Persistent near--tropical warmth on the Antarctic continent

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TitlePersistent near-tropical warmth on the Antarctic continent during the early Eocene epochAbstractThe warmest global climates of the past 65 million years occurred during the early Eocene epoch (about 55 to 48 million years ago), when the Equator--to--pole temperature gradients were much smaller than today and atmospheric carbon dioxide levels were in excess of one thousand parts per million by volume. Recently the early Eocene has received considerable interest because it may provide insight into the response of EarthÅ› climate and biosphere to the high atmospheric carbon dioxide levels that are expected in the near future as a consequence of unabated anthropogenic carbon emissions. Climatic conditions of the early Eocene `greenhouse world,Ì however, are poorly constrained in critical regions, particularly Antarctica. Here we present a well--dated record of early Eocene climate on Antarctica from an ocean sediment core recovered off the Wilkes Land coast of East Antarctica. The information from biotic climate proxies (pollen and spores) and independent organic geochemical climate proxies (indices based on branched tetraether lipids) yields quantitative, seasonal temperature reconstructions for the early Eocene greenhouse world on Antarctica. We show that the climate in lowland settings along the Wilkes Land coast (at a palaeolatitude of about 70^circ south) supported the growth of highly diverse, near-tropical forests characterized by mesothermal to megathermal floral elements including palms and Bombacoideae. Notably, winters were extremely mild (warmer than 10^circC) and essentially frost--free despite polar darkness, which provides a critical new constraint for the validation of climate models and for understanding the response of high--latitude terrestrial ecosystems to increased carbon dioxide forcing. â"' 2012 Macmillan Publishers Limited. All rights reserved.AcknowledgementsThis research used samples and data provided by the Integrated Ocean Drilling Program (IODP). The IODP is sponsored by the US National Science Foundation and participating countries under the management of Joint Oceanographic Institutions, Inc. Financial support for this research was provided by the German Research Foundation, to J.P. (grant PR 651/10) and U.R. (grant RO 1113/6); the Biodiversity and Climate Research Center of the Hessian Initiative for Scientific and Economic Excellence, to J.P.; the Netherlands Organisation for Scientific Research, to H.B. and S.S. (VICI grant); the Natural Sciences and Engineering Research Council of Canada, to D.R.G. (grant DG 311934); the Natural Environment Research Council, to S.M.B. (grant Ne/J019801/1), J.A.B. (grant Ne/I00646X/1) and T.v.d.F. (grant Ne/I006257/1); the US National Science Foundation, to L.T. (grant OCE 1058858); and the New Zealand Ministry of Science and Innovation, to J.I.R.. We thank J. Francis, S. Gollner and M. Huber for discussions, and B. Coles, E. Hopmans, K. Kreissig, A. Mets, J. Ossebaar, B. Schminke, J. Treehorn and N. Welters for technical support.

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1st AuthorPross, J.AuthorPross, J.Contreras, L.Bijl, P.Greenwood, D.Bohaty, S.Schouten, S.Bendle, J.Röhl, U.Tauxe, L.Raine, J.Huck, C.Van De Flierdt, T.Jamieson, S.Stickley, C.Van De Schootbrugge, B.Escutia, C.Brinkhuis, H.Brinkhuis, H.Escutia Dotti, C.Klaus, A.Fehr, A.Williams, T.Bendle, J.Bijl, P.Bohaty, S.Carr, S.Dunbar, R.Gonzalez, J.Hayden, T.Iwai, M.Jimenez Espejo, F.Katsuki, K.Soo Kong, G.Mc Kay, R.Nakai, M.Olney, M.Passchier, S.Pekar, S.Pross, J.Riesselman, C.Röhl, U.Sakai, T.Shrivastava, P.Stickley, C.Sugisaki, S.Tauxe, L.Tuo, S.Van De Flierdt, T.Welsh, K.Yamane, M.Year2012JournalNatureVolume488Number7409Pages73-77DOI10.1038/nature11300URLhttps://www.scopus.com/inward/recor.....8bd1516e8694ad9491d573fb9Keywordscarbon dioxidelipid, animalAntarcticaarticleatmospherebacterial sporecell respirationchemistryecosystemgreenhouse effectgrowth, development and aginghistoryhuman activitiesisolation and purificationphotosynthesispollenreproducibilityseasonsedimenttemperaturetheoretical modeltreetropic climateAntarcticaBombacoideaechemical compositionenvironmental temperatureEocenefloraforestglobal climategreenhousepalmplantpriority journalquantitative analysisseaspore germinationwinter, AnimalsAntarctic RegionsAtmosphereCarbon DioxideCell RespirationEcosystemGeologic SedimentsGreenhouse EffectHistory, AncientHuman ActivitiesLipidsModels, TheoreticalPhotosynthesisPollenReproducibility of ResultsSeasonsSporesTemperatureTreesTropical Climate, carbon dioxidecarbon emissionclimate conditionsclimate modelingEoceneglobal climatelatitudemarine sedimentmonocotyledonpaleolatitudepollenproxy climate recordreconstructionsediment coretemperature gradientterrestrial ecosystemtropical foresttropical region, AntarcticaEast AntarcticaWilkes Land, Bombacoideae, rank1

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TypeArticleCitationPross, J.Contreras, L.Bijl, P.Greenwood, D.Bohaty, S.Schouten, S.Bendle, J.Röhl, U.Tauxe, L.Raine, J.Huck, C.Van De Flierdt, T.Jamieson, S.Stickley, C.Van De Schootbrugge, B.Escutia, C.Brinkhuis, H.Brinkhuis, H.Escutia Dotti, C.Klaus, A.Fehr, A.Williams, T.Bendle, J.Bijl, P.Bohaty, S.Carr, S.Dunbar, R.Gonzalez, J.Hayden, T.Iwai, M.Jimenez Espejo, F.Katsuki, K.Soo Kong, G.Mc Kay, R.Nakai, M.Olney, M.Passchier, S.Pekar, S.Pross, J.Riesselman, C.Röhl, U.Sakai, T.Shrivastava, P.Stickley, C.Sugisaki, S.Tauxe, L.Tuo, S.Van De Flierdt, T.Welsh, K.Yamane, M. (2012). Persistent near-tropical warmth on the Antarctic continent during the early Eocene epoch. Nature. 448(7409): 73-77IdentifierPross2012Relevancerank1