The ugly:
Pound for pound, beef production demands at least ten times as much water as wheat production, and, calorie for calorie, it demands almost twenty times as much energy. Livestock are major sources of greenhouse-gas emissions, not just because of the fuel it takes to raise them but also because they do things like belch out methane and produce lots of shit, which in turn produces lots of nitrous oxide. One analysis, published in the American Journal of Clinical Nutrition, concluded that, in terms of emissions, eating a pound of beef is the equivalent of driving forty-five miles. (Grass-fed beef—recommended by many primal enthusiasts—may produce lower emissions than corn-fed, but the evidence on this is shaky.)
http://www.newyorker.com/magazine/2014/07/28/stone-soup
Not untrue, just irrelevant. If you grow beef from corn grown from oil produced ammonium nitrate, it's certainly not going to help reduce emissions, if you are into that sort of thing. So let's stop doing that, shall we?
I love her summary of this event:
Agriculture was “invented” several times, in different parts of the world, by people making use of the plants they found growing wild around them. The first time was probably about ten thousand years ago, in southeastern Turkey, when early farmers began cultivating einkorn wheat. The crop was a big hit, and, at least by the standards of the day, it spread rapidly. (This is sometimes referred to as the Big Agricultural Bang.) Wheat was being sown in Greece around eight thousand years ago, in the Balkans and in Italy seven thousand years ago, and in India and Scandinavia five thousand years ago. Meanwhile, around nine thousand years ago, a group of proto-farmers in southwestern Mexico began cultivating maize. It, too, quickly caught on, and was being grown in Panama seven thousand years ago and in Colombia six thousand years ago. Also sometime around nine thousand years ago, rice was domesticated in the Yangtze Valley.
This is also good:
“The adoption of agriculture, supposedly our most decisive step toward a better life, was in many ways a catastrophe from which we have never recovered” is Jared Diamond’s dour assessment, offered in an essay titled “The Worst Mistake in the History of the Human Race.”
Like Stone Age hunter-gatherers, early farmers left little behind—just some burnt grain, mud foundations, and their own bones. But that’s enough to reveal how punishing the transition to agriculture was. According to a study of human remains from China and Japan, the height of the average person declined by more than three inches during the millennia in which rice cultivation intensified. According to another study, of bones from Mesoamerica, women’s heights dropped by three inches and men’s by two inches as farming spread. A recent survey of more than twenty studies on this subject, published in the journal Economics and Human Biology, found that the adoption of agriculture “was observed to decrease stature in populations from across the entire globe,” including in Europe, the Middle East, Asia, and South America.
Early farmers were not just shorter than hunter-gatherers; they were also more sickly. They had worse teeth—one analysis from the Near East suggests that the incidence of cavities jumped sixfold as people started relying on grain—and they suffered from increased rates of anemia and infectious disease. Many now familiar infections—measles, for instance—require high population densities to persist; thus, it wasn’t until people established towns and cities that such “crowd epidemic diseases” could flourish. And, by living in close proximity to their equally crowded farm animals, early agriculturalists helped to bring into being a whole set of diseases that jumped from livestock to people.
“The adoption of agriculture,” Diamond notes in his most recent book, “The World Until Yesterday,” provided “ideal conditions for the rapid transmission of microbes.” According to Daniel E. Lieberman, a professor of evolutionary biology at Harvard and the author of “The Story of the Human Body,” “farming ushered in an era of epidemics, including tuberculosis, leprosy, syphilis, plague, smallpox and influenza.”
It took thousands of years for human bodies to recover; Lieberman reports that “it wasn’t until the twentieth century that Europeans were the same height as cavemen.” And, almost as soon as the stature gap closed, new problems arose. People began to grow not just taller but also wider. During the past several decades, rates of obesity, hypertension, fatty-liver disease, and Type 2 diabetes have soared.
For millions of years bison and other grazing animal ran around and helped grasses build top soil. That's the way our ecology worked, as elegantly summarized in "the Vegetarian Myth". I doubt we could recreate that, but if restoring natural processes that sequester carbon in soil is your goal, that's the way ahead.