<p>Not directly.  What possibly could happen is that rising temperatures turn the parts of the ocean anoxic, which leads to large releases of hydrogen sulfide, which is toxic: <a href="https://www.chemistryworld.com/news/ocean-chemistry-changes-triggered-earths-greatest-extinction-event/2500368.article" rel="nofollow noreferrer">https://www.chemistryworld.com/news/ocean-chemistry-changes-triggered-earths-greatest-extinction-event/2500368.article</a></p>

CC BY-SA 4.0
2019-10-19T02:38:05.297Z
2019-10-19T02:38:05.297Z
jamesqf
<blockquote>
  <p>Although conventional oil, gas and
  coal reserves total between 829 and 1,501 GtC, estimates of the global recoverable fossil fuel resource including oil shales range upwards from about 4,000
  GtC. If exotic resources, especially methane hydrates, are included the total
  may be 15,000-25,000.<br>
  <a href="https://www.researchgate.net/publication/225712889_Millenial_timescale_carbon_cycle_and_climate_change_in_an_efficient_Earth_system_model" rel="nofollow noreferrer">Millenial timescale carbon cycle and climate change in an efficient Earth system model</a></p>
</blockquote>

<p><a href="http://ccdatacenter.org/documents/RFandCS.pdf" rel="nofollow noreferrer">There are 2.12 GTC for 1 PPM of atmospheric CO2</a> so the high estimate would be ~10,000 ppm, or 1% of the atmosphere, consuming 5% the O2. If the FF are mostly CH4, the hydrogen would consume another 5% of the O2.</p>

<p>Also <a href="https://thinkprogress.org/exclusive-elevated-co2-levels-directly-affect-human-cognition-new-harvard-study-shows-2748e7378941/" rel="nofollow noreferrer">Elevated CO2 Levels Directly Affect Human Cognition</a> (1400 ppm).</p>

CC BY-SA 4.0
2020-01-05T22:56:10.133Z
@ebv Thanks. Not nearly as doomy, then.
Keith McClary
CC BY-SA 4.0
2020-01-06T01:44:02.217Z
@ebv All the fossil fuels came from periods where complex life existed. I really, really doubt that it’d kill everything, even in the worst case.
nick012000
CC BY-SA 4.0
2020-01-05T21:43:59.240Z
2020-01-09T23:51:07.957Z
2020-01-09T23:51:07.957Z
Keith McClary
<p>No. For a start, humanity will not burn all the fossil fuels it can find. But let's suppose for the sake of argument that humanity recognises no restrictions and fulfils all its energy needs by burning fossil fuels. Only a limited amount of fossil fuels are recoverable; the vast majority will have to stay in the ground.</p>

<p>Oil, for example, won't suddenly run out. What would happen is that it would gradually become scarcer, and increasingly expensive to recover. Eventually it would become too expensive to burn, so humans would have to turn to other fossil fuels, coal being the obvious one. Some would be used to make synthetic oil, and some burned in its natural state. The world has very large recoverable reserves of coal There could be enough to last humanity for a thousand years, but eventually recoverable reserves would become so scarce that it too would become too expensive to burn and, like oil, would be used as a source of chemicals and plastics.</p>

<p>All these fuels together, oil, gas and coal, might conceivably be burned for 2,000 years before becoming too scarce and expensive to be used as fuels. During that time,plants,especially in the oceans, would not be idle. Much of the CO2 generated would be sequestered by natural means, and although there would be a big rise in atmospheric CO2 with consequent climate warming, it wouldn't be nearly enough to make the atmosphere unbreathable.</p>

CC BY-SA 4.0
2019-10-19T07:50:26.397Z
Once again, Michael, citation needed. The scientific literature oftentimes runs contrary to your claims.
David Hammen
CC BY-SA 4.0
2019-10-19T09:17:38.353Z
I have explained that it is impossible to extract all fossil fuels from the ground, and even if mankind said to hell with chemicals and plastics, lets burn it all,it wouldn't make very much difference. CO2 is not very toxic,your longs always contain plenty, and air would still be breathable with1 percent CO2 as opposed to the tiny fraction of one percent we now have. If my tweets were often contradictory to scientific thinking, people would soon let me know about it, but they don't.
Michael Walsby
CC BY-SA 4.0
2019-10-19T18:36:17.913Z
@Michael Walsby: CO2 is not very toxic?  The people around Lake Nyos might disagree with you, if you had a good medium: https://en.wikipedia.org/wiki/Lake_Nyos_disaster  Also the approximately 90 people killed (in the US) by CO2 intoxication: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5380556/
jamesqf
CC BY-SA 4.0
2019-10-19T18:49:59.590Z
Anything is toxic if you take too much of it. Dozens of culinary substances can be fatal if you take too much:  water, salt, sugar, vinegar etc. Arsenic can be fatal if you take either too much or too little. In some circumstances oxygen and nitrogen can be toxic, Your lungs have a lot of CO2 in them at this very moment.
Michael Walsby
CC BY-SA 4.0
2020-01-15T01:18:10.957Z
@jamesqf there is nowhere near enough CO2 in the air to form any direct toxic danger to humans. There has to be multiple orders of magnitude more CO2 in the air we breathe to worry. We’re at 400ppm. We’re nowhere near 100,000ppm, and I can’t imagine we will ever get there.
Tim
CC BY-SA 4.0
2019-10-18T21:01:30.720Z
2019-10-18T21:01:30.720Z
Michael Walsby
<p>What if humanity burns all fossil fuels it can find? Putting the negative effects of climate change aside, would the enormous amount of <span class="math-container">$\small\mathsf{CO_2}$</span> in the atmosphere eventually make it unbreathable?  </p>

CC BY-SA 4.0
2019-10-20T00:54:10.487Z
in what time span, if they burned it all in a day it would have a strong immediate impact.
John
<atmosphere><climate-change><fossil-fuel>
Could burning all fossil fuels (available on earth) render the atmosphere unbreathable?
Westin Ritter
# Could burning all fossil fuels (available on earth) render the atmosphere unbreathable?

