Thanks, spindoctor! What an interesting series of articles. (The author is Ward
Clark. The other author you're thinking of is
Steven Davis.)
If you get past Clark's vitriol, he provides some useful data. The "two vertebrate deaths per square foot" figure seems almost certainly on the high end for most crops, but others are probably not orders of magnitude less.
My first reaction was the typical one that vegetarians raise: That it takes many times more soybeans to feed livestock than to eat tofu directly. However, Clark is probably correct that "A pound of wild venison (net cost in animal death: about 1/120th of one animal) almost certainly causes less 'death and suffering' than a pound of rice (net cost in animal death: including rodents, insect, reptiles and amphibians, number of deaths may range into the hundreds)." (That's his own "
suffering per kilogram" -- or rather "deaths per pound" -- type of calculation.
) Maybe vegans should start eating venison if it's not too expensive.
As others suggested, I would love to see a table of animals killed per kilogram of different types of food. I'm not aware of anyone working on the issue, but someone really should be! I guess rice was on the list of candidates because of the "green waterfall" of frogs. Any ideas why sugar was suggested as one of the worst offenders? And of course, the severity to animals in the field may depend a lot on where the crop was grown, time of year, harvesting equipment employed, etc.
I never used to eat much rice, but now I think I'll make an effort to steer clear to the extent possible.
Killing wild animals is plausibly a bad thing. For example, here's one simple model of why. Suppose a habitat has a carrying capacity to support a fixed number of frogs. If we kill a frog, then a new one replaces it sooner than if we had let it die naturally later. Suppose frogs have hedonically neutral lives until the point of death, and then death is significantly negative. Then killing a frog sooner means that it's replaced sooner, which means more total deaths per unit time, which is bad. For example, if we consistently kill frogs at half the age whereat they naturally would have croaked (sic), then we double the amount of deaths and, in this model, double the amount of suffering.
However, there were a lot of "ifs" in that previous paragraph. Maybe killing a frog by rice farming -- by disrupting the soil and plants -- prevents its replacement frog from arising until later than the delay for the replacement frog when the previous one died naturally. And how painful is death by harvester compared with death by parasites or death by bird? And are frog lives hedonically neutral, or are they negative, in which case we should kill them sooner?
And how do different plant crops affect the carrying capacity of the habitats themselves? Do pesticides keep down wild-animal populations on the crop lands, such that they support less life than if they were wild? Or does the cultivation of fast-growing and energy-rich food plants allow for more animals than before the land was used for farming?
These seem like daunting questions, but the answers are quite important. I'm sure we could make some good first-pass guesses using a little ecological theory combined with field reports of population densities in various settings. There's a wealth of ecological studies of those sorts of parameters.
While we're at it, there's no reason to limit ourselves to the impacts of food production. What other human operations have big animal impacts? Agriculture probably is near the top of the list, but other candidates include
- Construction: This is probably good in my book because, even though it kills animals in the short term, it prevents habitat for decades/centuries afterward.
- Building roads and paving paradise to put up parking lots: Probably good because many animals are prevented from existing on that land. However, road kill is an unfortunate side-effect; based on Merritt Clifton's statistics quoted in the Wikipedia roadkill article, I would guess each person in the US kills about ~0.5 vertebrates via roadkill per year. (This seems even possibly low, but I used to live in a rural area where I saw roadkill all the time.)
- Climate change (partly due to farming, of course): Most likely bad if it increases wild populations, though I'm not 100% sure of the net impact on wild-animal abundance.
- Clearing forests: Probably good due to reduced animal habitat despite massive short-term suffering and death. Maybe bad if they're temperate forests with small animal populations to be replaced by faster-growing fiber.
With our public face, I think we should avoid overemphasizing harvester-killed frogs and continue to focus on animals in factory farms, because (1) the moral clarity of the latter concern makes it easier for people to latch on, and (2) animals in factory farms is more viscerally compelling. Also (3) until we learn more about the different harvesting impacts of different types of foods, our expectation of those impacts cancels out in either direction, and we're still left with the major harm of factory farming that doesn't cancel out. Moreover, (4) factory farming (unlike venison) almost certainly causes more killed frogs and mice than most plant foods because farm animals needs to eat many times their weight in plant crops during the course of their lives.
Once people have begun to care about animal suffering, though, I think we should begin to raise awareness of harvest massacres, just like we should raise awareness of the more general issue of
wild-animal suffering of all types.
[Edit: Here's one possible downside of venison. If we kill big deer, then maybe it increases the population of smaller animals that can now eat the former deer food. Those smaller animals probably have worse lives and will die sooner, which implies more total suffering. This is just one speculative scenario...]
When I first became vegetarian in 2005 after reading Peter Singer, my sister told me I was crazy because I killed all sorts of animals in numerous other ways (e.g., buying clothes). Rather than becoming discouraged with the whole enterprise and wallowing in apathy, I decided that she was right! I soon became concerned with the suffering of all kinds of animals in nature. I hope at least some fraction of vegans follow this path, for the sake of preventing directed panspermia and lab universes.
by 
