I haven't taken the time to watch the Cowspiracy movie but instead read the facts behind the movie on the Cowspiracy.com website. I find reading is the quicker than watching talking heads to get info into my head. Many of the numbers of methane and water use by animal agriculture I have seen before. They are probably true. It is the interpretation of the impacts that I believe are over estimated. They are calculating the impact as if none of the water would be used or methane released to the air if humans were not raising animals. When calculating climate change caused by methane and CO2 you have look what actually changes...
When using fossil fuels, humans take carbon that has been stored for millions of years and release it into the atmosphere. So you could argue that 100% that is burned contributes to climate change.
With animal agriculture we change who is the top predator in the food chain. If we weren't eating beef off of the plains there would be buffalo eaten by wolves. If we were not growing grain on the plains there would be grass growing there with animals eating it and being eaten by predators. So the cycle of CO2 and methane wouldn't be much different. What does change is when we till ground or cut forests is the possible loss of CO2 stored in the soil. So agriculture practices that cause the movement of Co2 from the soil to the atmosphere adds to global climate change. Draining peat swamps for palm oil plantations or pasture allows the peats carbon to oxidize and go into the air. Tillage practices for crops may lessen the percentage of carbon stored in the biomass in the soil. This goes for tillage for crops for humans or animals. Farming practices that conserve or increase the carbon content of the soil have a neutral or positive impact on CO2 in the atmosphere. Perennial pastures or no till crops may be net sinks of carbon. So agriculture can have a role in combating global warming.
The CO2 from additional cropland that loses carbon from the soil should be calculated as the impact of animal agriculture toward global climate change. Past animal raising was a way to utilize plants that humans couldn't eat directly. So waste food, parts of plants we didn't eat and perrenial pasture was fed to animals. Animals were part of the carbon and nitrogen cycle on mixed use farms. My own family had a dairy farm where a 7 year cycle of grass pastures was followed by 2 years of tilled grain crop and then reseeded to grass and clover. So the carbon stayed about the same, accumulating over 7 years of pasture and then some lost when tilled for crops. The manure was spread on the fields to recycle.
Animal raising on feedlots breaks the cycle of manure returning to the cropland. Some is sold as steer manure and put on gardens elsewhere. Some is over concentrated and is leaching into the water.
Farming has huge ecological impacts from coopting plant resources from wildlife to human consumption. Animal agriculture increases the amount of land dedicated to human use. Farming uses huge amounts of fossil fuel. Over consumption of meat products contribute to health problems. So there are many reasons to cut the amount of meat we eat.
There are many agriculture practices that could be changed to cut the unwanted ecological impacts.
But I don't think we can attribute all the methane from animal agriculture as having more impact than fossil fuels on global climate change. And water use that falls as rain is different than water that is pumped from elsewhere when calculating water use changes from agriculture. I believe it is wise to look at actual impacts to decide the best actions to advocate for in the future.
I did watch the video and agree with you on most points. The video pushes the conclusion that a vegan diet is necessary for a sustainable earth, but in doing so, stretches its numbers a tad. The numbers are all there, but when calculating land areas necessary, it always considers meat consumption at the insane level Americans currently pursue. Buried in the video is a statement that if meat consumption went from large portions each meal to ounces per week, all works out. Also buried in the video is your point that grazing animals are necessary for conditioning land in sustainable agriculture. The push toward a vegan diet is the weak point of the movie: it puts a moral impetus which stretches the facts. Also, because the film maker is a city boy, he explores the supply and consumption differences between city and rural which we talked about last night as the spacing between castles, but does not fully understand the rural side.
Humans have been killing animals and eating meat all through their history so as an unenlightened historian, I cannot agree with the video's seemingly "moral" conclusion. I do think that the raising of cattle and other browsing animals should correspond to the conditioning of land for sustainable agriculture and that our diets should reflect the decrease in meat and dairy consumption this implies. The earth cannot sustain its human population on a hunter-gatherer meat quantity diet and far less so on the current meat with every meal agribusiness maximized profit, earth be damned, model.
Peace and ounces of meat per week from Peace Lane,
Hope, love and peace will bring prosperity.