Good point GB,
the carbon cycle works fine and neutral as long as things stay in the CO2 to plant to food/fuel cycle. Which is why my fireplace is good. I grow trees out back, cut them down for firewood, and then grow some more. I cant keep up!! the trees are winning!!
But skewing the food chain to cattle, pigs chickens and sheep will also skew waste by product emissions to the more potent GHG, methane. tipping the atmospheric thermal balance. which is what the world is doing by going to meat rich diets.
True, we are not designed to be true ruminants for our sole source of digestion, but we do carry a wide range of bacteria including anerobic Methanogens and can and do produce some methane too.
http://www.microbeworld.org/news/art...ogy_farts.aspx
While the amount is not as significant as our domesticated ruminant animals, I was pointing out the cummulative effect of large numbers on seemingly insignificant things we do. I bet everyone knows somebody who has played with matches.