédéric, Sivan, Olivier, Heinrich, Ingo, Riedel, Frank, Kromer, Bernd, Balanzategui, Daniel, Wacker, Lukas, Sookdeo, Adam, Brauer, Achim
• Other Authors: German Research Centre for Geosciences - Helmholtz-Centre Potsdam (GFZ), Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement IRD : UMR237-Centre National de la Recherche Scientifique (CNRS), Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Culture et Environnements, Préhistoire, Antiquité, Moyen-Age (CEPAM), Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Nice Sophia Antipolis (. - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Institut national de recherches archéologiques préventives (Inrap), University of Johannesburg (UJ), Institute of Environmental Physics Heidelberg (IUP), Universität Heidelberg Heidelberg, Institute for Particle Physics and Astrophysics ETH Zürich (IPA), Department of Physics ETH Zürich (D-PHYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology Zürich (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology Zürich (ETH Zürich), GeoForschungsZentrum - Helmholtz-Zentrum Potsdam (GFZ)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: Palaeoclimate; Geochemistry; Atmospheric chemistry; envir; geo; Greenland; Greenland ice core; ice core; NGRIP; North Atlantic; Sea ice
• Online Access: https://doi.org/10.1038/s41598-018-32251-2; https://hal-amu.archives-ouvertes.fr/hal-01884902/file/Pauly%20et%20al%20Nature%20Scientific%20Reports%202018.pdf; https://hal-amu.archives-ouvertes.fr/hal-01884902

International audience Nearly 13,000 years ago, the warming trend into the Holocene was sharply interrupted by a reversal to near glacial conditions. Climatic causes and ecological consequences of the Younger Dryas (YD) have been extensively studied, however proxy archives from the Mediterranean basin capturing this period are scarce and do not provide annual resolution. Here, we report a hydroclimatic reconstruction from stable isotopes (δ 18 O, δ 13 C) in subfossil pines from southern France. Growing before and during the transition period into the YD (12 900-12 600 cal BP), the trees provide an annually resolved, continuous sequence of atmospheric change. Isotopic signature of tree sourcewater (δ 18 O sw) and estimates of relative air humidity were reconstructed as a proxy for variations in air mass origin and precipitation regime. We find a distinct increase in inter-annual variability of sourcewater isotopes (δ 18 O sw), with three major downturn phases of increasing magnitude beginning at 12 740 cal BP. The observed variation most likely results from an amplified intensity of North Atlantic (low δ 18 O sw) versus Mediterranean (high δ 18 O sw) precipitation. This marked pattern of climate variability is not seen in records from higher latitudes and is likely a consequence of atmospheric circulation oscillations at the margin of the southward moving polar front. During the abrupt and intense climate change from the Allerød warm phase to the YD cold reversal in the North Hemisphere (ca. 12 700-11 600 cal BP) 1,2 sea-ice production and drifting enhanced 3 , alpine glaciers advanced 4 , storm intensity strengthened 5 , and a reorganization of the atmosphere 6,7 may have occurred. Greenland ice core data (NGRIP) reveal temperature drops of 10-15 °C with simultaneous reductions in snow accumulation and amplifications in atmospheric dust within less than a decade 6,8. During the rapid cooling, lake sediment records across Europe signal intensified wind stress, aridity and detrital input, alongside drastic ...