That’s not what I meant, I meant if all organic life that produces oxygen disappeared.

Photosynthesis is generally so slow at it’s job that the current oxygen levels were only built up over hundreds of millions of years. Furthermore, Rubisco, a key enzyme in photosynthesis, surprisingly, is slow and not very good at distinguishing oxygen from carbon dioxide, because it evolved before there was much oxygen on Earth. Therefore a lot of oxygen was produced at the beginning, most of the oxygen we have today in fact, and then not very much thereafter.

Additionally, the Earth’s oxygen levels stay stable due to the release of oxygen trapped in minerals. Over those hundreds of millions of years, they absorbed it. This absorption and release has kept levels stable for well beyond our existence.

At least that’s what I got from the PBS video. If you don’t agree, go argue with them, I’m no expert. I’m just forwarding what I learned.

I just thought it was an interesting video that challenges what I previously understood about one specific thing 😅 I’m not advocating against the environment, neither is the video, that’d be terrible for many reasons. It’s just that the video is from PBS and seems pretty evidence based in why photosynthesis is quite terrible at converting CO2 to oxygen due to the shortcomings of the enzyme Rubisco and how we could improve that. Nothing more than that. Give it a watch, it’s not some anti-environment conspiracy video

I love nature, but interestingly apparently photosynthesis doesn’t actually contribute all that much oxygen and Earth’s levels would stay stable for millions of years if all organic matter disappeared. We’d have many, many other problems, but not that one specifically:

https://youtu.be/DZ_T4zMBx6E