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Simulating Miocene warmth: insights from an opportunistic Multi-Model ensemble (MioMIP1)
  • +21
  • Natalie J Burls,
  • Catherine Bradshaw,
  • Agatha Margaretha De Boer,
  • Nicholas Herold,
  • Matthew Huber,
  • Matthew Pound,
  • Yannick Donnadieu,
  • Alexander Farnsworth,
  • Amanda Frigola Boix,
  • Edward G. W. Gasson,
  • Anna von der Heydt,
  • David Karel Hutchinson,
  • Gregor Knorr,
  • Kira T Lawrence,
  • Caroline H. Lear,
  • Xiangyu Li,
  • Gerrit Lohmann,
  • Daniel J. Lunt,
  • Alice Marzocchi,
  • Matthias Prange,
  • Catherine Anne Riihimaki,
  • Anta-Clarisse Sarr,
  • Nicholas Siler,
  • Zhongshi Zhang
Natalie J Burls
George Mason University

Corresponding Author:[email protected]

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Catherine Bradshaw
Exeter University
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Agatha Margaretha De Boer
Stockholm University
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Nicholas Herold
University of New South Wales
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Matthew Huber
Purdue University
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Matthew Pound
Northumbria University
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Yannick Donnadieu
CEREGE (Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement)
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Alexander Farnsworth
University of Bristol
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Amanda Frigola Boix
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Edward G. W. Gasson
University of Bristol
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Anna von der Heydt
Universiteit Utrecht, Utrecht
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David Karel Hutchinson
Stockholm University
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Gregor Knorr
AWI Bremerhaven
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Kira T Lawrence
Lafayette College
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Caroline H. Lear
Cardiff University
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Xiangyu Li
Institute of Atmospheric Physics, Chinese Academy of Sciences
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Gerrit Lohmann
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Daniel J. Lunt
University of Bristol
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Alice Marzocchi
National Oceanography Centre
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Matthias Prange
MARUM - Zentrum für Marine Umweltwissenschaften
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Catherine Anne Riihimaki
Princeton University
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Anta-Clarisse Sarr
Aix Marseille Univ, CNRS, IRD, Coll France, INRA, CEREGE
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Nicholas Siler
Oregon State University
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Zhongshi Zhang
China University of Geoscience, Wuhan
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The Miocene epoch, spanning 23.03-5.33Ma, was a dynamic climate of sustained, polar amplified warmth. Miocene atmospheric CO2 concentrations are typically reconstructed between 300-600ppm and were potentially higher during the Miocene Climatic Optimum (16.75-14.5Ma). With surface temperature reconstructions pointing to substantial midlatitude and polar warmth, it is unclear what processes maintained the much weaker-than-modern equator-to-pole temperature difference. Here we synthesize several Miocene climate modeling efforts together with available terrestrial and ocean surface temperature reconstructions. We evaluate the range of model-data agreement, highlight robust mechanisms operating across Miocene modelling efforts, and regions where differences across experiments result in a large spread in warming responses. Prescribed CO2 is the primary factor controlling global warming across the ensemble. On average, elements other than CO2, such as Miocene paleogeography and ice sheets, raise global mean temperature by ~ 2℃, with the spread in warming under a given CO2 concentration (due to a combination of the spread in imposed boundary conditions and climate feedback strengths) equivalent to ~1.2 times a CO2 doubling. This study uses an ensemble of opportunity: models, boundary conditions, and reference datasets represent the state-of-art for the Miocene, but are inhomogeneous and not ideal for a formal intermodel comparison effort. Acknowledging this caveat, this study is nevertheless the first Miocene multi-model, multi-proxy comparison attempted so far. This study serves to take stock of the current progress towards simulating Miocene warmth while isolating remaining challenges that may be well served by community-led efforts to coordinate modelling and data activities within a common analysis framework.