Modeling geologically abrupt climate changes in the Miocene
B. J. Haupt1 and D. Seidov21EMS Earth and Environmental Systems Institute, Pennsylvania State University, PA 16802, University Park, USA 2NOAA/NODC, Ocean Climate Laboratory, MD 20910, Silver Spring, USA
Received: 09 Nov 2010 – Accepted for review: 25 Nov 2010 – Discussion started: 14 Dec 2010
Abstract. The gradual cooling of the Cenozoic, including the Miocene epoch, was punctuated by many geologically abrupt warming and cooling episodes – strong deviations from the cooling trend with time span of ten to hundred thousands of years. Our working hypothesis is that some of those warming episodes at least partially might have been caused by dynamics of the emerging Antarctic Ice Sheet, which, in turn, might have caused strong changes of sea surface salinity in the Miocene Southern Ocean. Feasibility of this hypothesis is explored in a series of coupled ocean-atmosphere computer experiments. The results suggest that relatively small and geologically short-lived changes in freshwater balance in the Southern Ocean could have significantly contributed to at least two prominent warming episodes in the Miocene. Importantly, the experiments also suggest that the Southern Ocean was more sensitive to the salinity changes in the Miocene than today, which can attributed to the opening of the Central American Isthmus as a major difference between the Miocene and the present-day ocean-sea geometry.
Haupt, B. J. and Seidov, D.: Modeling geologically abrupt climate changes in the Miocene, Clim. Past Discuss., 6, 2687-2701, doi:10.5194/cpd-6-2687-2010, 2010.