<p>As well as the atmosphere having a lot of mass, there are many processes which remove CO<sub>2</sub> from the atmosphere, see the wikipedia article for <a href="https://en.wikipedia.org/wiki/Carbon_cycle" rel="noreferrer">the carbon cycle</a>. Plants sequester it as biomass, some of which ultimately ends up in the soil long-term (the rest is either released again by organic decay or fires). The ocean also absorbs a lot, which is related to the problem of ocean acidification you may have heard of.</p>
<p>It's a delicately balanced dynamic equilibrium that we are disrupting, not a static situation. Think of it like a sink with a half blocked drain that's slowly filling up as you run the water, rather than an empty bowl you're filling up.</p>

CC BY-SA 4.0
2023-11-20T15:37:03.043Z
2023-11-21T19:02:17.917Z
2023-11-21T19:02:17.917Z
llama
<p>&quot;Small&quot; is a vague and slippery term. There is now a lot <em>more</em> CO2 in the atmosphere than there was a century ago and that change has consequences, especially to climate stability. There is a lot more human emissions - around 40 billion metric tons per year globally now - and that is causing atmospheric concentrations to rise. Those emissions are in addition to natural sources and are moderated by natural processes that absorb and recycle Carbon and overall, so far, natural processes have been taking CO2 back out of the atmosphere at rates greater all the natural CO2 flow into the atmosphere, or the human addition would be making concentrations rise faster than they are.</p>
<p>This diagram shows The Carbon Cycle. It is a few years out of date - the amounts of fossil fuel burning and other numbers will have changed a bit but it gives a good overview of where the carbon is coming from and going to.</p>
<p><a href="https://i.sstatic.net/st9sM.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/st9sM.jpg" alt="Global Carbon Cycle" /></a></p>

CC BY-SA 4.0
2023-11-22T21:31:21.763Z
2023-11-22T21:31:21.763Z
Ken Fabian
<p>The <a href="https://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html" rel="nofollow noreferrer">mass of the atmosphere</a> is 5.1 × 10<sup>18</sup> kg, which is 5.1 × 10<sup>15</sup> t.</p>
<p>As stated in the edited question,</p>
<blockquote>
<p>industries emits 1.5 billion metric tons of carbon dioxide each year,</p>
</blockquote>
<p>That's 1.5 × 10<sup>9</sup> t.</p>
<p>The mass of Earth's atmosphere is 3,400,000 times the mass of CO<sub>2</sub> that industries produces each year in the US.</p>

CC BY-SA 4.0
2023-11-19T14:01:30.787Z
Is that a US ton that you're using for units?  Google suggests the proper conversion from 1000kg to t would yield 5.6.
Mark Ransom
CC BY-SA 4.0
2023-11-19T14:39:28.360Z
@MarkRansom the original article is in metric tons
Alan Birtles
CC BY-SA 4.0
2023-11-19T14:56:05.367Z
@AlanBirtles I was unaware that the abbreviation of metric ton was also `t`.  Thanks for straightening me out.
Mark Ransom
CC BY-SA 4.0
2023-11-19T15:25:37.393Z
Hmmm using worldwide CO2 concentration and US CO2 emissions. That's weird.
Joshua
CC BY-SA 4.0
2023-11-19T19:09:09.693Z
@Joshua, I don't think atmospheric CO2 respects our border wall.
Solomon Slow
CC BY-SA 4.0
2023-11-19T19:33:39.970Z
@SolomonSlow: Neither do I. I think it should be worldwide CO2 concentration and worldwide CO2 emissions.
Joshua
CC BY-SA 4.0
2023-11-20T09:10:08.467Z
@Joshua : the question specifically asked why it is low despite those 1.5 billion tons. This answer shows exactly those 1.5 billion tons in perspective, therefore it answers the question better than if it used global emissions. Even if the answer was expanded to include global emissions, it needs those 1.5 billion tons, so that the OP can see how it relates.
vsz
CC BY-SA 4.0
2023-11-20T21:09:28.360Z
An [imperial ton](https://en.wikipedia.org/wiki/Long_ton) is practically the same (at least in this context) as a metric ton (about 2% difference. 1,016 kg). The [short ton](https://en.wikipedia.org/wiki/Short_ton) is further from, but still close (10% lower. 907 kg).
Peter Mortensen
CC BY-SA 4.0
2023-11-19T00:12:35.330Z
2023-11-22T17:50:05.707Z
2023-11-22T17:50:05.707Z
Fred
<p>Given the fact that <a href="https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions" rel="nofollow noreferrer">industries emit about 1.5 billion metric tons of carbon dioxide</a> each year just in the US, why is it still such a small part of the atmosphere's composition (0.04%)?</p>

