As the scale and impacts of climate change become increasingly alarming, meat is a popular target for action. Advocates urge the public to eat less meat to save the environment. Some activists have called for taxing meat to reduce consumption of it.
A key claim underlying these arguments holds that globally, meat production generates more greenhouse gases than the entire transportation sector. However, this claim is demonstrably wrong, as I will show. And its persistence has led to false assumptions about the linkage between meat and climate change.
My research focuses on ways in which animal agriculture affects air quality and climate change. In my view, there are many reasons for either choosing animal protein or opting for a vegetarian selection.
However, foregoing meat and meat products is not the environmental panacea many would have us believe. And if taken to an extreme, it also could have harmful nutritional consequences.
Setting the record straight on meat and greenhouse gases
A healthy portion of meat’s bad rap centers on the assertion that livestock is the largest source of greenhouse gases worldwide. For example, a 2009 analysis published by the Washington, DC-based Worldwatch Institute asserted that 51% of global GHG emissions come from rearing and processing livestock.
According to the US Environmental Protection Agency, the largest sources of US GHG emissions in 2016 were electricity production (28% of total emissions), transportation (28%) and industry (22%). All of agriculture accounted for a total of 9%. All of animal agriculture contributes less than half of this amount, representing3.9% of total US greenhouse gas emissions.
That’s very different from claiming livestock represents as much or more than transportation.
Why the misconception? In 2006 the United Nations Food and Agriculture Organization published a study titled “Livestock’s Long Shadow,” which received widespread international attention. It stated that livestock produced a staggering 18% of the world’s greenhouse gas emissions.
The agency drew a startling conclusion: Livestock was doing more to harm the climate than all modes of transportation combined.
This latter claim was wrong, and has since been corrected by Henning Steinfeld, the report’s senior author. The problem was that FAO analysts used a comprehensive life-cycle assessment to study the climate impact of livestock, but a different method when they analyzed transportation.
For livestock, they considered every factor associated with producing meat. This included emissions from fertilizer production, converting land from forests to pastures, growing feed, and direct emissions from animals (belching and manure) from birth to death.
However, when they looked at transportation’s carbon footprint, they ignored impacts on the climate from manufacturing vehicle materials and parts, assembling vehicles and maintaining roads, bridges, and airports.
Instead, they only considered the exhaust emitted by finished cars, trucks, trains, and planes. As a result, the FAO’s comparison of greenhouse gas emissions from livestock to those from transportation was greatly distorted.
I pointed out this flaw during a speech to fellow scientists in San Francisco on March 22, 2010, which led to a flood of media coverage. To its credit, the FAO immediately owned up to its error. Unfortunately, the agency’s initial claim that livestock was responsible for the lion’s share of world greenhouse gas emissions had already received wide coverage.
To this day, we struggle to “unring” the bell.