Environmental Impact Face-off: Cows vs. Soda

I’ve been digging into the incredibly broad world of climate impact and the organizations working to address it. I read that Climeworks is working to sell captured carbon dioxide to the carbonated beverage industry. That got me thinking: carbonated beverages have CO2 in them, so when you crack the can (and when you burp) all the CO2 is going back into the atmosphere. Then, a friend shared an article about a British company working on collecting methane from cow’s burps. (It turns out 95% of methane from cows comes from their burps; not what I thought!) So how do cow burps and people burps stack up in their impact on climate change?

I’m pretty sure that cows are a much bigger impact, so let’s do some quick math to assess that.

Methane is 28 to 84 times more damaging to the environment than CO2 (depending on the time-scale). Let’s use the lower bound. From the cow-burp article there are about “1.5 billion cows on the planet”. The world population is 7.8 billion people. Does a single cow, on average, produce more than twice the volume of methane as an average individual’s beverage carbonation in a year?

“A single cow on average produces between 70 and 120 kg of methane per year” reports an article at phys.org. Taking the lower bound, an average person would need to consume (and release) more than 35kg of CO2 in a year.

Global beer consumption in 2017 was “approximately 186.72 million kiloliters” which comes out to 24L per person annually. Carbonated soft drink consumption, worldwide, in 2017 totaled “202,763.17 million liters”, which averages 26L per person annually.

“The maximum amount of CO2 that can be dissolved in water is 8 g/L” (Ibrahim M. Abu-Reidah, in Trends in Non-alcoholic Beverages, 2020). Looking just at beer and soda (presuming those make up most of the carbonated beverages), then on average a person’s annual consumption (and release) can’t be more than 400g of CO2. Much less than the equivalent of 35,000g of CO2 produced by a cow.

Phew! I might have to stop eating cheese, but at least I can still drink La Croix.

All that is is jest, of course. But this did get me pondering a number of things:

  • If Climeworks is capturing CO2 and then selling it to the carbonated beverage industry, is it really carbon-capture? (Industrial plants already capture CO2 and sell it to the beverage, fertilizer, and other industries.)
  • The cow-burp article says that the device captures methane and releases CO2. (I wonder how do you go from CH4 to CO2 without heat.) It’s not carbon-capture because it releases it, but it is reducing green house gas damage because CO2 is so much less damaging than CH4. If we can’t capture the carbon, can we reduce the damage of the worst offenders?
  • While methane is much more damaging, it’s concentration is still 200 times less than CO2. But looking at the change since baseline, it’s about 100 times less. I need to spend more times digging into these things to understand Global Warming Potential (GWP). From what I’ve read CO2 is by far the greater issue.

And maybe, just maybe, we can reduce methane emissions from cows by feeding them by-products from beer making (source, in Dutch).


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