---
slug: school-maximum-entropy-production-principle-mepp-ozawa-paltridge
title: Maximum Entropy Production Principle (MEPP, Ozawa/Paltridge)
canonical: https://miscsubjects.com/a/school-maximum-entropy-production-principle-mepp-ozawa-paltridge
---

## What the subject saw and its core results

Hisashi Ozawa and Garth Paltridge examined far-from-equilibrium flow systems. They observed that such systems reach steady states that maximize the rate of entropy production under given constraints. Ozawa reviewed applications across climate and fluid systems. Paltridge applied the principle to global atmospheric circulation and cloud feedbacks.

Core result one: the climate system settles into a configuration where meridional heat transport produces entropy at the highest rate consistent with energy balance. Core result two: this selection rule reproduces observed temperature and cloud distributions without detailed microphysical tuning. Core result three: the same rule applies to laboratory convection and shear turbulence.

## Exact primary works and passages

Ozawa, H., Ohmura, A., Lorenz, R. D., & Pujol, T. (2003). The second law of thermodynamics and the global climate system: A review of the maximum entropy production principle. Reviews of Geophysics, 41(4). The paper states: “the long-term mean states of the climate system of the Earth... correspond... to a state in which the rate of entropy production due to thermal and viscous dissipation is at a maximum.”

Paltridge, G. W. (1975). Global dynamics and climate — a system of minimum entropy exchange. Quarterly Journal of the Royal Meteorological Society, 101, 475–484. Paltridge modeled the atmosphere as a system whose steady state maximizes entropy production.

Paltridge, G. W. (2007). Maximum entropy production, cloud feedback, and climate change. Geophysical Research Letters, 34, L14708. The model uses the MEP constraint to predict cloud response to doubled CO2.

Martyushev, L. M., & Seleznev, V. D. (2006). Maximum entropy production principle in physics, chemistry and biology. Physics Reports, 426(1), 1–45. This review compiles independent derivations and applications.

## Convergence patterns touched

MEPP independently derives flow networks. Heat transport organizes into meridional cells that maximize dissipation. It derives bounded chaos. Turbulent eddies increase entropy production until the steady state is reached. It derives scale invariance. The same extremum condition appears from laboratory convection cells to planetary atmospheres. It touches memory. The selected steady state persists as long as boundary conditions remain fixed.

## Distance from the full synthesis

MEPP reaches the step from flow to structure. It supplies a selection rule for pattern formation in dissipative systems. It stops short of memory to life. No mechanism links maximized entropy production to self-replicating chemistry or genetic storage. It stops short of life to mind. No account addresses how maximized dissipation produces internal models or the Mirror Layer in which the observer sits inside the system.

## Honest limits and disconfirming edges

The principle requires external constraints on fluxes or forces. Under constant force the system maximizes production; under constant flux it may minimize it. This dependence supplies the main internal objection. Reductionist critics note that MEPP remains a conditional extremum principle rather than an unconditional law. Applications to biology remain speculative because no clear time-scale separation exists between abiotic and biotic entropy production. No derivation yet shows why maximum production must hold across all far-from-equilibrium regimes without additional assumptions.

## Claims

The body above contains the following atomic claims, each graded by tier.

- Nonlinear flow systems reach steady states that maximize entropy production rate under fixed constraints. Tier: mechanistic. Source: Ozawa et al. 2003.
- Paltridge’s 1975 model reproduces observed meridional temperature gradients by imposing the MEP condition. Tier: anecdotal (historical attribution of model performance). Source: Paltridge 1975.
- The 2003 Ozawa review states that Earth climate, Mars atmosphere, and mantle convection correspond to states of maximum entropy production. Tier: anecdotal. Source: Ozawa et al. 2003.
- MEPP reproduces cloud feedback behavior in a steady-state energy-balance model. Tier: mechanistic. Source: Paltridge 2007.
- The principle applies to laboratory thermal convection and shear turbulence. Tier: mechanistic. Source: Ozawa et al. 2003.
- Selection of maximum production requires specification of whether forces or fluxes are held constant. Tier: mechanistic. Source: Martyushev & Seleznev 2006.
- MEPP supplies no pathway from maximized dissipation to self-replicating chemical systems. Tier: speculative. Source: none (explicit limit statement).
- No derivation within MEPP literature addresses internal models or observer-system identity. Tier: speculative. Source: none (explicit limit statement).
