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Livestock's Greenhouse Gas Emissions
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It is often claimed that “animal agriculture” is to blame for 51% of greenhouse gas emissions, and releases more than the entire transportation sector. However, the truth is that agriculture as a whole constitutes about 13.5% of all world greenhouse gas emissions. There is some dispute about that number, some say it’s less and some say it’s more depending on what emission sources researchers count as agriculture (does it include forestry? Food processing and handling?). In developed nations, agriculture accounts for less (for example, 9% in the US, 8% in Canada, and 9% in Europe).
Sources supporting the 13.5%: |
Photo from www.climatecolab.org
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"Global Anthropogenic GHG Emissions by Sector." Global Anthropogenic GHG Emissions by Sector | Center for Climate and Energy Solutions. Center for Climate and Energy Solutions, 2005. Web. 27 June 2017.
"Greenhouse Gas Emissions from Agriculture, Forestry, and Other Land Use." Fapri IA State. World Agricultural Outlook, n.d. Web. 27 June 2017.
"Introduction to the Energy Sector and Its Greenhouse Gas Emissions." Introduction to the Energy Sector and Its Greenhouse Gas Emissions | GEOG 438W: Human Dimensions of Global Warming. n.d. Web. 27 June 2017.
Only 27% of that 13.5% (so about 3.6% of all world greenhouse gas emissions) can be linked exclusively to livestock. 20% comes from enteric fermentation, which is the methane release by ruminant animals, especially cattle. The other 7% comes from manure management.
The reason that enteric fermentation is a particular concern for environmentalists is that the gas released is methane, which has a global warming potential 56 times that of carbon dioxide over its first twenty years in the atmosphere, although that number decreases notably as time goes on. Enteric fermentation from livestock accounts for 16% of all world methane emissions.
However, one thing that plant-based activists ignore is that rice cultivation, because so much standing water in the rice fields provides the perfect environment for methane-producing bacteria, is very close behind it at 12%. Furthermore, nitrous oxide, which has a global warming potential that’s 280 times that of carbon dioxide (and five times that of methane), is largely emitted by the nitrogen fertilization of soils. With these two examples, we begin to understand how crop production accounts for the large majority of agriculture’s emissions.
Saying that cattle are the end-all-be-all of agriculture’s emissions is an extremely flawed argument. Beyond just the raw data, it’s notable that the most bovine concentrated regions do not account for large segments of the world’s GHG’s. For example, India, the nation with the largest cattle population represents only 5.7% of all world greenhouse gas emissions. Brazil, who’s second in terms of cattle population, represents 2.6%. The numbers become even more surprising when you consider the landmass size and reliance on agriculture in Brazil and India in comparison to other, more developed nations.
"Greenhouse Gas Emissions from Agriculture, Forestry, and Other Land Use." Fapri IA State. World Agricultural Outlook, n.d. Web. 27 June 2017.
"Introduction to the Energy Sector and Its Greenhouse Gas Emissions." Introduction to the Energy Sector and Its Greenhouse Gas Emissions | GEOG 438W: Human Dimensions of Global Warming. n.d. Web. 27 June 2017.
Only 27% of that 13.5% (so about 3.6% of all world greenhouse gas emissions) can be linked exclusively to livestock. 20% comes from enteric fermentation, which is the methane release by ruminant animals, especially cattle. The other 7% comes from manure management.
The reason that enteric fermentation is a particular concern for environmentalists is that the gas released is methane, which has a global warming potential 56 times that of carbon dioxide over its first twenty years in the atmosphere, although that number decreases notably as time goes on. Enteric fermentation from livestock accounts for 16% of all world methane emissions.
However, one thing that plant-based activists ignore is that rice cultivation, because so much standing water in the rice fields provides the perfect environment for methane-producing bacteria, is very close behind it at 12%. Furthermore, nitrous oxide, which has a global warming potential that’s 280 times that of carbon dioxide (and five times that of methane), is largely emitted by the nitrogen fertilization of soils. With these two examples, we begin to understand how crop production accounts for the large majority of agriculture’s emissions.
Saying that cattle are the end-all-be-all of agriculture’s emissions is an extremely flawed argument. Beyond just the raw data, it’s notable that the most bovine concentrated regions do not account for large segments of the world’s GHG’s. For example, India, the nation with the largest cattle population represents only 5.7% of all world greenhouse gas emissions. Brazil, who’s second in terms of cattle population, represents 2.6%. The numbers become even more surprising when you consider the landmass size and reliance on agriculture in Brazil and India in comparison to other, more developed nations.
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It also adds a twist to the story when you consider the transportation used in shipping agricultural commodities. Because livestock species are so adaptable, they are grown in just about every part of the world. Transportation for this branch of agriculture only accounts of short truck rides to the processing plant then to the grocery store. Crops, on the other hand, are very climate-specific. Most fruits and vegetables are only grown in one latitudinal region, and have to be shipped hundreds (in cases like cocoa or bananas, even thousands) of miles to get to the consumer. Farm animals’ abilities to produce food in even the most arid areas drastically cuts down on their emission potential because they don’t have to be transported as far.
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Photo from www.fueloyal.com
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It can still be argued that agriculture (meaning crops and livestock combined) accounts for more greenhouse gas emissions than transportation. However, as a sector that is used in every single corner of the world (transportation is used primarily in developed nations) and is relied on so heavily by every single person, agriculture should not be penalized as a culprit. Animal welfare activists say, "Livestock cause more emissions than transportation," because transportation is something many people consider very harmful to the environment, but not many people consider how much more extensive the livestock sector is than transportation. Furthermore, agriculturalists are very concerned about the environmental impacts of their work, and what they’re doing to lessen their effects will be a topic of a blog post later in this Sustainability Series.
However, I want to make a bold assertion: there is no such thing as “animal agriculture.” The truth is that all sectors of the agricultural industry are connected and rely on each other. For example, we grow corn for ethanol fuel. We use livestock manure for crop fertilizer (so should manure management be linked into that 27%?). Soil sciences is vital to horticulture, livestock, mining, forestry, and entomology. Because there is no definitive lines between each of these categories, it would be impossible to just do away with one. All branches of agriculture are interdependent on others.
However, I want to make a bold assertion: there is no such thing as “animal agriculture.” The truth is that all sectors of the agricultural industry are connected and rely on each other. For example, we grow corn for ethanol fuel. We use livestock manure for crop fertilizer (so should manure management be linked into that 27%?). Soil sciences is vital to horticulture, livestock, mining, forestry, and entomology. Because there is no definitive lines between each of these categories, it would be impossible to just do away with one. All branches of agriculture are interdependent on others.
