A favorite rhetorical tactic of global warming skeptics is to point out that climate scientists use models, which they imply are less scientific than the hard data used by other disciplines. This is, on its face, dumb. Every scientific field uses data to develop models, uses models to predict future data, and where there are discrepancies modifies either the data collection methods the models (or both). Climate science does the same. There are, however, interesting and unique features of climate models, and the indispensable RealClimate offers a quick synopsis thereof. It’s slightly technical, but good reading nonetheless.