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Like a lot of folks eating primarily or only plants, I dislike eating animals because I empathize with animals and feel bad about their suffering from raising them for food.

That said, how much of the suffering involved in meat consumption actually comes from the animal whose meat is consumed?

What I'm thinking about is that eating animals is O(10) times less efficient at providing calories than eating plants. This suggests that if more than 0.1 units of suffering (assuming the animal being eaten suffers 1 unit) are produced in the production of plants for food, then the suffering caused by eating meat is dominated not by the suffering of the animal being eaten but by the suffering caused in order to produce the food.

Obviously some of this is going to be hard to pin down. For example, depending on how you weigh the suffering of insects and how much pesticides are used to grow feed stock of the meat being consumed may cause wild swings in estimates, but I'd nonetheless be interested in seeing what models people have of how much suffering is caused. This might also make a suffering-oriented case for better meat choices among those who eat meat anyway. For example, maybe organic beef causes O(100) times less suffering than conventional beef because 100 times fewer insects suffer in its production?

So, any thoughts on this, what I might call the "iceberg" of suffering caused by eating meat?




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If you're only considering suffering or assume life in the wild is net negative, and also considering wild animal suffering that you might reduce because you eat certain things (not just because you abstain from others), these may be helpful (although they may be helpful generally):




I recently did a quick calculation just to get an idea of how many wild animals would be affected by farming land vertebrates (in good or bad ways):

  1. 50% of the world's habitable (non-barren, non-glacial) land is used for agriculture, and 77% of that is used for farmed animals, including farmland, grazing land and land for feed production, so 38.5% of habitable land is used for farmed animals (Our World in Data).
  2. Each of wild mammals alone, wild birds alone and wild reptiles alone outnumber farmed land vertebrates at least a few times and possibly 1000x (Brian Tomasik), and so together probably outnumber farmed land vertebrates 10x-1000x. Therefore, naively combining the above estimates with this one, it seems that farming affects 3x-500x as many wild land vertebrates as it does farmed land vertebrates by area. (The reptile upper bound seems high to me, but I also live in Canada, where it's cold and I rarely see reptiles.)
  3. Wild land invertebrates of course outweigh farmed land vertebrates even more in number and so would be affected in much larger numbers, although it’s not clear they deserve more weight overall.

Nice answer. :) It's worth noting that many wild animals in agricultural lands might not be affected too much by the agriculture (well, at least in the case of low-density pasture grazing; I guess crop cultivation changes land's flora and fauna more radically).

Just counting reptiles in tropical regions and assuming no reptiles anywhere else in the world, my article estimates 10^11 to 10^13 reptiles, compared against a bit more than 10^10 land farm animals. So I'm not sure if the 1000X number is too high. One reason it might be too high is that maybe when people study animal densities, they choose the most animal-dense places to sample from.

That's a good point about how much they are affected. If only around 10x as many wild land vertebrates are affected, I think it's pretty reasonable to believe that the effects on farmed land vertebrates are more important without thinking too much about the specifics, given how bad chicken lives seem to be on average. However, if you think a decent share of animal suffering is in dying, then wild vertebrate population effects could easily dominate. I think it's suspicious at around 100x, and would want to see more details about the magnitudes and directions of the effects on wild land vertebrates. This is all before considering land invertebrates, but for someone with a lot of moral uncertainty about their moral weight, maybe the most sensible thing to do would be to also support an effective insect welfare/anti-insect farming charity. You could make sure you're net positive in expectation for both land vertebrates and land invertebrates with a portfolio of interventions. And then we also need to look at aquatic animals.   Good to know about reptiles. That high end was surprising to me, given that I hardly ever see reptiles (in Canada, though!).
Yeah, I mainly only see snakes and turtles in New York state. This figure shows four reptile species in a tropical forest in Puerto Rico, and three of them are anole lizards. The fourth, Sphaerodactylus klauberi, also seems to be quite small. I'm unsure whether an anti-insect-farming charity can offset potential wild-invertebrate harm from reducing beef/etc production (though it's worth remembering that the sign of those side effects of meat isn't super clear). Rowe (2020) says: "There are currently between 79 billion and 94 billion insects alive on farms globally on average on an average day." The number of arthropods on a single hectare of pasture can be in the hundreds of millions, so 1000 hectares of arthropod-dense pasture could have as many arthropods as all insect farms. (BTW, apparently a beef cow tends to require a bit less than 1 hectare of pasture.) However, most of these pasture arthropods are mites and springtails, which are vastly smaller than mealworms, crickets, or black soldier flies, so probably each mite or springtail matters several times less (maybe tens or hundreds of times less?) than a farmed insect. BTW, there may be ~10^10 = 10 billion nematodes per hectare of soil. Yeah. I like to separate beef from chicken in these discussions because I worry about people taking away a message like "the side effects of meat in general are large and unclear, so don't worry too much about eating meat", given that until we have more clarity on the side effects, it seems good to err on the side of not causing lots of chicken suffering. I feel less worried about people feeling uncertainty regarding beef because it's so much less bad in terms of direct suffering per calorie of food (though beef cows still endure some awful things, like castration and slaughter) and because in some cases it's plausible that beef reduces net wild-animal suffering (though I remain pretty uncertain about that).

