Permian climates: Evaluating model predictions using global paleobotanicaldata

The most recent global icehouse-hothouse climate transition in Earth histor y occurred in the Permian. Warmer polar conditions relative to today existe d from the middle Permian through the Mesozoic and into the Cenozoic. We fo cus here on one particularly well-correlated middle Permian stage that post dated the deglaciation, the Wordian (267-264 Ma), integrating floral and li thological data to determine Wordian climates globally. Paleobotanical data provide the best means of interpreting terrestrial paleoclimates, often re vealing important information in the continuum between "dry" and "wet" end- member lithological indicators such as evaporites and coals. New statistica l analyses of Wordian floras worldwide have enabled a greater understanding of original vegetation patterns and prevailing climate conditions. The der ived climate interpretations are compared with new Wordian atmospheric gene ral circulation model simulations. The model matches the data well in the t ropics and northern high latitudes, but predicts colder conditions in south ern high latitudes. We discuss possible reasons for this discrepancy.