Meat Eaters Guide: Methodology - Environmental Working Group

a kg of lamb. Processing (including freezing and packaging) accounts for 4 percent of total emissions,
followed by home cooking (3 percent), and both waste disposal and domestic transport (less than 1
percent each).
3. Pork Production
The CleanMetrics LCA analysis modeled four typical single-stage pork production systems: two from
Michigan (average- and high-productivity) and two from the country’s leading pork-producing state,
Iowa. In once case, the animals have some pasture access, but the feed rations are similar in both
confined and some pasture access.
a. Key Production and Modeling Details
• One-stage system with sows and piglets raised together 52
• A pork system with pasture access uses nearly the same feed inputs (mostly corn, soybean
meal and other grains) as a confined system, since the animals do not obtain much nutrition
from grazing on pasture.
• Manure management system is assumed to be liquid slurry with natural crust cover. Although
some manure was deposited on pasture in the Iowa pasture system, the model does not
separate that out due to lack of data.
• Fuel and electricity are main energy inputs for farm operation. (Energy used for delivering
water is excluded due to lack of data).
• Hogs in each system are sold to slaughter at a weight of around 260 lbs
• Transport assumptions are similar to beef and lamb systems.
b. LCA Results
Table 8. Greenhouse Gas Emissions from Pork Production (at farmgate)
Pork Production System kg of CO 2 e per pound of edible pork
Michigan (average productivity)
4.17
Iowa (confined) 4.52
Iowa (some pasture) 5.17
Average 4.62
Environmental Working Group Meat Eaters Guide: Methodology 2011 29