# How Much Dry Ice is 100 ppmv of Atmospheric CO2?

I once read this interesting post at Judith Curry’s blog, Climate Etc. It’s a rather fanciful scheme to precipitate CO2 out of the air in Antarctica and store it as snow, with the process being powered by wind turbines. I thought a better energy source for this would be nuclear power and even commented on it. Since then  I’ve been intrigued by the concept of using nuclear power in Antarctica to freeze and store CO2.

So I thought I’d do some calculations to get some idea of the scale of such an operation. I picked 100 ppmv as a good round number for how much CO2 to store (pre industrial was below 300 and is now 400) and converted it to volume of dry ice. I came up with 760 cubic kilometers or 182 cubic miles. A huge undertaking to be sure, but it does not seem totally out of the range of possibility. Notes on my calculations are below the fold.

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Math! How much CO2 by weight in the atmosphere?

According to wikipedia (CO2):

As of January 2007, the earth’s atmospheric CO2 concentration is about 0.0383% by volume (383 ppmv) or 0.0582% by weight. This represents about 2.996×10^12 tonnes, and is estimated to be 105 ppm (37.77%) above the pre-industrial average.

CO2 concentration by weight is obtained by the formula below:

0.0383 V% x [44.0095/28.97] = 0.0582 m% CO2

whereby molar mass=44.0095 g/mole and mean molar mass of air=28.97 g/mole

Then, to obtain the total mass of CO2, via wikipedia: according to the National Center for Atmospheric
Research, “The total mean mass of the atmosphere is 5.1480×10^18 kg.

Thus, the total weight of CO2 = 0.0582% x 5.1480 x 10^15 tonnes
= 2.996×10^12 tonnes.

https://micpohling.wordpress.com/2007/03/30/math-how-much-co2-by-weight-in-the-atmosphere/

The density of dry ice varies, but usually ranges between about 1.4 and 1.6 g/cm3 (87 and 100 lb/cu
ft)

METRIC UNIT CONVERTER

1 g/cm3 = 1 ton/m3

Density of dry ice is 1.5 tonne/m^3

1 km^3 = 1000m x 1000m x 1000m = 1000000000 m^3 = 10^9 m^3

100 ppmv is about 38% of total CO2 in 2007. Total tonnes was about 3×10^12. 0.38 x 3×10^12 =
1.14×10^12 Tonnes. The density of dry ice varies, but usually ranges between about 1.4 and 1.6 g/cm3
(87 and 100 lb/cu ft)

METRIC UNIT CONVERTER

1 g/cm3 = 1 ton/m3

Density of dry ice is 1.5 tonne/m^3 = 1.5×10^9 tonne/km^3.

1.14×10^12 tonnes / 1.5×10^9 tonne/km^3 = 760 km^3. 760 km^3 x 0.24 mile^3/km^3 = 182 mile^3.

## 4 thoughts on “How Much Dry Ice is 100 ppmv of Atmospheric CO2?”

1. Will Janoschka says:

Interesting,!
The atmospheric ‘volume’ is one third nightside as that compared to sunside. Just what may some 300 ppmv mean when compared to ‘volume’? The chemists have it correct. 300 CO2 molecules for one million atmospheric molecules, quite independent of ‘volume’.
Why not listen to humble ‘chemists’ that have some clue, rather than to self appointed ‘atmospheric physicists that have ‘not a clue’, and still live in mommies basement?

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1. Canman says:

Looking over my calculations, I think I may have forgot to factor in 100 parts instead of 383 parts! That means that all the huge results of my subsequent calculations should only be about a quarter as large. I’ll have to look into it.

Liked by 1 person

1. Canman says:

Just looked into it and no I didn’t:

100 ppmv is about 38% of total CO2 in 2007. Total tonnes was about 3×10^12. 0.38 x 3×10^12 =
1.14×10^12 Tonnes.

Drats! Now I can’t reduce my results by a factor of four. It looks like I won’t be submitting any proposals to the Donald.

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2. Will Janoschka says:

“Looking over my calculations, I think I may have forgot to factor in 100 parts instead of 383 parts! That means that all the huge results of my subsequent calculations should only be about a quarter as large. I’ll have to look into it.”

Seems now that you are ‘thinking’. How can I help with your ‘thinking’, rather than some believing in others?

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