Last week, the United Nations announced the selection of Frank Mitloehner, PhD, to chair a committee within the U.N.’s Food and Agricultural Organization (FAO) to measure and assess the environmental impacts of the livestock industry. This is a positive development as Mitloehner, an air-quality specialist at the University of California-Davis, will bring objective, scientific leadership to an organization that has shown some anti-livestock bias in the past.
The story begins in 2006, with the release of the FAO report titled “Livestock’s Long Shadow.” That report’s authors infamously claimed the livestock sector is responsible for 18 percent of global greenhouse-gas (GHG) emissions, a greater share than all transportation combined. That figure continues to appear regularly in the media and anti-livestock-production literature.
Many at the time believed the FAO claims were overstated, but it was Mitloehner who, along with some UC-Davis colleagues, investigated the research methods and data behind the conclusions. In 2009, the team published their analysis, titled "Clearing the Air: Livestock's Contributions to Climate Change," in the peer-reviewed journal Advances in Agronomy.
The FAO figures were based on a “lifecycle analysis,” which is intended to quantify all the GHG emissions generated across an entire industry or production process. Mitloehner outlined three approaches to a lifecycle analysis for greenhouse-gas emissions. The simplest form, called LCA-1, measures only direct emissions, such as those from a bovine’s rumen fermentation, manure and urine. A more comprehensive analysis called LCA-2 measures direct, plus indirect emissions such as those from processing, transportation and deforestation associated with livestock production. The most complete analysis, LCA-3, would include direct and indirect emissions from livestock, plus indirect emissions from associated activities, such as production of fertilizer and pesticides used in the production of feed crops.
With that background, he points out that authors of the U.N. report committed some glaring errors. First, in their estimates of emissions from livestock production, they used the full LCA-3, including all direct and indirect emissions from the entire production cycle. That would be fine, except that in analyzing the transport sector they used the simple LCA-1, measuring tailpipe emissions only. That led to the grossly inflated 18 percent figure and the pervasive falsehood that livestock accounts for more emissions than planes, trains and automobiles.
Mitloehner’s research has found that, in the U.S., raising livestock accounts for 3.4 percent of greenhouse gas emissions nationwide, while the nation’s transportation sector contributes roughly 26 percent.