I realize this first paragraph is a question of ethics, however the sustainability side of this issue is certainly scientifically relevant. Also, many of the ethical arguments against our meat industry depend upon claims that may have a basis in scientific literature (like the notion that animals feel pain, or that they are consciously aware of their situation), which some people may wish to dispute.
I agree with most of what Peter Singer has to say on this topic. It would be odd to dispute that all cattle and poultry feel pain (although I'm happy to flesh this one out). It also cannot be denied that animals are mistreated and experience a great deal of pain and suffering throughout the production life-cycle of meat. It seems unreasonable that we should impose prolonged pain and suffering on a large number of animals merely for personal enjoyment. The consequences just don't seem fair. I get the temporary sensation of enjoyment from the taste, while some animal endures a life-time of physical and psychological pain, just to die.
On the sustainability side of the issue, I would argue that a vegetarian diet is far more sustainable than a predominantly meat diet. It takes roughly between 6 and 10 lbs of grain to produce around 1lb of meat. It varies a little but the conclusion is the same; we are reducing the amount of potential end product in order to sustain a luxury. As the global population increases and the demand for meat inevitably goes up, the meat industry grows. This means the clearing of more and more land to grow grain that is essentially reduced to meat, and more and more land cleared for factories a paddocks. Not only is it wasteful but it has a significant impact on the environment and it is by no means sustainable.
The meat industry also plays a large role in carbon emissions. Cattle emit methane which has a Global Warming Potential (GWP) of 21; it is a more potent a greenhouse gas than carbon dioxide. In-fact, methane emissions from the meat industry may have a greater impact on climate change than the coal industry, since, as Singer argues, the coal industry emits particulates (soot and such) which have a cooling effect on the atmosphere. This cancels out some proportion of the positive radiative forcing from carbon. The release of methane from the meat industry, however, does not have this buffer.
Moreover, when you start taking in to account transportation of both grain and meat, in order to produce the end product that we get in our supermarket, it becomes quite clear that we ought to at least scale down the meat industry, if only to reduce carbon emissions.
In the end, vegetables are far cheaper to produce and we can get all of the same nutritional value from a wholly vegetarian diet. Vegetarian diets are far more sustainable since we could use much of the grain that is fed to non-humans as an end product for our own diets. This is not merely a more ethical way to live, but it's a far more economical way to live, and to top it off we would reduce the impact on our environment by a huge amount!
Does anyone share my perspective? Are there any facts you would like to add or dispute?
Edited by seculardave, 03 August 2012 - 09:35 AM.