This was a pretty cool read, I hadn’t thought much about the entropy of a non-isolated system. I’m still not sure it has much physical meaning - the idea that entropy always increases only applies to isolated systems, but it made me think more about where the entropy gain would have to be to achieve a lower entropy mineral/energy world.
You need an entropy gradient to reverse entropy in the open system. For us this is sunlight vs cosmic microwave background. And decay of radioactive elements, plus gravitational energy, chemical energy etc., vs above sink. Exergy https://en.wikipedia.org/wiki/Exergy is potentially a useful concept here, too.
Obviously how well you can use an entropy gradient depends on the level of technology. In theory molecular nanotechnology can do everything biology can, and considerably more. But we need to get there, and that path must go through a high-technology regime. Which we are about to lose, unless I am mistaken.
Like you said, there’s plenty of external forces affecting the entropy of a closed “earth” system, and so the notion of a closed system seems a bit meaningless to me. I probably have some more reading to do on this tbh. I tend to take the view that everything is a single closed system (i.e. universal wavefunction) and so talking about smaller subsystems is helpful but never exact.
I think i might be a bit more optimistic on how well we can use these “entropy gradients” to our advantage. I study computational nanotechnology for a living, so ofc i’m a lil bullish on it, but generally i think that our current high technology regime can get us far enough past scarcity, it’s mainly the sociopolitical implications of doing so that i worry would stop us first.
