Thermodynamics of Climate Change: Generalized Sensitivities

Using a recently developed formalism, we present an in-depth analysis of how the thermodynamics of the climate system varies with CO2 concentration by performing experiments with a simplified yet Earth-like climate model. We find that, in addition to the globally averaged surface temperature, the intensity of the Lorenz energy cycle, the Carnot efficiency, the entropy production and the degree of irreversibility of the system are linear with the logarithm of the CO2 concentration. The generalized sensitivities proposed here suggest that the climate system becomes less efficient, more irreversible, and features higher entropy production as it becomes warmer.