As Michael notes, there can also be reductions in suffering that result from these side effects of meat consumption, unless one's morality is purely focused on harm caused by humans and doesn't count natural harms prevented by humans. These good and bad side effects on wild animals seem important, though in many cases it's not obvious what their net balance is. For example, does crop cultivation reduce or increase total wild-animal suffering? How about pasture grazing? Climate change? Eutrophication? I've attempted to analyze the net impacts of these things in various articles on my website, but coming to any firm conclusions is difficult. Because of the uncertainty regarding the wild-animal side effects, it seems reasonable to err on the side of reducing the much more certain harm to farm animals, although in the case of beef production, I think the ratio of (wild-animal side effects) / (harm to farm animals) is large enough that we should also give significant attention to the wild-animal side effects as best we can estimate them.

The exact ratio of (wild-animal side effects) / (harm to farm animals) will depend a lot on how much weight you give to brain complexity. If you simply count number of individual animals affected, as Michael explains, these ratios will be quite large (especially if invertebrates are included).

Organic crop production sometimes uses insecticides, and other organic methods of pest control can be painful as well (such as introducing natural predators/parasites/pathogens), although some organic pest-control methods seem like they'd cause less bug suffering, such as crop rotation, selection of plant hybrids to use, and harvest timing. In addition to pest control, crop cultivation kills lots of bugs via crushing (during tilling, planting, harvesting, etc), and there are lots of other side effects that growing plants has on bug suffering, both good and bad. So I certainly wouldn't use a ratio of ~100 for the difference between organic and non-organic crop production. It's not even clear to me if organic is better than non-organic.

Do you expect pest control and crop cultivation deaths to cause more suffering through the direct harms than they prevent by reducing populations?

Maybe since the populations have such high growth rates, they're mostly limited by the carrying capacities, so pest control might have almost no effect on population size. Similarly, the main population effects from crop cultivation would be through how much food is available, not the cultivation deaths.

A main reason I'm uncertain about the sign of crop cultivation is that I don't know if it reduces total invertebrate populations. Especially when irrigation and fertilization are used, crop net primary productivity can be somewhat higher than that of native grassland, although I also get the impression that farm fields can also be less rich in soil fauna than native ecosystems (maybe partly due to pesticides?). I assume that insecticides are usually pretty effective at reducing populations of target (and probably at least some non-target) insect species. OTOH, crops fields can sometimes breed much larger insect infestations than would occur in a wild ecosystem. Berryman (2008): "growing extensive monocultures of a particular plant genotype may provide a huge amount of highly susceptible food for insects that feed on that crop, and/or may create an environment that is less hospitable for some of the natural predators and parasites that attack them." That said, I feel like wild plants can also have big insect infestations. I've seen hundreds of aphids on a single wild plant near my house.

Brian Tomasik wrote this article on the amount of direct suffering caused by various animal foods. In general, meat from large animals like cows causes less suffering than meat from small animals like chicken and fish, since fewer animals are needed per unit of meat. Eating insects may also be a bad idea for this same reason.

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