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I am a science hobbyist and working on a paper to illustrate the impact of CO2 on Global Warming.

Question – What is the Thermal Storage Capacity or Heat Capacity, in joules, of one molecule of CO2 @ 20c/68f/293k. In other words, what is the maximum amount of IR energy/heat that one molecule of CO2 can store at this temperature.

I am aware how to calculate the thermal storage capacity of one gram or one cubic meter of water but don’t quite know how to go about calculating the same for a molecule of CO2.

The mass of one molecule of CO2 is 7.308 x 10^-23g or 7.308 x 10^-26kg and the Specific Heat Capacity of CO2 is 834 at constant pressure (J kg-1K-1)

In essence, I am looking for both the value and the formula for which to use in order to calculate this.

For the cherry on top, how long can it store this amount of energy

Ellsworth
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  • heat capacity is a thermodynamic variable, i.e. an average over the order $10^{23}$ molecules ( in a mole , but that type of dimensions.) there are numbers for this https://www.engineeringtoolbox.com/carbon-dioxide-d_974.html . – anna v May 13 '19 at 14:33
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    Temperature change from increased atmospheric greenhouse gases has nothing to do with their heat capacity. Sunlight absorbed at the surface of the Earth warms the surface, which radiates that heat back towards space. Oxygen and nitrogen are relatively much more transparent to IR than carbon dioxide and methane. As concentrations of the latter increase, more of the IR is reflected back to the surface instead of escaping to space. Think about those extremely thin and light "space blankets"--they have very little heat capacity, but keep you very warm through reflection of your body heat. – Rick Goldstein May 13 '19 at 14:54
  • HI Anna, as opposed to Specific Heat Capacity, i am looking for the Thermal Storage Capacity (Heat Capacity) of just one molecule of CO2 – Ellsworth May 13 '19 at 14:56
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    It doesn't make sense to talk about the thermal properties of a single molecule. I made a plot that might help you see this when I wrote this answer about the equipartition theorem, but I wound up not including the plot in the answer and it might be a day or two before I could adapt it to your question. – rob May 13 '19 at 15:04
  • The CO2 heat capacity is a blind way to think about. It is irrelevant to global warming. – Poutnik May 13 '19 at 15:37
  • @Ellsworth, the CO2 IR absorption band is already saturated, meaning that it is already absorbing practically 100% of the outgoing IR radiation that it can absorb. This means that any further greenhouse effect can only come from a "broadening" of the absorption band. This effect is very small and requires a LOT more CO2 for any substantial broadening. Don't believe everything that you hear from the main stream media, the politicians, or the so-called "experts" who are getting paid by various governments to produce catastrophic climate change reports. – David White May 13 '19 at 16:41

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