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Wed Apr 8, 2020, 01:31 PM

A Back of the Envelope Calculation of the Mass of Carbon Dioxide in Earth's Atmosphere.

Disclaimer: It's not actually "back of the envelope;" it's "in the spreadsheet."

Last night I started to write a post about a paper published yesterday in the scientific journal ACS Sustainable Chemistry and Engineering on the subject of nature of lignins. Lignins are often discussed in the scientific literature as a source of chemicals, particularly aromatic chemicals, to replace those that are currently provided by the dangerous fossil fuel petroleum. Lignins are highly complex structural polymers found in all terrestrial higher plants in the form of "lignocellulose." They are readily available as a side product of the manufacture of paper, which is largely derived from cellulose extracted from lignocellulose, including the much now appreciated, in the days of Covid, toilet paper. (Save Trees: Bring on the bidets!)

In writing that post, which will come along separately at some other time; I found myself asking the question of how much carbon dioxide could be sequestered as products if we began to use lignin as something other than a combustible fuel (which is how it is largely utilized now), that is, began to use it to make industrial structural polymers and other industrial products. The next question I asked myself is how significant this much sequestered carbon would be. This led me to ask a question that somehow I've been overlooking for some time, which is "what is the mass of the carbon dioxide in the Earth's atmosphere?"

Currently the concentration of the dangerous fossil fuel waste carbon dioxide in the atmosphere, as of this writing, is about 416 ppm. This number is a dimensionless number that actually represents the mole fraction which is a representation of the average number of atoms in the entire atmosphere that are carbon dioxide. It means that if one were to physically count one million atoms in the Earth's atmosphere on average 416 of them would be carbon dioxide molecules and 999,584 of them would be something else, other molecules, nitrogen molecules, oxygen molecules, monoatomic argon molecules and so on. In order to extract these carbon dioxide molecules from air, we would still need therefore to reject 999,584 molecules in the process of collecting the 416 CO2 molecules, a prodigious task. Besides dumping carbon dioxide on all future generations in the orgy of consumption my generation undertook from the late 1960's to the current day, we also dumped entropy, which in many ways is a more serious problem, especially as it extends beyond carbon to pretty much every other element in the periodic table.

The average molecular weight of air is taken as 28.97 gram/mole. The mass of the Earth's atmosphere, taken from a widely referenced paper, The Mass of the Atmosphere: A Constraint on Global Analyses (Kevin E. Trenberth, and Lesley Smith, Journal of Climate, Vol 18, pp 864-875), is 5.148 zetagrams (5.148 X 10^18 kg). From these figures we can see that the number of moles of air on this planet is 177.7 Examoles of air. (1.777 X 10^20 moles). Since the fraction of these moles that are moles of carbon dioxide is 416 ppm = 416/1,000,000 = 0.000416 is follows that the number of moles of carbon dioxide is 73.29 Petamoles (7.329 X 10^16 moles). The molecular weight of carbon dioxide is 40.01 grams/mole. This means that the Earth's atmosphere contains 3.253 Exagrams of carbon dioxide. Translated into metric tons, this amounts to 3.253 trillion tons of carbon dioxide.

About 200 years ago, the world began to abandon so called "renewable energy" because most people while most people lived short miserable lives of dire poverty, even more so than today, and the world was running out of forests to destroy to provide wood for rich people as well as to provide scrapings for the poor. At that time, the concentration of carbon dioxide was probably somewhere in the neighborhood of 270 ppm. The fraction that 270 ppm represents of today's concentration is 270/416 = 0.646.

It follows that the amount of carbon dioxide that would need to be removed from the atmosphere to reach pre-industrial levels is 1.15 trillion tons.

If we take 1820 as the year that the coal industry really began to take off because of the invention of the steam pump to drain coal mines so children could labor in them without drowning, we see this process of utilizing dangerous fossil fuels to avoid the poverty associated with so called "renewable energy" we can calculate that the average addition per year since 1820 was on the order of 5.76 billion tons per year.

In 1820, one could be excused for thinking this was a good idea. Atomic theory was still in its infancy (and not completely accepted), the nature of light was only partially understood and its relationship to energy even less so; indeed the concept of energy itself was largely esoteric and was a subject primarily of academic and not general interest.

However, since 1959 fairly precise records for carbon dioxide concentrations have been kept at the Mauna Loa carbon dioxide observatory, when mean the concentration of carbon dioxide was 315.97 ppm, we can see that since 1959 the concentration has risen by nearly exactly 100 ppm. From the above numbers, we can see that the amount of carbon dioxide dumped in the age of baby boomers, that awful generation to which I belong, amounted to about 782 billion tons of carbon dioxide. This means the average amount of carbon dioxide dumped since 1959 was 12.8 billion tons per year.

For perspective, we are now dumping, according to the most recent figures, about 35 billion tons per year with another 8 to 10 billion tons per year additional arising from land use changes, the conversion of wilderness to farm land, the conversion of farm land to suburbs with shopping malls and McMansions, the conversion of wilderness to strip mines etc, etc, etc...ad nauseum...including the conversion of wilderness to industrial parks for wind turbines that have had zero success in addressing climate change, are having zero success in addressing climate change and will continue to have zero success in addressing climate change.

Things are getting worse, not better.

If you're a baby boomer like me, don't worry, be happy. Just go on prattling about how wonderful wind farms and solar cells and Elon Musk's cobalt laced electric cars are. Don't forget to throw in illiterate comments about how dangerous nuclear energy is, neglecting of course to compare it do anything else in terms of destructive power; destructive power, I note, that unlike the mindless assumptions provided by your fervid imaginations about nuclear energy, that is actually being observed rather than imagined in the case of the unaddressed and continuously rising use of dangerous fossil fuels.

None of this is your problem, you'll be gone soon enough. It is the vast problem on an unimaginable scale for all those millennials you like to condescend in your bourgeois nobility and in fact, for every generation after theirs.

I'm a dissident, by the way, with respect to my views on the millennial generation. From my perspective, I expect great things from them, but even they do not prove to be a "greatest" generation as I expect they will, they could hardly be worse than we were.

History will not forgive us, nor should it.

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