Articles | Volume 9, issue 4
Clim. Past, 9, 1495–1504, 2013

Special issue: Progress in paleoclimate modelling

Clim. Past, 9, 1495–1504, 2013

Research article 15 Jul 2013

Research article | 15 Jul 2013

Mid-pliocene Atlantic Meridional Overturning Circulation not unlike modern

Z.-S. Zhang3,2,1, K. H. Nisancioglu4,2,1, M. A. Chandler5, A. M. Haywood6, B. L. Otto-Bliesner7, G. Ramstein8, C. Stepanek9, A. Abe-Ouchi11,10, W.-L. Chan10, F. J. Bragg12, C. Contoux9,13, A. M. Dolan6, D. J. Hill6,14, A. Jost13, Y. Kamae15, G. Lohmann9,16, D. J. Lunt11, N. A. Rosenbloom7, L. E. Sohl5, and H. Ueda15 Z.-S. Zhang et al.
  • 1UNI Research, Allegaten 55, 5007 Bergen, Norway
  • 2Bjerknes Centre for Climate Research, Allegaten 55, 5007 Bergen, Norway
  • 3Nansen-Zhu International Research Center, Institute of Atmospheric Physics, Chinese Academy of Sciences, 100029, Beijing, China
  • 4Department of Earth Science, University of Bergen, Allegaten 41, 5007 Bergen, Norway
  • 5CCSR/GISS, Columbia University, Columbia, New York, USA
  • 6School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds, S29JT, UK
  • 7National Center for Atmospheric Research, Boulder, Colorado, USA
  • 8LSCE/IPSL, CNRS-CEA-UVSQ, Saclay, France
  • 9Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
  • 10Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Japan
  • 11Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan
  • 12BRIDGE, School of Geographical Sciences, University of Bristol, University Road, Bristol, BS8 1SS, UK
  • 13Sisyphe, CNRS/UPMC Univ Paris 06, Paris, France
  • 14British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK
  • 15Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
  • 16Institute for Environmental Physics, University of Bremen, Bremen, Germany

Abstract. In the Pliocene Model Intercomparison Project (PlioMIP), eight state-of-the-art coupled climate models have simulated the mid-Pliocene warm period (mPWP, 3.264 to 3.025 Ma). Here, we compare the Atlantic Meridional Overturning Circulation (AMOC), northward ocean heat transport and ocean stratification simulated with these models. None of the models participating in PlioMIP simulates a strong mid-Pliocene AMOC as suggested by earlier proxy studies. Rather, there is no consistent increase in AMOC maximum among the PlioMIP models. The only consistent change in AMOC is a shoaling of the overturning cell in the Atlantic, and a reduced influence of North Atlantic Deep Water (NADW) at depth in the basin. Furthermore, the simulated mid-Pliocene Atlantic northward heat transport is similar to the pre-industrial. These simulations demonstrate that the reconstructed high-latitude mid-Pliocene warming can not be explained as a direct response to an intensification of AMOC and concomitant increase in northward ocean heat transport by the Atlantic.