^ One good thing is that science does not care about politicians or opinions
Marc: The amount of oxygen we have in the atmosphere depends on plants producing O2, which usually is being bound in CO2 again when the plant dies. This is a zero number game.
What gives us an O2 surplus is when plants (marine (plankton) or terrestrial) die
without being oxidized (=binding O2 again taking it out of the atmosphere).
This means they do not rot, but are being taken out of the cycle by being buried under sediments or whatever, essentially kept off the free O2 in the atmosphere.
The amount of oxygen being spared from oxidizing this dead stuff is what gives us surplus oxygen.
The existing plants hold us on a given level based on millions of years.
(B.t.w. the amount of oxygen/O2 in the earth's atmosphere has already been higher e.g. during jurassic times some million years ago)
Now you tell me what happens if you burn fossil fuels thus oxidizing the stuff.
Rising CO2 levels fuelling the glasshouse effect is a side show adding to the rest.
But add deforesting large areas for whatever reason to all that and you probably get what it all is about.