Simulating Miocene Warmth: Insights From an Opportunistic Multi-Model Ensemble (MioMIP1)

Pound, M.; Gasson, E.; Riihimaki, C. A.; Huber, M.; De Boer, A. M.; Sarr, A. C.; Knorr, G.; Donnadieu, Y.; von der Heydt, A. S.; Lear, C. H.; Prange, M.; Lawrence, Kira T.; Marzocchi, A.; Bradshaw, C. D.; Burls, N. J.; Lohman, G.; Frigola, A.; Zhang, Z.; Herold, N.; Farnsworth, A.; Siler, N.; Li, X.; Hutchinson, D. K.; Lunt, D. J.

Simulating Miocene Warmth: Insights From an Opportunistic Multi-Model Ensemble (MioMIP1)

Abstract

The Miocene epoch, spanning 23.03-5.33 Ma, was a dynamic climate of sustained, polar amplified warmth. Miocene atmospheric CO2 concentrations are typically reconstructed between 300 and 600 ppm and were potentially higher during the Miocene Climatic Optimum (16.75-14.5 Ma). 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 modeling 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 similar to 2 degrees C, 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 similar to 1.2 times a CO2 doubling. This study uses an ensemble of opportunity: models, boundary conditions, and reference data sets 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 toward simulating Miocene warmth while isolating remaining challenges that may be well served by community-led efforts to coordinate modeling and data activities within a common analytical framework.

Title	Simulating Miocene Warmth: Insights From an Opportunistic Multi-Model Ensemble (MioMIP1)
Creator	Pound, M.
	Gasson, E.
	Riihimaki, C. A.
	Huber, M.
	De Boer, A. M.
	Sarr, A. C.
	Knorr, G.
	Donnadieu, Y.
	von der Heydt, A. S.
	Lear, C. H.
	Prange, M.
	Lawrence, Kira T.
	Marzocchi, A.
	Bradshaw, C. D.
	Burls, N. J.
	Lohman, G.
	Frigola, A.
	Zhang, Z.
	Herold, N.
	Farnsworth, A.
	Siler, N.
	Li, X.
	Hutchinson, D. K.
	Lunt, D. J.
Publisher	Paleoceanography and Paleoclimatology
Academic Department	Geology & Environmental Geosciences
Division	Natural Sciences
Organization	Lafayette College
Date Issued	May 2021
Date Available	2021-07-14
Type	Article
Language	English
Keyword	paleoclimate
	Miocene
	Miocene surface temperature synthesis
	model intercomparison
	polar amplification
Bibliographic Citation	Burls, N. J. (2021 May) "Simulating Miocene Warmth: Insights From an Opportunistic Multi-Model Ensemble (MioMIP1)." Paleoceanography and Paleoclimatology 36 (5): e2020PA004054.
Standard Identifier	DOI 10.1029/2020PA004054
Standard Identifier	Handle 10385/pk02cc123
Permalink	http://hdl.handle.net/10385/pk02cc123
Rights Statement	Creative Commons - Attribution
Rights Holders	The Authors