Climate of the Past Discussions www.clim-past-discuss.net 1814-9340 1814-9359 3 3 2007 10.5194/cpd-3-771-2007 http://www.clim-past-discuss.net/3/771/2007/ http://www.clim-past-discuss.net/3/771/2007/cpd-3-771-2007.html http://www.clim-past-discuss.net/3/771/2007/cpd-3-771-2007.pdf 771 789 2007-05-15 Tropical cooling and the onset of North American glaciation P. Huybers phuybers@fas.harvard.edu P. Molnar Department of Earth and Planetary Sciences, Harvard University, Cambridge MA, USA Department of Geological Sciences and Cooperative Institute for Research in Environmental Science, University of Colorado, Boulder CO, USA We offer a test of the idea that gradual cooling in the eastern tropical Pacific led to cooling of North America and the initiation of glaciation ~3 Myr ago. Using modern climate data we estimate how warming of the eastern tropical Pacific affects North American temperature and ice-ablation. 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