According to a compilation of sources on The Sharpener, the average American diet produces 1.5 tonnes more carbon per annum more than a vegetarian diet. When you compare that to the average British citizen’s carbon footprint of 5 tonnes per annum (11 tonnes including industry, according to The Guardian, that’s quite a lot.
Non-ruminant species (especially pigs, poultry, rabbits) and unconventional animals (eg: guinea pigs) should be promoted (using local feed resources) as meat producers while meat production from ruminants should have a lower priority.
A document on Virtual Centre explains:
Methane […] Although non-ruminant animals do produce methane from enteric fermentation in their large intestines, the production is small compared with that which occurs in the rumen of ruminant animals.
The National Atmospheric Emissions Inventory has information on a few examples:
- Poultry produce 0 kg of enteric methane per head per year
- Pigs, 1.5 kg
- Sheep, 3.2 - 8 kg
- Cattle, 116 kg
So, the checklist for buying food becomes looking for foodstuffs that are:
*locally produced (better for the local economy and the food-miles issue),
*organic (though less yield and hence more carbon than non-organic farming, it does not pollute the surrounding ecosystem),
*free-range (I’ve not seen a single pleasant image of a battery farm),
*high-yield for acreage biomass pyramid,
*low-greenhouse-gas-emitting (plants over poultry over pigs over cow).
The Guardian also has an overview to the issue and with some comment.