PP007-07
Simulating Miocene warmth: insights from an opportunistic Multi-Model ensemble (MioMIP1)
Monday, 7 December 2020: 10:54
Virtual
Natalie Burls1, Catherine Bradshaw2, Agatha M De Boer3, Nicholas Herold4, Matt Huber5, Matthew J Pound6, Yannick Donnadieu7, Alexander Farnsworth8, Amanda Frigola9, Edward Gasson10, Anna S von der Heydt11, David Hutchinson3, Gregor Knorr12, Kira T Lawrence13, Caroline H Lear14, Xiangyu Li15, Gerrit Lohmann16, Dan John Lunt17, Alice Marzocchi18, Matthias Prange19, Catherine A Riihimaki20, Anta-Clarisse Sarr21, Nicholas Siler22 and Zhongshi Zhang23, (1)George Mason University Fairfax, Department of Atmospheric, Oceanic & Earth Sciences, Fairfax, VA, United States, (2)Met Office Hadley Centre, Exeter, United Kingdom, (3)Stockholm University, Stockholm, Sweden, (4)The NSW Department of Planning, Industry and Environment, Science Division, Climate and Atmospheric Science, Sydney, NSW, Australia, (5)Purdue University, Department of Earth, Atmospheric and Planetary Sciences, West Lafayette, IN, United States, (6)Northumbria University, Geography, Newcastle-Upon-Tyne, United Kingdom, (7)Aix-Marseille University, CNRS, IRD, Coll. France, Cerege, Aix-en-Provence, France, (8)University of Bristol, BRIDGE, School of Geographical Sciences, Bristol, United Kingdom, (9)Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany, (10)University of Bristol, Bristol, United Kingdom, (11)Utrecht University, Utrecht, Netherlands, (12)Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research Bremerhaven, Bremerhaven, Germany, (13)Lafayette College, Geology and Environmental Geosciences Department, Easton, PA, United States, (14)Cardiff University, School of Earth and Ocean Sciences, Cardiff, United Kingdom, (15)Department of Atmospheric Science, School of Environmental studies, China University of Geoscience, Wuhan, China, (16)Alfred Wegener Institute for P, Bremerhaven, Germany, (17)University of Bristol, Bristol, BS8, United Kingdom, (18)National Oceanography Centre, Southampton, United Kingdom, (19)MARUM - University of Bremen, Bremen, Germany, (20)Princeton University, Princeton, NJ, United States, (21)Aix Marseille Univ, CNRS, IRD, INRA, Coll France, CEREGE, Aix-en-Provence, France, Aix en Provence, France, (22)Oregon State University, Corvallis, OR, United States, (23)Bjerknes Centre for Climate Research, Bergen, Norway
Abstract:
The Miocene epoch, spanning 23.03-5.33Ma, was a dynamic climate of sustained, polar amplified warmth, characterized by sea ice-free winters in the Arctic during the warmest phases, and substantial fluctuations in the Antarctic ice sheet. 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 this much weaker-than-modern equator-to-pole temperature gradient. Here we synthesize several climate modeling efforts, together with available terrestrial and ocean surface temperature reconstructions. We evaluate the current range of model-data agreement, highlight robust mechanisms operating across Miocene modelling efforts, as well as the regions where the differences across models (coming from a combination of model differences in imposed non-CO2 Miocene boundary conditions and model feedback strengths) result in a large spread in warming responses. This is an ensemble of opportunity: the models, boundary conditions, and reference datasets are state-of-the-art, but also inhomogeneous and not ideal for a formal intermodel comparison effort. Acknowledging this caveat, this study is nevertheless the first multi-model, multi-proxy comparison for the Miocene 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-lead efforts to coordinate modelling and data activities within a common analysis framework.
