How environmentally responsible/green and sustainable is the paleo diet?
A common criticism of eating beef is that it's not sustainable. Specific arguments include:
By some estimates, 2500 gallons of water are needed to produce a single pound of beef.
The amount of methane produced by cows is a large contributing factor in the production of CO2 in our atmosphere, thus contributing to global warming. Plus, some of this methane seeps into groundwater, which poisons the earth.
The massive demand for beef promotes slash-and-burn of rain-forests.
Raising cows is a direct cause of desertification.
I consider the last two arguments the weakest, because ethically-raised pastured cows have been shown to reverse desertification, and the destruction of rain-forests in order to create feedlots is an unethical practice that is counter to grassfed beef production anyway. If you have further counter-arguments, please mention them, but I'd like to focus on the first two points.
Since the estimates for water use required to produce beef varies considerably (http://bit.ly/e6FE54), do we know what factors are involved in this computation? Is it based on water an animal needs to drink in its lifetime before it's butchered, or is it in great part based on the need to irrigate corn crops? In other words, has anyone shown that grassfed beef requires substantially less water than conventional beef? How can we argue that this may be the case?
Second, some argue that cow production of methane may pollute as much as a car, daily. (http://bit.ly/hVAIgC) However, this is in great part due to what we're feeding cows; natural pasture does not result in the same amount of methane production, whereas ryegrass and other chemically-fertilized pasture is not as nutritious, and results in increased methane production. Does anyone know how substantial this difference is, and can we realistically argue that cows raised on natural pasture are not large contributing factors in methane production and ammonia seepage in the ground?
It seems to me that many of the arguments about beef not being sustainable is in regards to conventional cow rearing, and not necessarily applicable to grassfed cows (never mind the fact that the human population is arguably not sustainable regardless of diet). It would be nice to have information backing up this claim, however.