Climate of the Past Discussions www.clim-past-discuss.net 1814-9340 1814-9359 2 4 2006 10.5194/cpd-2-605-2006 http://www.clim-past-discuss.net/2/605/2006/ http://www.clim-past-discuss.net/2/605/2006/cpd-2-605-2006.html http://www.clim-past-discuss.net/2/605/2006/cpd-2-605-2006.pdf 605 631 2006-08-23 Effect of vegetation on the Late Miocene ocean circulation G. Lohmann M. Butzin A. Micheels T. Bickert V. Mosbrugger Alfred-Wegener-Institut für Polar- und Meeresforschung, Bussestr. 24, 27570 Bremerhaven, Germany University of Bremen, P.O. Box 330440, 28334 Bremen, Germany Senckenberg Research Institute and Natural History Museum, Senckenberganlage 25, 60325 Frankfurt am Main, Germany A weak and shallow thermohaline circulation in the North Atlantic Ocean is related to an open Central American gateway and exchange with fresh Pacific waters. We estimate the effect of vegetation on the ocean general circulation using the atmospheric circulation model simulations for the Late Miocene climate. Caused by an increase in net evaporation in the Miocene North Atlantic, the North Atlantic water becomes more saline which enhances the overturning circulation and thus the northward heat transport. This effect reveals a potentially important feedback between the ocean circulation, the hydrological cycle and the land surface cover for Cenozoic climate evolution.