The Late Cretaceous continental interior of Siberia: A challenge for climate models

Geological evidence from the Late Cretaceous continental interior of the Vilui Basin, Siberia suggests a far wetter, warmer, and more equable annual climate than General Circulation Models (GCMs) can reproduce. The disparity cannot be bridged by the uncertainties inherent in either the models or the geological climate proxies. This implies the mismatch is genuine and that either 1) we have systematic errors in the interpretation/calibration of the climate proxies, and/or 2) lack of full knowledge of the boundary conditions needed for GCM models simulations of this period, and/or 3) an insufficient understanding of the nature of the coupled atmosphere–ocean–biosphere system and its representation within climate models during warm climate epochs. If it is the third explanation, this would have important implications for the prediction of future climates and would suggest that we may currently be underestimating future climate change in such regions.