The Entropy Barrier: Why Sustainability Demands Space

We present a thermodynamic framework for quantifying environmental damage based on the entropy production of open systems. Extending the approach of Golovinski et al. (2023), we derive a universal environmental efficiency coefficient $\eta = C_{\text{market}}/(C_{\text{market}} + C_{\text{entropy}})$, where $C_{\text{entropy}}$ is the cost of compensating the entropy generated throughout the full life cycle of a project. The inequality $\eta < 1$ is shown to be a direct consequence of the second law, analogous to the Carnot limit for heat engines. The methodology is applied to compare solar PV and gas turbine equipment production, revealing that at the manufacturing stage gas turbines appear cleaner ($\eta \approx 0.95$ vs. $0.89$), but full life cycle analysis reverses the advantage in favour of solar, especially under IEA decarbonisation scenarios. We also examine data centre siting: mid‑latitudes ($\eta=0.79$), polar regions ($\eta=0.88$) and the Moon ($\eta=0.83$); while polar sites are optimal on Earth, only space‑based centres avoid adding heat to the biosphere, making them globally entropy‑neutral. Protein production efficiency is compared: beef $\eta \approx 0.10$–$0.15$, poultry $0.35$–$0.45$, plant proteins $0.85$–$0.95$, highlighting the thermodynamic advantage of short trophic chains. Nuclear energy analysis shows that traditional open‑fuel‑cycle reactors achieve $\eta \approx 0.68$, whereas the Russian closed‑cycle “Proryv” (BREST‑OD‑300) reaches $\eta \approx 0.93$ – the highest among all considered technologies. Anthropogenic CO$_2$ emissions are placed in context: they are 140–250 times larger than all volcanic emissions combined, and their continuous growth disrupts Earth’s entropy balance. Two fundamental strategies for dealing with entropic pollution are compared – terrestrial isolation versus active dumping into space. We argue that because Earth’s capacity to absorb entropy is finite, expanding the disposal reservoir into space is not a futuristic speculation but a thermodynamic necessity for sustainable civilisation.