Meat Eaters Guide: Methodology - Environmental Working Group

UK government by the UK’s national standards body, the British Standards Institution (BSI Group).
B. Apportionment of GHGs to food versus non-food products (co-product
allocation)
Some foods considered in this analysis are derived from animals or crops also used to make nonfood
products. For example, animals are used to produce meat, leather, and cosmetic ingredients,
among other items. GHG emissions presented here consider only the fraction of emissions associated
with food production.
CleanMetrics accomplishes this allocation by apportioning GHGs from animal or crop production to
food and non-food products based on – in order of preference – the relative economic value (weighted
by mass) or a relative biophysical factor such as mass, energy or nutrition content associated with
each type of finished product. This is called “co-product allocation.”
In practice, mass-weighted economic value has proved to be the most reliable basis for allocation,
particularly when final products are highly dissimilar or in cases where one or most of the final products
are materials or energy other than food. 6 CleanMetrics used this method for each of the food
items considered in this analysis. See Table 3 for the specific allocation factors used in the calculations.
Recycled materials are both produced from and used in animal- and crop-based food production.
These GHG calculations model the emissions from recycling facilities and recycled materials used
to grow, process, package or transport the food (e.g., recycled food packaging) using the “recycled
content” method. 7 For any particular food, GHG estimates include emissions from delivering waste
material to a recycling facility.
C. Modeling Agricultural Processes: Data and Emissions Factors
1. Key Inputs and Emission Outputs
CleanMetrics modeled the GHG emissions of a number of typical, conventional (as opposed to organic
and/or best management) production methods for each of the foods in the Meat Eaters Guide
based on a detailed inventory of inputs and outputs and associated emissions. The table below gives
a sense of some, but not all, of the sources of GHG emissions considered in the LCAs.
Environmental Working Group Meat Eaters Guide: Methodology 2011 7