Thermodynamics of climate change: generalized sensitivities

V Lucarini,K Fraedrich,F Lunkeit

doi:10.5194/acp-10-9729-2010

V Lucarini, K Fraedrich + Show 1 more

Open Access

https://doi.org/10.5194/acp-10-9729-2010

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Abstract

Abstract. Using a recent theoretical approach, we study how global warming impacts the thermodynamics of the climate 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 production, and the degree of irreversibility of the system change monotonically with the CO2 concentration. Moreover, these quantities feature an approximately linear behaviour with respect to the logarithm of the CO2 concentration in a relatively wide range. These generalized sensitivities suggest that the climate becomes less efficient, more irreversible, and features 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 CO2 concentration impact the vertical stratification of the tropical and extratropical atmosphere and the position of the storm tracks.

Highlights

The most basic way to characterize the climate system is describing it as a non-equilibrium thermodynamic system, generating entropy by irreversible processes and – if timedependent forcings can be neglected – keeping a steady state by balancing the input and output of energy and entropy with the surrounding environment.A primary goal of climate science is to understand how the statistical properties of the climate system change as a result of variations in the value of external or internal parameters
As TS is almost linear with respect to the logarithm of the CO2 concentration on a large range, it is easy to generalize the definition of TS as the impact on TS of CO2 doubling so that TS = dTS d log2 [CO2]ppm
In order to fully characterize the non-equilibrium properties of the climate system, we have analysed the most important thermodynamic variables of the system introduced in the previous section:

Summary

Introduction

The most basic way to characterize the climate system is describing it as a non-equilibrium thermodynamic system, generating entropy by irreversible processes and – if timedependent forcings can be neglected – keeping a steady state by balancing the input and output of energy and entropy with the surrounding environment.A primary goal of climate science is to understand how the statistical properties of the climate system change as a result of variations in the value of external or internal parameters. The most basic way to characterize the climate system is describing it as a non-equilibrium thermodynamic system, generating entropy by irreversible processes and – if timedependent forcings can be neglected – keeping a steady state by balancing the input and output of energy and entropy with the surrounding environment. Rigorous mathematical foundations to this problem can be traced to the Ruelle response theory for non equilibrium steady state systems (Ruelle, 1998, 2009). Such an approach has been recently proved to have formal analogies with the usual Kubo response theory for quasi-equilibrium systems (Lucarini, 2008a) and to be amenable to numerical investigation (Lucarini, 2009a).

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