People who write about climate change are accustomed to getting emails explaining why they are mistaken. The writer, often a retired engineer, sends a couple of pages of equations “proving” that adding carbon dioxide gas (CO2) to the atmosphere cannot cause global warming. Is there a simple physics model that shows in a transparent way how humanity’s emissions of gases do heat the planet? History offers an instructive approach to this question. When scientists attacked the problem, what mental obstacles did they encounter, and how were those overcome? Two centuries of effort, summarized below, concluded that greenhouse calculations require computer models far too complex to be understood intuitively—but simple, readily grasped observations show that the models’ conclusions are plausible.
The struggle began in 1824 when Joseph Fourier, as a minor aside from his landmark contributions to the physics and mathematics of heat flow, published a speculation. He proposed...