(Asked by: username_0 on 2019-10-18)

What if humanity burns all fossil fuels it can find? Putting the negative effects of climate change aside, would the enormous amount of $\small\mathsf{CO\_2}$ in the atmosphere eventually make it unbreathable?

**Tags:** atmosphere, climate-change, fossil-fuel

> **Comments:**
> **username_1**: in what time span, if they burned it all in a day it would have a strong immediate impact.  

---

## 3 answers

### Answer by username_2 on 2019-10-19. Score: 1

Not directly. What possibly could happen is that rising temperatures turn the parts of the ocean anoxic, which leads to large releases of hydrogen sulfide, which is toxic: <https://www.chemistryworld.com/news/ocean-chemistry-changes-triggered-earths-greatest-extinction-event/2500368.article>


---

### Answer by username_3 on 2020-01-05. Score: 0

> Although conventional oil, gas and
> coal reserves total between 829 and 1,501 GtC, estimates of the global recoverable fossil fuel resource including oil shales range upwards from about 4,000
> GtC. If exotic resources, especially methane hydrates, are included the total
> may be 15,000-25,000.  
> [Millenial timescale carbon cycle and climate change in an efficient Earth system model](https://www.researchgate.net/publication/225712889_Millenial_timescale_carbon_cycle_and_climate_change_in_an_efficient_Earth_system_model)

[There are 2.12 GTC for 1 PPM of atmospheric CO2](http://ccdatacenter.org/documents/RFandCS.pdf) so the high estimate would be ~10,000 ppm, or 1% of the atmosphere, consuming 5% the O2. If the FF are mostly CH4, the hydrogen would consume another 5% of the O2.

Also [Elevated CO2 Levels Directly Affect Human Cognition](https://thinkprogress.org/exclusive-elevated-co2-levels-directly-affect-human-cognition-new-harvard-study-shows-2748e7378941/) (1400 ppm).

> **Comments:**
> **username_3**: @ebv Thanks. Not nearly as doomy, then.  
> **username_4**: @ebv All the fossil fuels came from periods where complex life existed. I really, really doubt that it’d kill everything, even in the worst case.  

---

### Answer by username_5 on 2019-10-18. Score: -2

No. For a start, humanity will not burn all the fossil fuels it can find. But let's suppose for the sake of argument that humanity recognises no restrictions and fulfils all its energy needs by burning fossil fuels. Only a limited amount of fossil fuels are recoverable; the vast majority will have to stay in the ground.

Oil, for example, won't suddenly run out. What would happen is that it would gradually become scarcer, and increasingly expensive to recover. Eventually it would become too expensive to burn, so humans would have to turn to other fossil fuels, coal being the obvious one. Some would be used to make synthetic oil, and some burned in its natural state. The world has very large recoverable reserves of coal There could be enough to last humanity for a thousand years, but eventually recoverable reserves would become so scarce that it too would become too expensive to burn and, like oil, would be used as a source of chemicals and plastics.

All these fuels together, oil, gas and coal, might conceivably be burned for 2,000 years before becoming too scarce and expensive to be used as fuels. During that time,plants,especially in the oceans, would not be idle. Much of the CO2 generated would be sequestered by natural means, and although there would be a big rise in atmospheric CO2 with consequent climate warming, it wouldn't be nearly enough to make the atmosphere unbreathable.

> **Comments:**
> **username_6**: Once again, username_5, citation needed. The scientific literature oftentimes runs contrary to your claims.  
> **username_5**: I have explained that it is impossible to extract all fossil fuels from the ground, and even if mankind said to hell with chemicals and plastics, lets burn it all,it wouldn't make very much difference. CO2 is not very toxic,your longs always contain plenty, and air would still be breathable with1 percent CO2 as opposed to the tiny fraction of one percent we now have. If my tweets were often contradictory to scientific thinking, people would soon let me know about it, but they don't.  
> **username_2**: @username_5: CO2 is not very toxic?  The people around Lake Nyos might disagree with you, if you had a good medium: https://en.wikipedia.org/wiki/Lake_Nyos_disaster  Also the approximately 90 people killed (in the US) by CO2 intoxication: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5380556/  
> **username_5**: Anything is toxic if you take too much of it. Dozens of culinary substances can be fatal if you take too much:  water, salt, sugar, vinegar etc. Arsenic can be fatal if you take either too much or too little. In some circumstances oxygen and nitrogen can be toxic, Your lungs have a lot of CO2 in them at this very moment.  
> **username_7**: @username_2 there is nowhere near enough CO2 in the air to form any direct toxic danger to humans. There has to be multiple orders of magnitude more CO2 in the air we breathe to worry. We’re at 400ppm. We’re nowhere near 100,000ppm, and I can’t imagine we will ever get there.  

---

