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Comment by pkphilip | Hacker News Reader

Livestock is grown in parts of the world on stuff which cannot be sold or which grows on its own - example: grass etc. How in the world is lab grown meat going to compete with that in terms of efficiency, CO2 emissions etc?

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Because making calories from livestock that grazes on grass is terribly inefficient, which is why we:

1. put them into small boxes usually, which creates a big nitrogen problem (mixing urine and shit is bad news)

2. feed them other stuff, usually made of soy which is grown in burned down rainforests

3. grow the grass with artificial fertilizers (made out of natural gas) and use pesticides, which also requires gasoline (to power machines)

If we're not even talking the CO2e emissions including methane, or the land use, pollution etc then for each calorie of cow you produce you could also create 25 plant based calories. The problem is a lot of people don't want to (only) eat plant based stuff, so we are coming up with ways to manufacture something in a lab that tastes similar to meat.

There are several ways to beat the natural process, which is really not that efficient at all and involves a lot of negative effects on the environment even if we disregard animal suffering. I mean, it does make sense if you think about it from first principles: a cow doesn't only turn grass into meat and milk, but also needs to move, to reproduce, it needs to power its brain, etc. We should be able to save a lot of energy in a lab not doing all those things and become vastly more efficient than what the cow does. And we could build a mass production process that is way more easier to manage than cattle and slaughterhouses. That is the theory.

The vast, vast majority of meat is grown on land which we can put to better use. The tiny amount of livestock that can be put on a natural rotational grazing system in a sound way making use of land that has no better purpose is so, so small, we shall be eating one burger a year at most from that system.

Another potential advantage of cultured cells is higher amino acid digestibility/DIAAS[1] scores, which is generally much higher in whole animal based foods , for example chicken breast is rated a 1.08, eggs a 1.13, Soy a .91, chickpeas a .83 and Tofu a .52, with each being limited in some amino acids.

Vegetable Protein isolates/processing combinations can bring this up a bit, but processing can have varied effects on availability defending on how it's performed, making something with a high DIAAS score without processing or additives to taste and act like meat ideal. "Literature suggests that the extensive processing needed to obtain protein isolate might induce molecular alterations, making the protein more resistant to digestive enzymes and decreasing its protein nutritive value."[2]

[1]https://en.wikipedia.org/wiki/Digestible_Indispensable_Amino...

[2]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9552267/

You have to explain to me what this:

> Livestock is grown in parts of the world on stuff which cannot be sold or which grows on its own - example: grass etc.

Has to do with CO2 produced from raising livestock? I can't connect the two in my head, there's some missing information here I don't have.

The argument seems to be that livestock only eats stuff that would have been grown anyway and therefore has no effect on CO2 emissions. But I think this is wrong for two reasons:

1. The premise is false. Quite a lot of farmland is devoted to growing feed grains. See https://www.ers.usda.gov/topics/crops/corn-and-other-feed-gr... If we had less livestock, we could either grow human-edible crops instead (with much less energy per calorie expended) or leave these fields fallow.

2. It ignores the fact that some livestock (cows) converts feed into methane, which has a disproportionate climate impact—more methane than if the same grain had been produced, but not consumed by a cow. Admittedly, this is less relevant when we're talking about lab-grown chicken meat. But GP's point was about livestock generally, so this is worth considering.

There are at least three categories of land. Land that can be mechanically harvested, land that can be harvested by animals, and land that's neither.

If we stop growing beef on the second category of land that's not suitable for combines but is suitable for bovines, well, that could represent a net loss of food.

Haven't you heard the argument that livestock raising releases methane/CO2 etc?

The argument? It's not an argument - livestock does produce CO2. It is a fact. I don't eat meat partially for this reason.

I still have no idea what it means with regards to your original statement.

Haha, seems like OP randomly chose the wrong argument from the wrong pamphlet. Yes, livestock produces CO2. The part about it feeding on grass is a typical argument against purely plant diet, based on the assumption that if we stop eating meat we'll starve, because we cannot produce enough plant-based food, and meat production helps, because we can turn otherwise useless plants (grass), growing on otherwise useless land, into something we can eat.

> because we cannot produce enough plant-based food,

Livestock eat more plant based food that we will ever need though, it's the most inefficient food production for a reason.

Most livestock in the west is kept in poor conditions and fed grains. Fully grass-fed meat is not common here. Also, it takes about 4 years for a cow to be fully grown and ready for slaughter. How little CO2 and methane do you imagine a cow produces during that time?!

Meat is the most inefficient food you can buy today, the landmass used is massive. Grass, corn, soy... which produce a ridiculously small amount of final product.

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