JpGU-AGU Joint Meeting 2020

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[E] Oral

U (Union ) » Union

[U-05] Advanced understanding of Quaternary and Anthropocene hydroclimate changes in East Asia

convener:Chuan-Chou Shen(High-Precision Mass Spectrometry and Environment Change Laboratory, Department of Geosciences, National Taiwan University), Yusuke Yokoyama(Atmosphere and Ocean Research Institute, University of Tokyo), Kaoru Kubota(Graduate School of Human Development and Environment, Kobe University), Li Lo(Department of Geosciences, National Taiwan University), Chairperson:Chuan-Chou Shen(High-Precision Mass Spectrometry and Environment Change Laboratory, Department of Geosciences, National Taiwan University), Chairperson:Yusuke Yokoyama(Atmosphere and Ocean Research Institute, University of Tokyo), Chairperson:Kaoru Kubota(Kochi Institute for Core Sample Research, JAMSTEC), Chairperson:Li Lo(Department of Geosciences, National Taiwan University)

[U05-02] Late-Holocene anthropogenic impact on tropical climate

★Invited Papers

*Yair Rosenthal1, Samantha Claudia Bova1, Zhengyu Liu2, Mi Yan3 (1.Rutgers University, 2.Ohio State University, 3.Nanjing Normal University)

Keywords:Quaternary, Holocene, tropics

Climate models indicate that rising preindustrial greenhouse gas (GHG) levels since 7 ka caused increase in mean annual temperatures (MAT) comparable to that observed since the industrial revolution. However, geochemical temperature proxies offer inconsistent evidence, which was termed “The Holocene Conundrum”. Specifically, Mg/Ca records in planktonic foraminifera from the Western Pacific warm pool (WPWP) record cooling in direct opposition to alkenone derived temperature records from the South China Sea and to simulated trends. Here, we present a new, centennially resolved record of planktic foraminifer (G. ruber ss) Mg/Ca-derived sea surface temperatures (SSTs) spanning the currentand last interglacial (LIG) periods from the WPWP and compare these data to two transient climate simulations. Taking advantage of a stronger seasonal contrast during the LIG, we demonstrate that Mg/Ca-derived SSTs reflect late Fall SSTs, rather than mean annual. Applying this seasonal relationship to the Holocene, we reconcile the proxy record with model output, assess the WPWP SST sensitivity to GHGs, and ultimately confirm that preindustrial warming has doubled the anthropogenic total. We will also examine possible effects on precipitation in the Western Pacific warm pool.