CO2 Content of Atmosphere

[arkie87]

So, doing some reasearch, I found that the total mass of carbon dioxide in the atmosphere is ~3e12 tons

Similarly, I was able to find that humans annually release approximately ~30billion tons, or, 3e10 tons per year.

Thus, we release about 1% of the total carbon content of the atmosphere into the atmosphere per year.

Studies have found that concentration of CO2 in atmosphere have risen by 2-3 ppm/yr, which is nowhere near 10,000 ppm (1%) required (admittedly, i didnt convert from mass to moles, but the answer is still correct in order of magnitude).

Obviously, the CO2 doesnt just go into the atmosphere; it can and does dissolve into oceans. However, the statistic i keep finding is that 30-40% of man-made CO2 goes into oceans, whereas, by my calculations, it is more like 99.97%.

Is there an error in my calculations? If not, where does the rest go?

EDIT: found the error. Mass of CO2 increases by 1% per year. Since current concentration is 400ppm, CO2 concentration should increase by 4ppm/yr. It actually only increases by 2-3ppm/yr due to ocean absorption, so the data are consistent.

Edited June 26, 2015 by arkie87

[Tex_NL]

...

Is there an error in my calculations? If not, where does the rest go?

Photosyntheses.

[Kryten]

A lot of that dissolves into the ocean, which is an environmental issues in itself.

[arkie87]

Photosyntheses.

I dont think that can explain this large of a discrepancy... since there is no reason to assume that plants can suddenly matabolize faster just because there is more CO2 in the atmosphere (in addition, i dont know if there is even enough photosynthesizing life on the planet to absorb this much CO2 with photosynthesis). Photosynthesis is limited by sunlight, NOT by CO2 concentration... I think the oceans can absorb much more CO2 than life can...

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A lot of that dissolves into the ocean, which is an environmental issues in itself.

Yes, granted, by i said that myself....

I found the error. Mass of CO2 increases by 1% per year. Since current concentration is 400ppm, CO2 concentration should increase by 4ppm/yr. It actually increases by 2-3ppm/yr due to ocean absorption.

Edited June 25, 2015 by arkie87

[Scotius]

Don't forget that due to increasing global temperature vegetation period is getting longer. Also, plants are growing farther north than before. Forests are encroaching into tundra. And less ice around the poles mean more light for algae - which means polar waters are becoming more productive.

And one more thing - some of phytoplankton mass gets eaten by fish etc. But a lot of dead algae sink to the bottom of the ocean where carbon bound in their cells gets locked pretty effectively.

Edited June 25, 2015 by Scotius

[Tex_NL]

I dont think that can explain this large of a discrepancy... since there is no reason to assume that plants can suddenly matabolize faster just because there is more CO2 in the atmosphere (in addition, i dont know if there is even enough photosynthesizing life on the planet to absorb this much CO2 with photosynthesis). Photosynthesis is limited by sunlight, NOT by CO2 concentration... I think the oceans can absorb much more CO2 than life can...

For millennia there has been a near perfect balance between photosynthesis and respiration. This near perfect balance has always been there and will always be there as long as there is an abundance of life on earth. The amount of CO₂ modern man adds to this equation is only a very small fraction.

[arkie87]

Don't forget that due to increasing global temperature vegetation period is getting longer. Also, plants are growing farther north than before. Forests are encroaching into tundra. And less ice around the poles mean more light for algae - which means polar waters are becoming more productive.

Not sure what you mean by "vegetation period getting longer". Light near poles is a small fraction of total planet area, and fluxes are very low due to angle of incidence, so i'm not sure that that effect is significant.

From https://en.wikipedia.org/wiki/Biomass_(ecology):

Total biomass of carbon on earth is 560e9 tons Carbon = ~1.5e12 tons CO2, which is the same order of magnitude as the mass of CO2 in the atmosphere. Interesting.

Total annual primary production of biomass is 100e9 tons Carbon = ~30e10 tons CO2, which is 10x more than humans create, based on the data in the OP. So by burning fossil fuels, we are having the same effect as a 10% global biomass increase per year.

And one more thing - some of phytoplankton mass gets eaten by fish etc. But a lot of dead algae sink to the bottom of the ocean where carbon bound in their cells gets locked pretty effectively.

This is natural part of the carbon cycle. Unless you can quote numbers (like Gton/yr), not sure if this matters at all. This is just like the dinosaurs becoming oil-- the algae might be replacing them (or perhaps, oil is actually dead algae?).

