Quantifying CO2 generated/released by the soft drink industry and breweries

Question

I need some help in developing a method by which to calculate how many tons of "evil" $\ce{CO2}$ are routinely being released into the atmosphere SOLELY due to our beverage addictions, notably beer and soft drinks. I realize that not all manufacturers and products are consistent in their carbonation levels, and that an average probably has to be applied industry-wide (unless individual companies are required to record and publish such data) per unit measure or monthly/annual volume output.

Is this the proper forum to ask such a question? If not, suggestions on where else I go?

On a previous post I got part of the answer, relating to an individual 12 oz can, or 1 liter, but I'm wondering if there is an easier way in which I can go about plugging weekly, monthly or annual volumes of beverages into formulas which will yield the results I'm looking for, notably a discussable unit of measurement in tons or ? I'm willing to do all the numbers work once I'm pointed in the right direction.

I'm not sure if anybody's ever thought about this before, because I've never heard it discussed. But if, according to some environmentalists, we should all watch our carbon footprint (and I'm not debating that here), then it seems like the most logical place to start would be with our hundreds of millions of daily beverage choices? Isn't it?

Answer 1

The xkcd What If? blog, by Randall Munroe, addressed a similar question. He states the result better than I can.

For most of the history of civilization, there were about 270 parts per million of carbon dioxide in the atmosphere. In the last hundred years, industrial activity has pushed that number up to 400 parts per million.

One "part per million" of CO₂ weighs about 7.8 billion tons. A can of soda contains in the neighborhood of 2.2 grams of CO₂, so you would need about 450 quadrillion cans of soda. That's enough to cover the Earth's land with ten layers of cans.

• Randall Munroe - xkcd What If? #88:Soda Sequestration. http://what-if.xkcd.com/88/

For further perspective, each breath of a healthy adult male involves about 500mL of gas exchange. The air is, on average, 0.04% CO₂ prior to inhaling. Exhaled air contains between 4 and 5 percent carbon dioxide, I'll call it 4.04% for a nice, round 100-fold addition. The mass of 500mL of air is about 0.6g, and though it will be slightly more dense with the added carbon dioxide, I'll assume that it remains at that mass for simplicity's sake.

So 4% of the 0.6g is CO₂ that was added to the atmosphere by a single adult male breath. That's 0.024g. About 90 breaths add as much CO₂ to the atmosphere as the carbonation in a can of Coke. Where does the additional carbon in those breaths come from? The Coca Cola itself, of course.

The sugar in the can of Coke (39g) contains about 16g of carbon atoms. After being metabolized, that turns into 57.2g of carbon dioxide. Not considering any of the energy required to harvest, process, or transport the sugar, that's still 26 times a much carbon dioxide going into the atmosphere from the calories in a can of Coke as opposed to its carbonation.

To put it more succinctly, the CO₂ output from the carbonation in Coke could be completely offset by reducing overall caloric intake by 6 calories per can.

Answer 2

The xkcd information is interesting, but doesn't really answer the question, which is about how much CO2 is produced by the industry. For that, we need to understand a key difference between fermented and non-fermented carbonated beverages.

Non-fermented carbonated beverages are carbonated using CO2 provided by industrial gas companies who capture this CO2 from waste exhaust of other industries and clean it up. For example, hydrogen production by steam-reforming of methane produces high CO2 concentration gas as waste, as does the ethanol fuel fermentation industry. So the non-fermented beverage producers aren't generating CO2. They're just delaying its release into the environment from other processes.

The fermented beverages are quite different, in that CO2 is a product of the conversion of sugar to ethanol by the yeast (or in a few cases bacteria). Most of this CO2 leaves the tank and doesn't remain in the beverage as carbonation, so the amount of carbonation in the beverage isn't the number to focus on. Instead, we can estimate the CO2 generated by assuming that most of the fermentation operates anaerobically at a typical product ratio of 1 mole CO2 per mole ethanol.

According to the WHO, Americans drink about 5 liters or so of pure alcohol per capita per year, which we can round up to 100 moles (5.9 L) for convenience. Assuming roughly 350 million people in the US, we have total consumption as 35 B moles of CO2. 35 B moles of CO2 is about 1.5 million metric tons of CO2 produced during fermentation of the alcoholic beverages that are consumed in one year by Americans.

For comparison, a typical car produces about 4.5 metric tons of CO2 per year as exhaust, according to the EPA, so the beverage fermentation industry is equivalent to about 350,000 cars.

Answer 3

The answers so far leave out any Co2 generated by the electricity consumed in refrigeration of the beverages (which in a retail outlet may be as long a a week or more) and any Co2 produced by the electricity used in the manufacturing process. World wide this gets a bit tricky! I couldn't begin to know how to work that out. There's also Co2 emitted in the transport of the ingredients to the manufacturing plant and of the finished product to market as well. Also I am not sure that Co2 being used for soft drink is always the bi product of another already existing project, and perhaps not even that frequently, in 2016 I think this was still developing technology (see)https://www.abc.net.au/science/articles/2001/11/29/405835.htm An article from Time Magazine in 2008 if skim read seems to suggest this technology is in wide use, however if read more closely, it doesn't actually. http://content.time.com/time/specials/2007/article/0,28804,1730759_1731383_1731989,00.html