 The field of climate science emerged in the second half of the twentieth century. Though it is sometimes also referred to as “climatology”, it differs markedly from the field of climatology that came before. That climatology, which existed from the late-nineteenth century (if not earlier), was an inductive science, in many ways more akin to geography than to physics; it developed systems for classifying climates based on empirical criteria and, by the mid-twentieth century, was increasingly focused on the calculation of statistics from weather observations (Nebeker 1995; Edwards 2010; Weart 2008 [2017, Other Internet Resources]; Heymann &amp; Achermann forthcoming). Climate science, by contrast, aims to explain and predict the workings of a global climate system—encompassing the atmosphere, oceans, land surface, ice sheets and more—and it makes extensive use of both theoretical knowledge and mathematical modeling. In fact, the emergence of climate science is closely linked to the rise of digital computing, which made it possible to simulate the large-scale motions of the atmosphere and oceans using fluid dynamical equations that were otherwise intractable; these motions transport mass, heat, moisture and other quantities that shape paradigmatic climate variables, such as average surface temperature and rainfall. Today, complex computer models that represent a wide range of climate system processes are a mainstay of climate research.