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要旨:
Planet Earth is a thermodynamic system far from equilibrium and its
functioning—obviously—obeys the second law of thermodynamics, at the detailed
level of processes, but also at the planetary scale of the whole system. Here, we
describe the dynamics of the Earth system as the consequence of sequences of
energy conversions that are constrained by thermodynamics. We first describe the
well-established Carnot limit and show how it results in a maximum power limit
when interactions with the boundary conditions are being allowed for. To
understand how the dynamics within a system can achieve this limit, we then
explore with a simple model how different configurations of flow structures are
associated with different intensities of dissipation. When the generation of power
and these different configuration of flow structures are combined, one can associate
the dynamics towards the maximum power limit with a fast, positive and a slow,
negative feedback that compensate each other at the maximum power state. We
close with a discussion of the importance of a planetary, thermodynamic view of
the whole Earth system, in which thermodynamics limits the intensity of the
dynamics, interactions strongly shape these limits, and the spatial organization of
flow represents the means to reach these limits.