CC BY-SA 4.0
2023-11-19T11:10:21.557Z
It used to be 0.028% when I was young...
fraxinus
CC BY-SA 4.0
2023-11-19T15:24:03.693Z
I parsed the title as low in altitude; that is relative CO2 concentration decreases as altitude increases; and got really curious. Was disappointed.
Joshua
CC BY-SA 4.0
2023-11-19T19:59:09.973Z
I'd love an answer about why the CO2 levels are such a small percentage independent of human-made emissions. I suppose it is related to biological or geologic processes over the past few billion years.
bigchief
CC BY-SA 4.0
2023-11-20T08:05:58.180Z
@bigchief feel free to post a question
fraxinus
CC BY-SA 4.0
2023-11-20T23:59:49.787Z
if you want global industrial production that's about 3 billion tons, https://ourworldindata.org/emissions-by-sector and of course that is ignoring manufacturing and electricity production.
John
CC BY-SA 4.0
2023-11-21T04:17:21.610Z
Or, in other words, planets are *big.* ;-)
Peter - Reinstate Monica
CC BY-SA 4.0
2023-11-22T17:47:07.823Z
4th place on a list of dozens of molecules doesn't seem small to me.  But the short answer to the question is... "because the atmosphere is large and dynamic". The CO2 doesn't just "stay there", otherwise concentrations would be much larger near the surface.
f.thorpe
CC BY-SA 4.0
2023-11-23T23:17:40.757Z
@bigchief the short answer is photosynthesis turned co2 into oxygen. when the earth was young CO2 was much higher.
John
<atmosphere><greenhouse-gases>
Why is CO₂ abundance in the atmosphere still small?
techie11
# Why is CO₂ abundance in the atmosphere still small?

(Asked by: username_0 on 2023-11-18)

Given the fact that [industries emit about 1.5 billion metric tons of carbon dioxide](https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions) each year just in the US, why is it still such a small part of the atmosphere's composition (0.04%)?

**Tags:** atmosphere, greenhouse-gases

> **Comments:**
> **username_1**: It used to be 0.028% when I was young...  
> **username_2**: I parsed the title as low in altitude; that is relative CO2 concentration decreases as altitude increases; and got really curious. Was disappointed.  
> **username_3**: I'd love an answer about why the CO2 levels are such a small percentage independent of human-made emissions. I suppose it is related to biological or geologic processes over the past few billion years.  
> **username_1**: @username_3 feel free to post a question  
> **username_4**: if you want global industrial production that's about 3 billion tons, https://ourworldindata.org/emissions-by-sector and of course that is ignoring manufacturing and electricity production.  
> **username_5**: Or, in other words, planets are *big.* ;-)  
> **username_6**: 4th place on a list of dozens of molecules doesn't seem small to me.  But the short answer to the question is... "because the atmosphere is large and dynamic". The CO2 doesn't just "stay there", otherwise concentrations would be much larger near the surface.  
> **username_4**: @username_3 the short answer is photosynthesis turned co2 into oxygen. when the earth was young CO2 was much higher.  

---

## 3 answers

### Answer by username_9 on 2023-11-19. Score: 22 | Accepted answer

The [mass of the atmosphere](https://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html) is 5.1 × 1018 kg, which is 5.1 × 1015 t.

As stated in the edited question,

> industries emits 1.5 billion metric tons of carbon dioxide each year,

That's 1.5 × 109 t.

The mass of Earth's atmosphere is 3,400,000 times the mass of CO2 that industries produces each year in the US.

> **Comments:**
> **username_10**: Is that a US ton that you're using for units?  Google suggests the proper conversion from 1000kg to t would yield 5.6.  
> **username_11**: @username_10 the original article is in metric tons  
> **username_10**: @username_11 I was unaware that the abbreviation of metric ton was also `t`.  Thanks for straightening me out.  
> **username_2**: Hmmm using worldwide CO2 concentration and US CO2 emissions. That's weird.  
> **username_12**: @username_2, I don't think atmospheric CO2 respects our border wall.  
> **username_2**: @username_12: Neither do I. I think it should be worldwide CO2 concentration and worldwide CO2 emissions.  
> **username_13**: @username_2 : the question specifically asked why it is low despite those 1.5 billion tons. This answer shows exactly those 1.5 billion tons in perspective, therefore it answers the question better than if it used global emissions. Even if the answer was expanded to include global emissions, it needs those 1.5 billion tons, so that the OP can see how it relates.  
> **username_14**: An [imperial ton](https://en.wikipedia.org/wiki/Long_ton) is practically the same (at least in this context) as a metric ton (about 2% difference. 1,016 kg). The [short ton](https://en.wikipedia.org/wiki/Short_ton) is further from, but still close (10% lower. 907 kg).  

---

### Answer by username_7 on 2023-11-20. Score: 20

As well as the atmosphere having a lot of mass, there are many processes which remove CO2 from the atmosphere, see the wikipedia article for [the carbon cycle](https://en.wikipedia.org/wiki/Carbon_cycle). Plants sequester it as biomass, some of which ultimately ends up in the soil long-term (the rest is either released again by organic decay or fires). The ocean also absorbs a lot, which is related to the problem of ocean acidification you may have heard of.

It's a delicately balanced dynamic equilibrium that we are disrupting, not a static situation. Think of it like a sink with a half blocked drain that's slowly filling up as you run the water, rather than an empty bowl you're filling up.


---

### Answer by username_8 on 2023-11-22. Score: 1

"Small" is a vague and slippery term. There is now a lot *more* CO2 in the atmosphere than there was a century ago and that change has consequences, especially to climate stability. There is a lot more human emissions - around 40 billion metric tons per year globally now - and that is causing atmospheric concentrations to rise. Those emissions are in addition to natural sources and are moderated by natural processes that absorb and recycle Carbon and overall, so far, natural processes have been taking CO2 back out of the atmosphere at rates greater all the natural CO2 flow into the atmosphere, or the human addition would be making concentrations rise faster than they are.

This diagram shows The Carbon Cycle. It is a few years out of date - the amounts of fossil fuel burning and other numbers will have changed a bit but it gives a good overview of where the carbon is coming from and going to.

[![Global Carbon Cycle](https://i.sstatic.net/st9sM.jpg)](https://i.sstatic.net/st9sM.jpg)


---

