It probably isn’t what most people would think of when they consider the global changes made by mankind, but the amount of livestock we keep is a big burden on the environment. Approximately 20% of all animals alive are densely farmed, significantly reducing the amount of land available for unfarmed animals. And farm animals are big offenders in producing CO2, and worse greenhouse gasses including methane and nitrous oxide.
To put it in perspective, a fifth of global emissions are farming induced – which is more than automobiles. Changing from a gas guzzling four-by-four to an energy efficient prius saves less emissions than becoming vegetarian. It takes 10 times as much land to feed a person meat as the same calorie value in vegetables – and a lot of that difference is converted into global warming nasties.
I don’t think this counts as a reason to be a vegetarian, however. This is not a matter of absolutes. Simply cutting down on the amount of meat eaten could have a big impact on the environment. Only in the last 50 years did we get meat every day – pre-industrial farmers couldn’t afford it, and hunter-gatherers had to make do with whatever they could get. We don’t need meat often to get benefits from it – and vegetarian food can be just as tasty if you know how to cook it.
But imagine the wildlife parks we could have if we could reclaim nine tenths of all pasture land! If we could give even a fraction of that back to nature, wild populations could recover, rain forests wouldn’t need to be cut down, and global warming would be significantly reduced. Good, no?
This is a good reason to eat less meat, but there are other reasons to eat none at all. See my post about the morality of vegetarianism for why I am a vegetarian.