liveforphysics said:
However, I would not choose to do this same behavior in our singular atmospheric life support system today after thinking for myself about the reality of living in an effectively closed loop system. Earth is pretty impressively isolated by ~93million miles of vacuum. Last month alone I traveled through UK, Germany, Croatia, Hong Kong, and Japan (Tokyo police have my Phantom 4 for ~$2400 ransom now

...I bought another used one in much better shape on Craigslist for $940

). It's only a relatively brief flight away to acces anywhere on the earth, the currently practiced model of treating it like an infinite dumping ground for billions to pollute at whatever rate they can afford is soon going to find the reality of how finite and closed loop this beautiful isolated tiny blue marble happens to be.
All the carbon in hydrocarbons is coming from CO2 that has effectively been sequestered away by trees/plant-life/dinosaurs/mammals/carbon-lifeforms/etc. turning into oil. So, all that's really happening with fossil fuel combustion is returning the carbon back to the atmosphere from where it came millions of years ago. However, the relatively high level of NOX emissions is certainly novel to the atmosphere, especially when concentrated as it is in populated areas (Especially in areas where the average driving distance is absurd... i.e.... Houston.). I'm guessing it's negligible outside the populated areas.
What's intersting to me... however... is oxygen since it's being depleted to create CO2. But, if carbon dioxide emissions results in a warmer planet with a greater rate of evaporation/precipitation globally, then I guess that'd probably be offset in the longterm by increased plant life, as plants love the warmth, water (via global warming) and CO2 that fossil fuel emissions provide. So it's probably a wash in the end. I still don't know where new oxygen enters the system... however... recycling CO2 for O2 just gets the oxygen back... so it wouldn't increase oxygen levels over the longterm unless there were other oxygen sources.
It obviously comes from somewhere, to have arisen from nothing.
Well... maybe all the oxygen came from CO2 originally (When the bluegreen algae started converting CO2 into O2, thus oxygenating the atmosphere)... so O2 has been really just riding off of CO2 all along. And, the C was just getting absorbed to form the cells in the carbon-based blue-green algae lifeform.
I wonder what happens to O2 levels if we burned off all the fossil fuel, initially. I know eventually, it'll get turned back into O2 by plant life... as it always has...
I wonder if places like those 2-mile-high cities (Like Bogota, Columbia) would become inhospitable to human life.
It would seem unlikely we'll burn off 'all the fossil fuels' anytime soon since society is rapidly approaching the point where fossil fuels are not cost competitive with solar, as fossil fuel prices increase and solar decreases. The vast majority of fossil fuels, globally, is likely too expensive to ever extract and refine. And, if it ever gets extracted/refined, it's likely because the ridiculously cheap and abundant solar will be creating/running the machines that do so, as it'd be unproductive to use fossil fuels from those sources to extract/refine fossil fuels from those sources. I guess the question is if we'll ever get to that point... niche applications for fossil fuels and all that...