2+ billion years ago when anaerobic blue-green algae in our planet’s warm hospital oceans were munching away on H2O and CO2 and emitting oxgen as a waste product to make complex organic compounds, I wonder if some heretical fringe element of algae were like “Oh my God. We’re all emitting oxygen. And there are so many of us. We’re ANAEROBIC, guys. Don’t you see? Our livelihoods in excess will be the very cause of our demise.”

Probably not.

Neways. Thanks for the ozone layer, guys.