Thermodynamics of climate change: Generalized sensitivities
Using a recent theoretical approach, we study how global warming impacts the thermodynamics of the cli-mate system by performing experiments with a simplified yet Earth-like climate model. The intensity of the Lorenz energy cycle, the Carnot efficiency, the material entropy produc-tion, and the degree of irreversibility of the system change monotonically with the CO 2 concentration. Moreover, these quantities feature an approximately linear behaviour with re-spect to the logarithm of the CO 2 concentration in a relatively wide range. These generalized sensitivities suggest that the climate becomes less efficient, more irreversible, and fea-tures higher entropy production as it becomes warmer, with changes in the latent heat fluxes playing a predominant role. These results may be of help for explaining recent findings obtained with state of the art climate models regarding how increases in CO 2 concentration impact the vertical stratifi-cation of the tropical and extratropical atmosphere and the position of the storm tracks.