title: A major advance of tropical Andean glaciers during the Antarctic cold reversal.
abstract: The Younger Dryas stadial, a cold event spanning 12,800 to 11,500 years ago, during the last deglaciation, is thought to coincide with the last major glacial re-advance in the tropical Andes. This interpretation relies mainly on cosmic-ray exposure dating of glacial deposits. Recent studies, however, have established new production rates for cosmogenic (10)Be and (3)He, which make it necessary to update all chronologies in this region and revise our understanding of cryospheric responses to climate variability. Here we present a new (10)Be moraine chronology in Colombia showing that glaciers in the northern tropical Andes expanded to a larger extent during the Antarctic cold reversal (14,500 to 12,900 years ago) than during the Younger Dryas. On the basis of a homogenized chronology of all (10)Be and (3)He moraine ages across the tropical Andes, we show that this behaviour was common to the northern and southern tropical Andes. Transient simulations with a coupled global climate model suggest that the common glacier behaviour was the result of Atlantic meridional overturning circulation variability superimposed on a deglacial increase in the atmospheric carbon dioxide concentration. During the Antarctic cold reversal, glaciers advanced primarily in response to cold sea surface temperatures over much of the Southern Hemisphere. During the Younger Dryas, however, northern tropical Andes glaciers retreated owing to abrupt regional warming in response to reduced precipitation and land-surface feedbacks triggered by a weakened Atlantic meridional overturning circulation. Conversely, glacier retreat during the Younger Dryas in the southern tropical Andes occurred as a result of progressive warming, probably influenced by an increase in atmospheric carbon dioxide. Considered with evidence from mid-latitude Andean glaciers, our results argue for a common glacier response to cold conditions in the Antarctic cold reversal exceeding that of the Younger Dryas.
authors.affiliation: Université Paris 1 Panthéon-Sorbonne, CNRS Laboratoire de Géographie Physique, 92195 Meudon, France.
authors.forename: V
authors.initials: V
authors.lastname: Jomelli
authors.affiliation: Université Grenoble Alpes, LGGE, UMR 5183, F-38041 Grenoble, France.
authors.forename: V
authors.initials: V
authors.lastname: Favier
authors.affiliation: Department of Atmospheric and Environmental Sciences, University at Albany, Albany, New York 12222, USA.
authors.forename: M
authors.initials: M
authors.lastname: Vuille
authors.affiliation: Aix-Marseille Université, CNRS-IRD-Collège de France, CEREGE UM34, 13545 Aix-en-Provence, France.
authors.forename: R
authors.initials: R
authors.lastname: Braucher
authors.affiliation: CNRS, Centre de Recherches Pétrographiques et Géochimiques, UMR 7358, Université de Lorraine, BP 20, Vandoeuvre-lès-Nancy 54501, France.
authors.forename: L
authors.initials: L
authors.lastname: Martin
authors.affiliation: CNRS, Centre de Recherches Pétrographiques et Géochimiques, UMR 7358, Université de Lorraine, BP 20, Vandoeuvre-lès-Nancy 54501, France.
authors.forename: P-H
authors.initials: PH
authors.lastname: Blard
authors.affiliation: Department of Atmospheric and Environmental Sciences, University at Albany, Albany, New York 12222, USA.
authors.forename: C
authors.initials: C
authors.lastname: Colose
authors.affiliation: Université Paris 1 Panthéon-Sorbonne, CNRS Laboratoire de Géographie Physique, 92195 Meudon, France.
authors.forename: D
authors.initials: D
authors.lastname: Brunstein
authors.affiliation: Center for Climatic Research, Nelson Institute for Environmental Studies, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: F
authors.initials: F
authors.lastname: He
authors.affiliation: IRD-Laboratoire d'Océanographie et du Climat: Expérimentation et Approche numérique, Université Pierre et Marie Curie, F-75252 Paris Cedex 05, France.
authors.forename: M
authors.initials: M
authors.lastname: Khodri
authors.affiliation: Aix-Marseille Université, CNRS-IRD-Collège de France, CEREGE UM34, 13545 Aix-en-Provence, France.
authors.forename: D L
authors.initials: DL
authors.lastname: Bourlès
authors.affiliation: Aix-Marseille Université, CNRS-IRD-Collège de France, CEREGE UM34, 13545 Aix-en-Provence, France.
authors.forename: L
authors.initials: L
authors.lastname: Leanni
authors.affiliation: School of Geography and Geosciences Irvine Building, University of St Andrews, St Andrews KY16 9AL, UK.
authors.forename: V
authors.initials: V
authors.lastname: Rinterknecht
authors.affiliation: Université Paris 1 Panthéon-Sorbonne, CNRS Laboratoire de Géographie Physique, 92195 Meudon, France.
authors.forename: D
authors.initials: D
authors.lastname: Grancher
authors.affiliation: Institut de Recherche pour le Développement, CP 9214, La Paz, Bolivia.
authors.forename: B
authors.initials: B
authors.lastname: Francou
authors.affiliation: Institute for Hydrology, Meteorology and Environmental Studies, Bogota, 07603, Colombia.
authors.forename: J L
authors.initials: JL
authors.lastname: Ceballos
authors.affiliation: Escuela de Ingeniería Geológica, UPTC Sede Seccional Sogamoso, Sogamoso, 152211, Colombia.
authors.forename: H
authors.initials: H
authors.lastname: Fonseca
authors.affiliation: Center for Climatic Research and Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Climate and Global Dynamics Division, National Center for Atmospheric Research, Boulder, Colorado 80305, USA.
authors.forename: B L
authors.initials: BL
authors.lastname: Otto-Bliesner
mesh_terms: D001608:Beryllium / Q000032:analysis; D002980:Climate; D003080:Cold Temperature; D003105:Colombia; D006371:Helium / Q000032:analysis; D046448:Ice Cover; D007554:Isotopes / Q000032:analysis
chemical_list: D007554:Isotopes; D006371:Helium; D001608:Beryllium