AbstractModeling is a central concept, a central tool in climate research. Models are telling us how the future may develop in the next 100 years, the public is told by some experts, while others insist that all such perspectives rest on shaky mathematical constructs with little connection to reality. This confusion has much to do with different epistemological cultures in different quarters of science and among the public at large. The word “model” simply means quite different concepts. These range from process-based dynamical models—which serve as a kind of substitute reality in meteorology, oceanography, and climate science—to pre-forms of theory in physics or to mechanical analogs in engineering or in public education.1 To overcome this confusion requires an appropriate explanation what this term “modeling” usually implies in the field of climate science.