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Clim. Past Discuss., 7, 241-304, 2011
www.clim-past-discuss.net/7/241/2011/ doi:10.5194/cpd-7-241-2011 © Author(s) 2011. This work is distributed under the Creative Commons Attribution 3.0 License. |
The early Eocene equable climate problem revisited
1Earth and Atmospheric Sciences Department, Purdue University, West Lafayette, Indiana, USA
2Meteorology and Climate Centre, School of Mathematical Sciences, University College Dublin, Dublin, Ireland
Abstract. The early Eocene "equable climate problem", i.e. warm extratropical annual mean and above-freezing winter temperatures evidenced by proxy records, has remained as one of the great unsolved problems in paleoclimate. Recent progress in modeling and in paleoclimate proxy development provides an opportunity to revisit this problem to ascertain if the current generation of models can reproduce the past climate features without extensive modification. Here we have compiled early Eocene terrestrial temperature data and compared with climate model results with a consistent and rigorous methodology. We test the hypothesis that equable climates can be explained simply as a response to increased greenhouse gas forcing within the framework of the atmospheric component of the Community Climate System Model (version 3), a climate model in common use for predicting future climate change. We find that, with suitably large radiative forcing, the model and data are in general agreement for annual mean and cold month mean temperatures, and that the pattern of high latitude amplification recorded by proxies can be reproduced.
Citation: Huber, M. and Caballero, R.: The early Eocene equable climate problem revisited, Clim. Past Discuss., 7, 241-304, doi:10.5194/cpd-7-241-2011, 2011.