Large-scale features of Pliocene climate: results from the Pliocene Model Intercomparison Project

• DOI: 10.5194/cp-9-191-2013
• Publication Date: 2013-01-25T13:04:06Z
• Authors: A. M. Haywood; D. J. Hill; A. M. Dolan; B. L. Otto-Bliesner; F. Bragg; W.-L. Chan; M. A. Chandler; C. Contoux; H. J. Dowsett; A. Jost; Y. Kamae; G. Lohmann; D. J. Lunt; A. Abe-Ouchi; S. J. Pickering; G. Ramstein; N. A. Rosenbloom; U. Salzmann; L. Sohl; C. Stepanek; H. Ueda; Q. Yan; Z. Zhang
• Keywords: Earth system science; Proxy (statistics); Forcing (mathematics); Paleoclimatology; Palaeogeography; Climate system

Abstract. Climate and environments of the mid-Pliocene warm period (3.264 to 3.025 Ma) have been extensively studied. Whilst numerical models shed light on nature climate at time, uncertainties in their predictions not systematically examined. The Pliocene Model Intercomparison Project quantifies model outputs through a coordinated multi-model multi-model/data intercomparison. commonalities for are clearly evident, we show substantial variation sensitivity implementation boundary conditions. Models appear able reproduce many regional changes temperature reconstructed from geological proxies. However, data/model comparison highlights that potentially underestimate polar amplification. To assert this conclusion with greater confidence, limitations time-averaged proxy data currently available must be addressed. Furthermore, tests exploring known unknowns modelling specifically relevant high latitudes essential (e.g. palaeogeography, gateways, orbital forcing trace gasses). Estimates longer-term CO2 (also as Earth System Sensitivity; ESS), support previous work suggesting ESS is than Sensitivity (CS), suggest ratio CS between 1 2, "best" estimate 1.5.