Meat Eaters Guide: Methodology - Environmental Working Group

Meat Eaters Guide: Methodology
For each meat protein, we provide the results of the LCA GHG calculations for each system based on
the available input data. Due to the limitations of the initial scope of work, we are only able to provide
detailed breakdowns of emission sources for four of the modeled production systems: beef, poultry,
cheese and lentils, as well as for the three primary feed inputs: corn, soy and alfalfa. We also provide
details for the post-production emissions for all meat proteins.
Allocation Factor: Since the functional unit in this analysis is 1 kg of consumed, edible product, as
opposed to live carcass weight, our model applies mass-based economic allocation to derive a multiplier
used to estimate the GHGs associated with the edible meat. This accounts for the fact that the entire
animal is not eaten. The multiplier is based on the actual fraction of an animal’s live weight that is available
for consumption (55 percent, in the case of beef) and the relative economic value that is allocated
to the edible product (87.2 percent in the case of beef). 45 The multiplier is then multiplied by the emissions
for 1 kg of live weight in order to calculate the emissions for 1 kg of edible meat. For meats such
as lamb, for which a relatively low fraction of overall carcass is edible, the multiplier will be higher than
for other meats.
Table 3. LCA Allocation Factors
Meat Product
22
Edible fraction
of live weight
Relative economic
value of edible
fraction
Multiplier for
mass-weighted
economic
allocation*
Environmental Working Group Meat Eaters Guide: Methodology 2011
Sources
Chicken 0.56 0.95 1.70 Pelletier (2008) Pelletier
(2006)
Turkey 0.40 0.95 2.38 Fuller
Pelletier
(2006)
Pork 0.65 0.89 1.37 Wirsenius
Beef 0.55 0.84 1.53 A. Barber, et al
Lamb 0.42 0.87 2.08 A. Barber, et al
Oily Fish 0.50 0.91 1.82 LCA Food Database
White Fish 0.45 0.91 2.02 LCA Food Database
*(Multiply emissions for 1 kg of live weight by this number to calculate emissions for 1 kg of edible meat.)
With the exception of seafood produced overseas, the post-farmgate CO 2 e emissions per kg of consumed
product are based on domestic production with an average transport distance of 2,414 Km
(1,500 miles) for the end consumer product (2,253 Km in semi-trailer truck (1,400 miles) and 161 Km
(100 miles) in single-unit truck). 46 Data results are available upon request for emissions based on local
and imported/shipped food products. Cooking assumptions for all products are provided in Annex B.