[millettjon]

This completely ignores the fact that grain fed factory cows are a problem but pastured cows actually store carbon in the grass roots and also reduce emissions by not tilling, and using less fossil fuels, fertilizers, and herbicides.

Protein doesn't directly fuel exercise. Most people on paleo type diets target a specific number of grams of protein for muscle maintenance and use carbs or fat to fuel the exercise. So biking more distance would mean eating more rice or potatoes or coconut oil for fuel. So the CO2 impact of the biking calories would be similar to the vegan levels.

[thinkmilitant]

As someone who has been shifting their diet over to vegetarian for environmental reasons, I am interested in this. Can you provide any support for your claim that pasture cattle are less damaging then factory cattle?

I know that pasture raised cattle are not sustainable to feed the masses, but at this point I would just be glad to enjoy a guilt free steak every now and again. ;-)

[dakrootie]

I don't know if this answers your question, but do read The Vegetarian Myth when you get a chance. It is one of the most profound and wonderful books I've ever read about the subject of sustainability/ethics for vegetarianism vs. omivoreism. Lierre Keith, while rather radical, makes a beautiful argument as to why meat (in moderation and humanely raised) is preferable to a veg-only diet. This is one of the top five books that's changed the way I see the world. Cheers!

[millettjon]

http://edis.ifas.ufl.edu/ss574

Also Google Soil Carbon Cowboys.

There used to be many tens of millions of bison living on North American grasslands.