Edited June 25, 2015 by arkie87

[Shpaget]

The amount of CO₂ modern man adds to this equation is only a very small fraction.

"97 percent or more of actively publishing climate scientists" disagree with you.

http://climate.nasa.gov/scientific-consensus/

[KerikBalm]

Demonstrably false... just these numbers here show the release is 1% of total atmospheric CO2 mass every year

Photosynthesis is limited by sunlight, NOT by CO2 concentration... I think the oceans can absorb much more CO2 than life can...

Photosynthesis may be limited by many things. Water availability for one...

Note that plants can run two types of phot. cyclic and the "z- scheme"

Cyclic can regenerate ATP from ADP+Pi, but it won't fix any carbon.

To fix carbon, you need CO2 and water.

To get CO2, they need to obem their stoma, which also allows much more loss of water to evaporation.

Higher CO2 concentrations allow stoma to be open less.

It also starts to marginalize the advantages of C4 and CAM plants over C3 plants.

Anyway, it is empirically shown that plants will photosynthesize more whan CO2 concentrations are higher.

This is a very good thing, as it leads to a negative feedback loop (more CO2 -> increased pulldown of CO2 by plants/photosynthesizers) which helps keep our atmospheric composition stable.

We'd be more screwed than we already are if this wasn't the case...

Even with this negative feedback loop, humans are powering through it... and while the rate of sequestration of plants may increase.. deforestation and such negates that.

We really really need to transition to solar and thorium breeder reactors.

[AngelLestat]

This doesn´t answer the topic question, but might help to those who seems confused about the co2 natural cycle and the human hand in all that.

This second video is a bit long but explain the same thing with more detail.

[Findthepin1]

Pffft... It is arrogant to believe that man can change the climate.

Thank you for that. I agree fully.

Edited June 25, 2015 by Findthepin1

[PakledHostage]

Thank you for that. I agree fully.

I was making a joke with reference to Rick Santorum's recent comments, hence the [Poe's law] and [/Poe's law] tags.

[sal_vager]

I was making a joke with reference to Rick Santorum's recent comments, hence the [Poe's law] and [/Poe's law] tags.

The tags no one else can see you mean?

I can see them if I try to edit your post, but they aren't displaying, try [noparse][noparse][/noparse][/noparse].

[PakledHostage]

...

[crickets chirping]

Sorry. I was trying to be at least a little bit subtle.

[/crickets chirping]

[sal_vager]

Just ended up a little too subtle

I thought you'd found Jesus...

[arkie87]

"97 percent or more of actively publishing climate scientists" disagree with you.

http://climate.nasa.gov/scientific-consensus/

The 97% quoted here says nothing about the percent of CO2 that man adds to the equation. I would venture to say that 97% of climate scientists agree that the amount of CO2 humanity adds is tiny compared to those exchanged by natural global processes (look it up). However, what 97% are scientists agree on is that despite this small/negligible amount of CO2 released by humanity, its effect is anything but.

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Demonstrably false... just these numbers here show the release is 1% of total atmospheric CO2 mass every year

Photosynthesis may be limited by many things. Water availability for one...

Note that plants can run two types of phot. cyclic and the "z- scheme"

Cyclic can regenerate ATP from ADP+Pi, but it won't fix any carbon.

To fix carbon, you need CO2 and water.

To get CO2, they need to obem their stoma, which also allows much more loss of water to evaporation.

Higher CO2 concentrations allow stoma to be open less.

It also starts to marginalize the advantages of C4 and CAM plants over C3 plants.

Anyway, it is empirically shown that plants will photosynthesize more whan CO2 concentrations are higher.

This is a very good thing, as it leads to a negative feedback loop (more CO2 -> increased pulldown of CO2 by plants/photosynthesizers) which helps keep our atmospheric composition stable.

We'd be more screwed than we already are if this wasn't the case...

Even with this negative feedback loop, humans are powering through it... and while the rate of sequestration of plants may increase.. deforestation and such negates that.

We really really need to transition to solar and thorium breeder reactors.

This source shows some very interesting numbers regarding magnitudes of CO2 absorption

[KerikBalm]

What I meant by demonstrably false, is that its demonstrably true that humans emit CO2 equal to approximately 1% of the total mass of atmospheric CO2 *every year*

1% is not a "very small fraction" in this context.

Findthepin1:

Which of the following is more arrogant?

1) To believe that we can do whatever we want without consequence (with regards to the atmosphere)?

or

2) To believe that we must be careful and responsible (with regards to the atmosphere)?

