# Too much oxygen and not enough carbon

## If a planet has a lot of oxygen to support mega flora and fauna, how much would be too much?

My planet has the oxygen content about that of the carboniferous(as a starter example), which had a about 35 percent oxygen atmosphere.

During that period, giant bugs, massive plants, etc. all existed. My planet's atmosphere is at least 40 and/or 45 percent oxygen. Can all of that oxygen kill life and, if it could, how can I combat it?

One of my solutions was super volcanoes, or geysers, that spew carbon into the atmosphere.

I can't, however, have volcanoes erupting every day, so how can I fix this problem? I eventually want the oxygen to start killing all life, so how can I have that, too?

edit - What would happen to a human living on the planet? Would the oxygen kill them,or something else entirerly

• Can you please clarify your question? Try also using formatting to remove the wall of text.
– L.Dutch
Oct 20, 2021 at 2:45
• can a lot or to much oxygen kill life on a planet and how can you counter it with carbon or other methods Oct 20, 2021 at 2:48
• What is the problem? Do you want to understand the limits of the Oxygen levels that life can tolerate - or do you want to know by what processes Oxygen levels can be reduced? Can you narrow it to one clear question for us. Could you also tell us what the atmospheric pressure is on your world? Oct 20, 2021 at 2:50
• the limits of the oxygen levels and the atmosphere is like the cabonifeoius on earth its oxygen was up to 20 percent more or 35 i wanted to double it so lets say 40 or 35 Oct 20, 2021 at 2:54
• it atmosphere is similar to that of earth but just more oxygen Oct 20, 2021 at 2:55

my planet has the oxygen content to that of the carboniferous, when giant bugs existed and so on, but maybe twice as much. Can all of that oxygen kill life

Since you state yourself that with that oxygen level there were giant bugs, the answer is no, that much oxygen won't kill life. It will only kill life not adapted to it.

Oxygen, being an highly reactive gas, is self limiting in its atmospheric concentration, because it will tend to react with whatever is available for oxidation: it can be minerals, it can be life (faster decomposition or more frequent fires).

Mind that putting carbon to regulate oxygen will likely shift you into the greenhouse problem, because of the produced CO2.

• so increased global warming then Oct 20, 2021 at 10:40
• Not just increased global warming. Earth's atmosphere is 0.04% CO2. If your volcanos are adding enough carbon to consume a significant fraction of the atmospheric O2 (which would itself be odd, since it'd normally combine with oxygen from the molten rock and be released as CO2), then you are building a largely CO2 atmosphere. And if that CO2's not being photosynthesized back into O2 as fast as the volcanos release the carbon to produce it, it raises the question of how you got that oxygenated atmosphere in the first place. Nov 15, 2021 at 15:02

This has already happened on Earth, the Great Oxygenation Event caused a mass extinction of most life on Earth. At that time most organisms were anaerobic, they metabolised their food without oxygen. Oxygen was basically poisonous to them.

Oxygen is reactive and bonds with iron and other things, but eventually the Earth was oversaturated with oxygen and it caused havoc.

The remedy was for organisms to evolve that used oxygen as fuel.

Your intermittent volcanoes would work to keep from entering an ice age perhaps. In the above mentioned event oxygen is thought to have bonded with methane which is a better greenhouse gas than CO2 and this caused the Earth to enter an Ice age.

Do not fight with it, use it.

Oxygen react with everything. But most important thing is self-regulation. If have carbon related life and plants then remember: plants are inflammable at 30% oxygen and 1 atm most Earth trees can be set in fire even if wet. When dry - look at California or Australia firestorms. Fires can reduce plant life and that can reduce oxygen generation. On second side have $$CO_{2}$$ and temperature rise, drying land and more fires. Can balance it with lots of rains. $$CO_{2}$$ can dissolve in droplets and then erode rocks. Seas can be hardly habitable for any animal life because of $$CO_{2}$$ level and $$H_{2}O_{2}$$ level. Good if have something generating oxygen in seas and dropping carbon into seabed. That reduce available carbon on lands and in air.

Imagine some kind of seaweed which make big mat on surface and then grow up into air long thin flower. Lots of them make inflammable oils and when is enough of them there they spontaneously get in fire. Half of sea in fire, lots of smoke, lots of water boiling, seaweed dropping to sea floor, all animals die. But seaweed seeds go up with ascending air and smoke and reach other side of planet. And then when all that steam cool down enormous, 100 days rains starts. You can even evolve some bugs which advantage on it; some use air to drift long distances, some attach eggs to seeds and when dropped down they hatch and start to eat new seaweed to be ready for next egg laying...

*TWICE the oxygen content of the Carboniferious period?

SO your atmosphere is a bit more than 1 bar pressure, and 70% Oxygen by composition.

Fire,
Fire,
Fire,
Fire,
Fire,
Fire,
Fire,
Fire,
Fire,
Fire,
Fire,
Fire,
Fire,
Fire,
and fire.

At THAT oxygen concentration, even human fat is flammable, if you get it started. Read up about fire in oxygen tents, Apollo-1 disaster, etc.

• yeah sorry i forgot to edit that out.the carboniferous oxygen was about 35 percent so id say my planet is maybey about 40 or 45 percent or or just 30 at the lowest. Nov 15, 2021 at 12:00