Update 31.12.2015: In a closed system of water and air, how does the concentration of CO2 change as a function of temperature, in the gas phase?

What is the graph of carbon dioxide ($\ce{CO2}$) content in the air in a compartment consisting of 80 percent air and 20 percent ocean sea water as a function of temperature, in the temperature range 0 to 60 degree Celsius?

Example but not the complete answer:

enter image description here

As can be seen from the graph above, increasing the temperature of the water will cause the water to release more carbon dioxide ($\ce{CO2}$) in to the gas phase. This happens for most gases as can be seen from this page:


What I am interested in is to see a graph of the percentage, or how to put it, of carbon dioxide ($\ce{CO2}$) in air as a function of temperature.

In other words, what does the plot of:

$$\%\ce{CO_2} \text{ in air (temperature)} = \frac{\text{kilogram } \ce{CO_2} \cdot 100 %}{\text{kilogram air}}$$

look like in the gas phase in a compartment consisting of 20 % sea water and 80 % air as a function of temperature?

Ideally the compartment should consist of a column with the height upwards of average atmosphere thickness on planet earth filled with air, and a depth downwards with the average depth of sea water also at planet earth filled with sea water. But this is probably not feasible. Therefore the simplifcation 80 percent air, 20 percent sea water. If sea water is too complicated I am also satisfied with an answer with pure water.

The definition of air without water steam in volume percentages:

Nitrogen $\ce{N_2}$ = 78.08
Oxygen $\ce{O_2}$ = 20.95
Argon $\ce{Ar}$ = 0.934
Carbon dioxide $\ce{CO_2}$ = 0.036
Neon $\ce{Ne}$ = 0.00182
Helium $\ce{He}$ = 0.00052
Krypton $\ce{Kr}$ = 0.00011
Hydrogen $\ce{H_2}$ = 0.000050
Xenon $\ce{Xe}$ = 0.000009
Ozone $\ce{O_3}$ = 0.000001
Radon $\ce{Rn}$ = 0.000 000 000 000 000 006

Edit 18.4.2015: I will try to clarify the question:

Does an increase in temperature cause an increase or decrease in the carbon dioxide (CO2) content in the atmosphere?

Edit 22.4.2015: According to engineering toolbox dot com, the four most common gases in the atmosphere have the following solubilities in water:

Nitrogene solubility in water as a function of temperature Oxygene solubility in water as a function of temperature Argon solubility in water as a function of temperature Carbon dioxide solubility in water as a function of temperature

Related question: https://mathematica.stackexchange.com/questions/80586/how-can-i-get-the-solubility-value-of-nitrogen-in-water-at-10-degree-celsius-wit


1 Answer 1


Simple, partial pressure of $\ce{CO2}$ is misleading.

$\ce{CO2}$ actually reacts with sea water: $$\ce{H2O + CO2 -> H2CO3}$$ which then ionizes: $$\ce{H2CO3 -> H+ + HCO3-}$$ which lowers the pH of the sea water (making it more acid).

In previous high $\ce{CO2}$ periods, $\ce{CaCO3}$ came out of sea water making limestone and marble rock formations geologically. $\ce{CO2}$ at high pressure is responsible for other side effects, also killing fish, and microbes, damaging coral reefs and generally messing up ocean life.


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