Greenhouse gas emissions from pig and chicken supply chains – A global life cycle

Greenhouse gas
emissions from
pig and chicken
supply chains
A global life cycle assessment


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Food and Agriculture Organization of the United Nations
Rome 2013


The livestock sector is one of the fastest growing subsectors of the agricultural economy, and faces several unprecedented and concomitant challenges. The sector needs to respond to the increasing demands for livestock products that are arising from population growth and changing consumer preferences. It also has to adapt to changes in the economic and policy contexts, and in the natural environment upon which production depends. At the same time, it has to improve its environmental performance and mitigate its impact on climate. The pig sector is the biggest contributor to global meat production, with 37 percent in 2010. Chicken meat accounts for about 24 percent. Global demand for pig meat, chicken meat and chicken eggs are forecast to grow by 32 percent, 61 percent and 39 percent respectively during the period 2005-2030. If the greenhouse gases (GHG) emissions intensities (emission intensity; or the kg of GHG per kg of product) of these commodities are not reduced, the increases in production required to meet demand will lead to proportionate increases in GHG emissions. Improving our understanding of where and why emissions arise in livestock supply chains is an important step towards identifying ways to improve efficiency and reduce emissions intensity. This report presents a life cycle assessment (LCA) of the GHG emissions arising from pig and chicken supply chains. It provides a detailed analysis of emissions according to region, sector and systems of production. In addition to informing efforts to reduce GHG emissions, it is hoped that the assessment will also help inform public debate on this important subject.

Table of Contents

Definitions of commonly used terms
Executive summary

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1. Introduction

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1.1 Background
1.2 Scope of this report
1.3 The Global Livestock Environmental Assessment Model
1.4 Outline of this report

2. Overview of the global monogastric sector


3. Methods

3.1 Choice of Life Cycle Assessment (LCA)
3.2 General principles of LCA
3.3 The use of LCA in this assessment
3.4 Overview of calculation method
3.5 Data sources and management
3.6 Allocation of emissions between products, by-products and services
3.7 Production system typology

4. Results for pig supply chains

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4.1 Global production and emissions
4.2 Emissions intensity
4.3 Analysis of uncertainty in pig emission intensity
4.4 Comparison of the pig results with other studies

5. Results for chicken supply chains

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5.1 Global production and emissions
5.2 Emissions intensity
5.3 Analysis of uncertainty for chickens
5.4 Comparison of the chicken results with other studies

6. Summary of production and emission intensities


6.1 Commercial systems (layers, broilers, industrial and intermediate pigs)
6.2 Backyard systems
6.3 Gaps in emission intensity within systems and regions

7. Conclusions




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Overview of the Global Livestock Environmental Assessment Model (GLEAM)


Data and data sources


Changes in carbon stocks related to land use and land-use change

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Postfarm emissions


Emissions related to energy use


Alloca tion to slaughter BY-products



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1. Pig population density – backyard
2. Pig population density – intermediate
3. Pig population density – industrial

4. Chicken population density – backyard
5. Chicken population density – broilers
6. Chicken population density – layers
7. Manure methane conversion factor for industrial pigs

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8. Manure methane conversion factor for laying hens
9. Average proportion of N intake retained in live weight by pigs (average for all pigs in a cell)
10. Average proportion of N intake retained in live weight and eggs by chickens (average for all chickens in a cell)

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Country list

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