Saturday, March 5, 2011
The Till-Kill Argument
Yesterday my animal rights class discussed the "Till-Kill Argument"--an argument due to animal scientist Steven Davis (made famous when Michael Pollan appealed to it in this NYT article). The argument is that if we want to do the least harm to animals, we're better off with a "veg & beef" diet than a vegan diet. Here's his math:
120 million ha is the total amount of cropland in the US. That's about 19% of US land (another 25% is animal pasture). Suppose (just suppose) that all that land were used to grow an all-plant human diet. There would still be many animals killed, because of "till kill." That's like road kill, except the animals--voles, rabbits, mice, ground birds and the like--are killed by farm machinery. Davis estimates a death toll of 15 per ha.
Now suppose half that land is used for plant farming, and the other half for pasturing beef cattle. The more tilling required for a crop, the more animals killed. Cattle farmers plant low-till forage (Davis says), so there are fewer passes over the land. That means, he says, a death toll of just 7.5 per ha.
Of course, you've got to kill the cattle too. He assumes 60 million ha worth of plant food is equivalent to 74 million cattle worth of beef--double the number of beef cattle now killed yearly in the US.
Bottom line: fewer animals killed in the "veg & beef" scenario. QED.
Note: he's not saying this would be the case no matter what animal species is eaten. If chickens rather than cattle are "grown," and we double the number of chickens currently eaten in the US every year, that would be 16 billion chickens. The death toll of the vegan scenario is way lower than that. This is a beef-specific argument. If we want to minimize killing, "veg and beef" is the way to go...says Davis
What should be said about this argument? Here's how a debate might go:
Pro-vegan: The killing in the vegan scenario is all accidental. It's foreseen, but not intended. In the veg & beef scenario, the killing is intentional, so worse. And don't think that's a merely scholastic distinction. We all think people who deliberately kill squirrels in their backyards are doing something worse than people who accidentally run over them in their cars.
Pro-omnivore: Even if that's so (and it's debatable), there are trade-offs. If one intentional killing would prevent a billion accidental killings, we'd all think it was a "necessary evil." 74 million intentional cattle-killings are worth it to prevent a half billion accidental till-kills.
Pro-vegan: These numbers are implausible. Plant farming till-kill may now be lower than 15 per ha, since new genetically engineered crops are low-till, compared to traditional crops. Plus, the argument doesn't take into account other ways that livestock crowd out wildlife, because they compete with them for resources, destroy river banks, interfere with migration (because of fencing), and so on. There's more death on the beef side than Davis allows.
Pro-omnivore: The point is that vegans just assume that plant farming doesn't kill animals. But it does--a lot! At the very least, it's an open question what kind of agriculture kills the fewest animals.
What next? Are there better, stronger arguments available on one side or the other? My class will continue discussing the article on Monday, so it would be great to have some input from the smart people who comment at this blog!