Meat Eaters Guide: Methodology - Environmental Working Group

Meat Eaters Guide: Methodology
as crops, animals, soil, etc.) within a bounded geographical area and specified time frame that takes
external inputs (such as fertilizers, water, energy, etc.) and produces useful outputs (such as grains,
vegetables, meat, etc.) using specific production methods. Due to limited available data, only one production
method was considered for a few items, including chicken, peanut butter, lentils and orchard
grass.
We selected specific conventional production systems to model based primarily on a) the availability
of input data, and b) how representative it is of the industry as a whole.
We made a concerted effort to find publicly available production data from leading production regions
for major meat categories. These public data sources are typically university agricultural extension
programs, university agro-economics departments and state- or province-level departments of agriculture.
These sources often provide data in the form of cost and return studies or budgets that include
all the specific inputs consumed by a typical production system and outputs generated by the
system in a specified region. We judged the quality of the data based on a number of criteria, including
completeness and consistency with other data sources. We rejected some data sources that did
not meet these standards (in some cases, after running a trial analysis to further evaluate the data
quality).
Data was not always available for states that produce the most of some types of meat. Generally,
however, we were able to find good production data from one of the top three production states for
major categories such as beef and pork, as well as for dairy and eggs. We supplemented these primary
sources with data from other regions. The two poultry meats, chicken and turkey, are the exception
to this. The broiler chicken production data is from a large-scale confined feeding operation in
British Columbia, Canada 11 and the turkey calculations are based on data from Pennsylvania.
The data models in this analysis were based on typical production systems, rather than best-management
agricultural practices that might result in lower emissions. Because of differences in inputs,
management practices and consumption patterns, there is some variability in the exact GHG emission
results for a given product. In Section 4c, we discuss how emissions might change with better
management practices.
3. Data Sources for Calculating Emissions from Each Stage of Production
Using basic emission factors, equations and calculations from the Intergovernmental Panel on Climate
Change (IPCC), the U.S. Environmental Protection Agency (EPA) and other recognized sources
described below, CleanMetrics analyzed each aspect of the input data to calculate the GHGs associated
with each activity along the supply chain.
The analysis used emission factors and calculations for the extraction and combustion of primary
fuels – as well as non-energy-related factors for GHG emissions inherent in industrial, agricultural,
transport and other processes – generated primarily from the following two sources:
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Environmental Working Group Meat Eaters Guide: Methodology 2011