Diane M. ThoMpson1, T.R. aulT1, M.n. evans2,1, J.e. Cole1,3, J. eMile-Geay4, a.n. leGRanDe5 Department of Geosciences, University of Arizona, Tucson, USA; thompsod@email.arizona.edu Department of Geology and Earth System Science Interdisciplinary Center, University of Maryland, College Park, USA; Department of Atmospheric Sciences, University of Arizona, Tucson; USA; Department of Earth Sciences, University of Southern California, Los Angeles, USA; NASA Goddard Institute for Space Studies and Center for Climate Systems Research, Columbia University, New York, USA