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near the equator receive more energy, and the incoming energy drops off as we move north or south toward the poles. Alternatively, if we are interested in differences in radiation received by different levels of the atmosphere, we might implement a one-dimensional model that’s organized vertically, rather than horizontally. Even more detailed models combine these approaches: two-dimensional models account for variation in incoming solar energy as a function of both height and latitude.

Energy balance models, though, are fundamentally limited by their focus on radiation as the only interesting factor driving the state of the climate. While the radiative forcing of the sun (and the action of greenhouse gasses in the presence of that radiative forcing) is certainly one of the dominant factors influencing the dynamics of the Earth’s climate, it is equally certainly not the only such factor. If we want to attend to other factors, we need to supplement energy balance models with models of a fundamentally different character, not just create increasingly sophisticated energy balance models. McGuffie & Herderson-Sellers (2005) list five different components that need to be considered if we’re to get a full picture of the climate: radiation, dynamics, surface processes, chemistry, and spatio-temporal resolution.[1] While I will eventually argue that this list is incomplete, it serves as a very good starting point for consideration of the myriad of climate models living in the wild today.

Radiation concerns the sort of processes that are capture by energy balance models: the transfer of energy from the sun to the Earth, and the release of energy back into space (in the form of infrared radiation) from the Earth. As we’ve seen, careful attention to this factor can produce a model that is serviceable for some purposes, but which is limited in scope. In

  1. McGuffie & Herderson-Sellers (2005), p. 49