It's all oxygen..
It's just a difference in the number of atoms...
Right, but it is too different molecules with two different characteristics, produced by different processes.
- Oxygen in the atmosphere in the early earth - 0%
- Oxygen in the atmosphere 200 million years ago - 10%
- Oxygen today 20%
- CO2 in the atmosphere in the early earth - 80.0%
- C02 in the atmosphere 200 million years ago - 15.0%
- CO2 today 0.038%
Take any time period and you will see something similar. Why the changes? Plants of course.
I don't know why this information is not taken into account by Climate researchers.