Stainforth, a professor at the London School of Economics, is no denier, but he asks, “What do we know with confidence bordering on certainty? How do we know it, and what is the basis for any such confidence?” His answer is that our understanding of climate change is a patchwork affair, contingent upon incomplete information that can be improved on only with more and better information. The overarching problem is that the climate is a dynamic system that has countless moving parts, each comparatively easy to measure in the singular but vexingly hard to factor in the aggregate, “the whole, huge, complex, interacting muddle of physical components from clouds to ocean ecosystems, from ice sheets to rain forests, from hurricanes to the water and carbon bound up in soils.” To follow Stainforth’s argument requires grounding in data analysis, programming, probability, statistics, and climatology. Still, the author offers some fairly accessible takeaways—e.g., we can get to work in better controlling what we can, such as reducing greenhouse gas emissions. That way lie still other moving parts, including the big social questions about what the climate future will look like: “What sort of work will be available in your nation or region? Will you be able to get the foods you want? Will you be more likely to be affected by conflict? If so, how? Will you be influenced by natural disasters and extremes? Will you be able to see relatives in far-away places?” The answers to such questions hinge on emotion, politics, and hard data, and they aren’t easy to come by in the abstract—though answer them we must.