It’s important to keep in mind that we’re talking about climate here, not weather. The object is not to predict what temperature it will be in Delhi on, say, March 5, 2023, or exactly when the next hurricane will hit New Orleans. Instead, we want to predict the trend in the climate over the coming decades. Like modeling weather, this, too, is no easy task. Climate models have to account for interactions between the land surface, ice, oceans, the sun, and the atmosphere, among other factors. What’s remarkable is that despite their complexity, climate models do an impressively good job, as we’ll explain, and are improving all the time.