Practical Philosophies of Climate Modeling

Gavin Schmidt (National Aeronautics and Space Administration (NASA), Goddard Institute for Space Studies (GISS))


Abstract: I give an overview of the practice of developing and using complex climate models, as seen from experiences in a major US center for climate sci – ence and through participation in the Coupled Model Intercomparison Project (CMIP). I’ll discuss the construction and calibration of models; their evalua – tion, especially through use of out-of-sample tests; and their exploitation in multi-model ensembles to identify biases and make predictions. The frame – work used for making inferences about reality using simulations is naturally Bayesian (in an informal sense), and has many points of contact with more familiar examples of scientific epistemology. While the use of complex simula – tions in science is a development that changes much in how science is done in practice, I argue that the concepts being applied fit very much into traditional practices of the scientific method, and indeed, illuminate them clearly.