Personally, I find 1) to be incredibly arrogant, and 2) to be not arrogant at all.

[arkie87]

What I meant by demonstrably false, is that its demonstrably true that humans emit CO2 equal to approximately 1% of the total mass of atmospheric CO2 *every year*

1% is not a "very small fraction" in this context.

That is not the small fraction I was referring to (1% per year would only take 100 yrs to double, after all).

Look at the source I posted above there is orders of magnitude more co2 already dissolved in the oceans, and the exchange rate between ocean and atmosphere is naturally more than ten times what we release per year...

[Shpaget]

The 97% quoted here says nothing about the percent of CO2 that man adds to the equation. I would venture to say that 97% of climate scientists agree that the amount of CO2 humanity adds is tiny compared to those exchanged by natural global processes (look it up). However, what 97% are scientists agree on is that despite this small/negligible amount of CO2 released by humanity, its effect is anything but.

Probably because fossil fuel burning introduces a small net increase in global CO2 levels. The problem is that the fossil fuel burning has been going on for decades and each year, that small net surplus accumulates.

[AngelLestat]

That is not the small fraction I was referring to (1% per year would only take 100 yrs to double, after all).

Look at the source I posted above there is orders of magnitude more co2 already dissolved in the oceans, and the exchange rate between ocean and atmosphere is naturally more than ten times what we release per year...

I read the last posts yours, and I still dont have a clue in what´s your point. Can you detail your conclusion or opinion please?

[arkie87]

Probably because fossil fuel burning introduces a small net increase in global CO2 levels. The problem is that the fossil fuel burning has been going on for decades and each year, that small net surplus accumulates.

So then you acknowledge that 97% of scientists agree that mankind is adding a very small amount of CO2/yr compared to what is exchanged per year naturally?

The carbon cycle goes through cycles (it is not locked in an equilibrium, contrary to popular belief), such that adding a small fraction more CO2 per year might just increase how much is stored per year.

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I read the last posts yours, and I still dont have a clue in what´s your point. Can you detail your conclusion or opinion please?

My point is that the ocean might be able to absorb the extra CO2 humans put into the atmosphere, given that it already contains much more carbon than the whole atmosphere contains, and contains 10x more carbon than all of the fossil fuels on the planet (according to the source).

Just because we add 30Gton CO2 per year into the atmosphere, and the atmosphere naturally exchanges 10x that with the ocean, doesnt mean those natural exchange rates wont change. If we release more CO2 into the atmosphere, the ocean will absorb more CO2 and reach a new equilibrium.

[Kryten]

The carbon cycle goes through cycles (it is not locked in an equilibrium, contrary to popular belief), such that adding a small fraction more CO2 per year might just increase how much is stored per year.

That'd be a perfectly reasonable thing to say, about 300 years ago. In the interim we've actually tried this, and the increase in absorbtion hasn't been enough to prevent significant rise in atmospheric levels. You might've heard about it.

[ZedNova]

If we release more CO2 into the atmosphere, the ocean will absorb more CO2 and reach a new equilibrium.

Not if those photosynthetic organisms are dying from increased temperatures, abnormal weather, or changes in the Oceans pH level due to melting glaciers, acid rain ect.

There are many other effects you are overlooking here, climate change is a very complex phenomenon.

Edited June 26, 2015 by ZedNova

[arkie87]

That'd be a perfectly reasonable thing to say, about 300 years ago. In the interim we've actually tried this, and the increase in absorbtion hasn't been enough to prevent significant rise in atmospheric levels. You might've heard about it.

Most sources say between 30-40% of CO2 is abosrbed by the ocean. It takes concentration gradients for diffusion to occur. If we stopped burning all carbon now, there is no reason to assume the earth wouldnt return to it's pre-industrial revolution ppm.

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Not if those photosynthetic organisms are dying from increased temperatures, abnormal weather, or changes in the Oceans Ph level due to melting glaciers, acid rain ect.

There are many other effects you are overlooking here, climate change is a very complex phenomenon.

Yes, it is definitely very complex.

What is the pH of melting glaciers? Is it not 7? Just looked up pH of ocean, which is apparently 8.1, and not 7.... interesting....

But yes, the ocean will continue to absorb CO2 even if all living things in it die, since CO2 dissolves in water...

[YNM]

Didn't the OP stated a small impact of modern humans to increase in CO2 level, biologicaly ?

For other things like man-made machines etc. that's a different story.