<p>I am in <strong>no way</strong> a climate-change skeptic, nor a denier. Motivated by <a href="https://earthscience.stackexchange.com/questions/23144/how-to-explain-the-remarkable-regularity-of-the-increased-concentration-of-atmos?newreg=f650c03c5b034a238aed9a2797b036b5">this</a> question and some articles I read online:</p>
<p>Are there any known natural processes beside human activities that are able to explain the (geologically recent) rise in atmospheric CO<span class="math-container">$_2$</span> concentration?</p>
<p>I'm also curious about this because I often hear climate change skeptics bring this up and I'm not sure how to respond.</p>

CC BY-SA 4.0
2021-11-16T18:56:20.407Z
This question is pretty much a duplicate, so I've flagged it as such. The answer is in the isotopic signature of the CO2 -- CO2 from fossil sources is isotopically distinct from other sources, so we can measure the makeup of CO2 in the atmosphere and identify that the increased volume above the 280ppm baseline is from burning coal and oil.
jeffronicus
CC BY-SA 4.0
2021-11-16T18:59:58.393Z
(2) is a duplicate of the question jeffronicus linked. You should edit to only ask (1).
LShaver
CC BY-SA 4.0
2021-11-16T23:19:47.923Z
Is there an aspect that isn't answered on the other question? The additional CO2 is clearly from fossil fuels, so there's not really any wiggle room.
jeffronicus
CC BY-SA 4.0
2021-11-16T23:24:50.803Z
I guess it's tough to argue that a different mechanism is responsible, when one can simply go to wikipedia and add up the emission numbers for the biggest countries per year, and compare that to the measured rise in $CO_2$-levels in the atmosphere. One will then find that the increase in carbon is in fact overexplained by the emissions (half of all emissions get currently buried in the Ocean, i.e. the missing carbon problem).
AtmosphericPrisonEscape
CC BY-SA 4.0
2021-11-17T15:33:08.997Z
There is a deep carbon cycle, where carbon goes into the mantle through subduction, and back into the atmosphere as CO$_2$ through volcanism. This is normally at equilibrium, but I can imagine that enhanced volcanic activity (such as large igneous province emplacement) could temporarily enhance atmospheric release of CO$_2$ by volcanism. However, such thing did not happened in geologically recent times. So I just mention it as a natural process that *could* trigger a rise in CO$_2$ concentration, but *did not* triggered the recent one.
Jean-Marie Prival
CC BY-SA 4.0
2021-11-17T16:40:14.467Z
@Jean-MariePrival Thank you. That's precisely the kind of answer I'm curious about: possible natural mechanisms/processes that could, in principle, explain the CO2 concentration
Daddy Kropotkin
CC BY-SA 4.0
2021-11-17T16:42:04.213Z
@AtmosphericPrisonEscape Of course.... As I said I'm not denying that nor am I skeptical of that. I am literally asking about whether there are known processes/mechanisms that could, in principle, explain such CO2 concentration rise. I don't think it's so hard to understand why I would ask this, when in science it is common to have many possible explanations for some phenomenon, even if it is obvious that one is better than the others. I'm asking about the other possibilities.
Daddy Kropotkin
<climate-change><co2><carbon-cycle><human-influence>
Alternative natural explanations for rise in atmospheric CO2?
Daddy Kropotkin
# Alternative natural explanations for rise in atmospheric CO2?

(Asked by: username_0 on 2021-11-16)

I am in **no way** a climate-change skeptic, nor a denier. Motivated by [this](https://earthscience.stackexchange.com/questions/23144/how-to-explain-the-remarkable-regularity-of-the-increased-concentration-of-atmos?newreg=f650c03c5b034a238aed9a2797b036b5) question and some articles I read online:

Are there any known natural processes beside human activities that are able to explain the (geologically recent) rise in atmospheric CO$\_2$ concentration?

I'm also curious about this because I often hear climate change skeptics bring this up and I'm not sure how to respond.

**Tags:** climate-change, co2, carbon-cycle, human-influence

> **Comments:**
> **username_1**: This question is pretty much a duplicate, so I've flagged it as such. The answer is in the isotopic signature of the CO2 -- CO2 from fossil sources is isotopically distinct from other sources, so we can measure the makeup of CO2 in the atmosphere and identify that the increased volume above the 280ppm baseline is from burning coal and oil.  
> **username_2**: (2) is a duplicate of the question username_1 linked. You should edit to only ask (1).  
> **username_1**: Is there an aspect that isn't answered on the other question? The additional CO2 is clearly from fossil fuels, so there's not really any wiggle room.  
> **username_3**: I guess it's tough to argue that a different mechanism is responsible, when one can simply go to wikipedia and add up the emission numbers for the biggest countries per year, and compare that to the measured rise in $CO_2$-levels in the atmosphere. One will then find that the increase in carbon is in fact overexplained by the emissions (half of all emissions get currently buried in the Ocean, i.e. the missing carbon problem).  
> **username_4**: There is a deep carbon cycle, where carbon goes into the mantle through subduction, and back into the atmosphere as CO$_2$ through volcanism. This is normally at equilibrium, but I can imagine that enhanced volcanic activity (such as large igneous province emplacement) could temporarily enhance atmospheric release of CO$_2$ by volcanism. However, such thing did not happened in geologically recent times. So I just mention it as a natural process that *could* trigger a rise in CO$_2$ concentration, but *did not* triggered the recent one.  
> **username_0**: @username_4 Thank you. That's precisely the kind of answer I'm curious about: possible natural mechanisms/processes that could, in principle, explain the CO2 concentration  
> **username_0**: @username_3 Of course.... As I said I'm not denying that nor am I skeptical of that. I am literally asking about whether there are known processes/mechanisms that could, in principle, explain such CO2 concentration rise. I don't think it's so hard to understand why I would ask this, when in science it is common to have many possible explanations for some phenomenon, even if it is obvious that one is better than the others. I'm asking about the other possibilities.  

---

## 0 answers

