In the comments for the question Is being a vegan more environmentally friendly than otherwise Flimzy said:
I think it is easier to have an environmentally-friendly diet if you're a vegan, but there are environmentally friendly ways of consuming meat, too. They're just harder to do. If you raise your own free-range chickens or beef (or buy from someone locally who does), it's pretty environmentally friendly, for instance. But this is much harder than having your own local veggie garden, or buying veggies from a local farmer's market.
I also suspect that these numbers are only taking into account "traditional production" means. A graph showing free-range (or other alternative methods) and local poultry, beef, pork, and dairy, would be very interesting as well.
Oddthinking makes a good counterpoint:
You are making some claims there! How about some evidence? My first impression is that free-range is less environmentally-friendly, as more land must be cleared. Morally right is a separate question. And then there is the question of how much land is dedicated to feeding the animals.
My gut feeling tends to agree with Oddthinking, The UN reports "Global meat production is projected to more than double from 229 million tonnes in 1999/2001 to 465 million tonnes in 2050", as more people are becoming more prosperous, their meat consumption increases. These methods would have to scale to fit the increased demand for more meat.
John C weighs in:
"antibiotics and hormones, chemicals from tanneries, fertilizers and the pesticides used to spray feed crops." Personally, I consider that more an indictment of the industrial livestock industry - cattle that are grass-fed, and not given rBGH and antibiotics, would have none of those problems.
So it seems to be a common belief that there are alternative methods of meat production (possibly free-range meat) that are better than the environment than factory farming. So what is the evidence that free-range, or other alternative methods of meat production actually are better than industrial, factory farmed methods?
I have heard there is some research going on to grow meat in a lab but this method isn't here yet, but it looks very promising from both an environmental as well as ethical prospective.