Contributions to Global Climate Change: A Cross-­National Analysis of Greenhouse Gas Emissions from Meat Production

Abstract

will be least affected by climate change or that have the most resources available to adapt to it, or both (see chapter 1). This chapter considers the total GHG emissions and emissions intensities of beef, pork, and chicken production across countries and over time. What factors drive total emissions and emissions intensities? What is the relationship between total emissions and emissions intensities? Geographically , where are the most emissions coming from and where is the most GHG-efficient meat production? Does more intensive meat production produce fewer GHG emissions? GHG efficiency is one of several kinds of efficiency that should be considered when assessing the sustainability of meat production, but GHG efficiency has the greatest direct implications for global climate change. Animal Agriculture and GHG Emissions The main types of GHG emissions from animals are methane (CH4), which has a global warming potential (GWP) that is twenty-five times that of CO2, and nitrous oxide (N2O), which has a GWP that is nearly three hundred times that of CO2. These emissions are the result of enteric fermentation (i.e., a key process of ruminant 1 digestion) and from manure, which is either collected in pits or lagoons (e.g., "manure management systems"), left to decompose on a pasture, or applied to soils as a fertilizer. Animal diet (and more technical chemical manipulation of the diet) can influence emissions from enteric fermentation, with greater roughage/less nutrient-dense foods in the diet generating more GHG emissions than diets with higher amounts of concentrated feed (Macleod et al. 2013, xix). The emissions from manure management practices vary depending on their specifics and the temperature of the location, as do the emissions from manure left on pasture and applied to soils. Worldwide, total GHG emissions from cattle, pigs, and chickens combined increased by 66 percent from 1961 to 2015. However, this increase in emissions has not been even across the globe. Emissions over the past fifteen years have increased the most in South America and Africa, and South America has been the top-emitting continent since 2001 when its emissions surpassed those of Asia. In 2015, the top three continents for total meat animal emissions were South America (558,000 gigagrams [Gg] Downloaded from http://direct.mit.edu/books/book/chapter-pdf/270475/9780262355384_cbx.pdf by UNIVERSITEIT TWENTE user on 22 October 2021