Meat Eaters Guide: Methodology - Environmental Working Group

By: Kari Hamerschlag, EWG Senior Analyst
Kumar Venkat, President & Chief Technologist, CleanMetrics Corp.
Introduction
Environmental Working Group (EWG) partnered with CleanMetrics Corp., a Portland, Ore.-based environmental
analysis and consulting firm, to carry out “cradle to grave” life cycle assessments (LCAs)
of greenhouse gas (GHG) emissions for selected protein-rich foods, from production of animal feed to
the food waste thrown in the trash.
The LCAs calculate GHG emissions from each major process, from the production and application of
fertilizers, pesticides and other materials used to grow crops through to the processing, transportation
and disposal of unused food at the retail, institutional and household level. 1 The LCA also accounts
for waste from the portion of the animal carcass that is not available for consumption.
This document provides a detailed report on the methodology, assumptions and results of the
lifecycle assessments of 20 plant and animal foods commonly consumed in the United States. Due
to lack of data, the analysis focused on typical, conventional food production systems rather than
organic production systems or those based on best management agricultural practices that might
result in lower emissions. While our LCAs focus exclusively on GHG emissions, climate impact is
just one of many critical environmental and health factors to consider in evaluating protein choices.
The Meat Eater’s Guide to Climate Change and Health provides a broad overview of the health and
environmental concerns linked to animal production.
Section 1 addresses the boundaries (key elements included and excluded) of the LCA, the main
production inputs and emission outputs, sources of data and the assumptions related to each of the
main stages of production and consumption. We also provide a detailed explanation of the validation
process, including a chart comparing our findings to other comparable and mostly peer-reviewed or
government-sponsored LCA studies of that product. We describe many of the underlying uncertainties
and variability associated with estimating GHG emissions from food production and provide concrete
examples of how emissions can be reduced by better management practices. Section 2 describes the
essential production, consumption and modeling details and emissions of each production system as
well as the results of the GHG calculations for each based on the available input data.
A. LCA Boundaries and Functional Unit
The functional unit used to calculate GHG emissions 2 is 1 kilogram of consumed, edible product. This
differs considerably from the current set of published LCAs, which typically calculate only the GHGs
associated with the production of one unit of edible meat or live carcass. Our model goes further to
consider the GHG’s associated with material and energy expended or produced at each major stage
Environmental Working Group Meat Eaters Guide: Methodology 2011 5