High and mighty claims of superiority are often annoying. There are great reasons to be vegan/vegetarian, but phrases “eco-friendly” and “earth-based” are really good at pissing me off. It’s not always easy or cheap to be a healthy vegetarian. It’s also often not much more environmentally friendly. This is not any more true for vegans than vegetarians, I believe, dairy is actually a higher carbon food than meat. Home-raised chicken eggs/meat is another story…
The article in our school newspaper that got me started: http://www.collegian.com/index.php/article/2010/10/101910_vegan
Here’s a few quick quotes: “It’s great for us to see colleges really making an effort to make earth-based diets more mainstream.”
“…a lot of students choose veganism because it promotes the humane treatment of animals, and is more eco-friendly.”
My research relates to grass-based livestock production. We study how different management techniques (and forest-grassland conversion) impact soil organic matter levels. Research is by no means clear on the carbon intensity of grass-based livestock products, but I don’t think it has to be.
Humans have evolved eating a variety of foods. People in many parts of the world have very meat-based diets. Other regions, products of land-cultivation generally were available alongside meat and dairy products. Grass-based farming is an important part of traditional agricultural systems. Grasslands build soil organic matter. They are more effective at building organic matter with moderate levels of grazing. (See, Conant, Ecological Applications, 2001: GRASSLAND MANAGEMENT AND CONVERSION INTO GRASSLAND: EFFECTS ON SOIL CARBON) This organic matter is a store of nutrients that is available to future crops years down the road when that grassland is converted into cropland. Traditional fallow/grazing/tilled rotations would usually last 10 years or more, but at least 3 years seem necessary to build any statistically significant amounts of carbon (the largest & easiest to measure component of soil organic matter).
Generally, grasses do not absolutely require animals to stay alive. Animals however, concentrate and redistribute nutrients in plant available forms. This helps plant productivity. Additionally, many crops cannot grow in places that are hilly (yes there are examples in the pacific islands, but these high intensity systems require huge amounts of man-power (sometimes called cultural energy)). Animals however can easily harvest energy by grazing grasses that grow in these areas (recall images of Alpine grassslands of the Austrian Alps, are there cows in this image?.)
I believe these are substantial reasons that animal products can be an important part of a sustainable food system. Obviously I have not talked about feedlot animal production, because there are not many good arguments that feedlot production can be part of an environmentally sustainable food system. Here I am simply addressing hardline arguments that meat/dairy are an unsustainable option, that is without question environmentally worse than veganism.
I have not discussed issues of fertilizers and nutrient pollution here, that’s probably a much bigger topic. Quickly though, I will note that grassland systems can absorb a lot of nutrients from grazers, preventing runoff downstream. The images of cattle standing in rivers pooping is another story where all that we need is some fencing, a minor challenge to sustainability compared to the other challenges we face as a society.