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?
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.
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... (read more)