1Department of Meteorology, University of Reading, Earley Gate, P.O. Box 243, Reading RG6 6BB, UK
2Department of Mathematics, University of Reading, Whiteknights, P.O. Box 220, Reading RG6 6AX, UK
3Department of Physics, University of Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy
4Meteorologisches Institut, Klima Campus, University of Hamburg, Grindelberg 5, 20144 Hamburg, Germany
Abstract. Using a recent theoretical approach, we study how the impact of global warming of the thermodynamics of the climate system by performing experiments with a simplified yet Earth-like climate model. In addition to the globally averaged surface temperature, the intensity of the Lorenz energy cycle, the Carnot efficiency, the material entropy production and the degree of irreversibility of the system are linear with the logarithm of the CO2 concentration. These generalized sensitivities suggest that the climate becomes less efficient, more irreversible, and features higher entropy production as it becomes warmer.