Study: Livestock Methane Emissions Are Much Higher Than Thought
There may be some problems with the way methane emissions have been measured in the past.
Methane is not quite as abundant, as far as greenhouse gases go, as carbon dioxide—but it is much more efficient at trapping heat.
The EPA estimated, in 2019, that about 27 percent of methane emissions came from enteric fermentation (this means, largely, cattle burps) and a further nine percent came from manure management. That’s a substantial amount of the total methane emissions each year. But a new study from NYU and Johns Hopkins University suggests there may be some problems with the way methane emissions are actually measured—and that the amount of emissions might be higher than what existing numbers show.
The study looks into a basic question: how are methane emissions measured and are those measurements accurate? “Present-day estimates of total GHG emissions in a given region are rarely measured directly,” the study reads. Instead, they’re measured using models, extrapolating a little bit of information outward to document larger areas.
The researchers refer to this as a “bottom-up” method, using information gleaned on the ground, rather than in the air. At a very basic level, this can involve measuring the methane emissions of one animal and then multiplying that by the number of animals. But things can quickly get much more complicated than that. There are essentially an endless number of variables from what the animals are fed and how much they move, to how close they are to each other.
Adding more of these variables, if you’re going to multiply them to try to see a larger pattern, can either introduce more accuracy or throw off your numbers entirely.There’s no easy way to know which you’ve got.
The researchers in this study suggest using bottom-up methods in concert with top-down methods. Those latter methods involve actually measuring the amount of methane in the air, which seems obvious, but comes with its own big limitations. For one thing, it’s expensive; you’d have to use airplanes, satellites and sensors on tall towers and those measurements can be thrown off by wind and weather patterns. For another, it’s pretty effective at measuring the amount of methane in the air, but not very good at distinguishing where that methane came from.
But this study—a survey, really, of existing research—notes that studies comparing bottom-up and top-down measurements sometimes have huge gaps between results. Interestingly, the researchers find that globally, those measurements aren’t really so different. But in the United States, it can be vast. “At least four top-down estimates of the contiguous US, representative of emissions occurring over at least one full year, indicate that direct animal methane emissions are 39 percent–90 percent higher than bottom-up models predict,” reads the study.
It’s not exactly clear why the US’s system, which in its industrialized efficiency and density is unusual globally, would have this discrepancy. It’s possibly due, the researchers write, to increased disease among American livestock. Some digestive diseases have also been shown to increase methane emissions. The big concern here is that the UN’s FAO projections are based on these bottom-up measurements. But if more and more operations are industrialized in the American fashion in, just for example, China, we might be dramatically underestimating how much methane livestock is producing.
Follow us
Republish!
Republish our articles for free, online or in print, under a Creative Commons license.
Republish this article
This work is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International License.
Want to republish a Modern Farmer story?
We are happy for Modern Farmer stories to be shared, and encourage you to republish our articles for your audience. When doing so, we ask that you follow these guidelines:
Please credit us and our writers
For the author byline, please use “Author Name, Modern Farmer.” At the top of our stories, if on the web, please include this text and link: “This story was originally published by Modern Farmer.”
Please make sure to include a link back to either our home page or the article URL.
At the bottom of the story, please include the following text:
“Modern Farmer is a nonprofit initiative dedicated to raising awareness and catalyzing action at the intersection of food, agriculture, and society. Read more at <link>Modern Farmer</link>.”
Use our widget
We’d like to be able to track our stories, so we ask that if you republish our content, you do so using our widget (located on the left hand side of the article). The HTML code has a built-in tracker that tells us the data and domain where the story was published, as well as view counts.
Check the image requirements
It’s your responsibility to confirm you're licensed to republish images in our articles. Some images, such as those from commercial providers, don't allow their images to be republished without permission or payment. Copyright terms are generally listed in the image caption and attribution. You are welcome to omit our images or substitute with your own. Charts and interactive graphics follow the same rules.
Don’t change too much. Or, ask us first.
Articles must be republished in their entirety. It’s okay to change references to time (“today” to “yesterday”) or location (“Iowa City, IA” to “here”). But please keep everything else the same.
If you feel strongly that a more material edit needs to be made, get in touch with us at [email protected]. We’re happy to discuss it with the original author, but we must have prior approval for changes before publication.
Special cases
-
Extracts. You may run the first few lines or paragraphs of the article and then say: “Read the full article at Modern Farmer” with a link back to the original article.
-
Quotes. You may quote authors provided you include a link back to the article URL.
-
Translations. These require writer approval. To inquire about translation of a Modern Farmer article, contact us at [email protected]
-
Signed consent / copyright release forms. These are not required, provided you are following these guidelines.
-
Print. Articles can be republished in print under these same rules, with the exception that you do not need to include the links.
Tag us
When sharing the story on social media, please tag us using the following: - Twitter (@ModFarm) - Facebook (@ModernFarmerMedia) - Instagram (@modfarm)
Use our content respectfully
Modern Farmer is a nonprofit and as such we share our content for free and in good faith in order to reach new audiences. Respectfully,
-
No selling ads against our stories. It’s okay to put our stories on pages with ads.
-
Don’t republish our material wholesale, or automatically; you need to select stories to be republished individually.
-
You have no rights to sell, license, syndicate, or otherwise represent yourself as the authorized owner of our material to any third parties. This means that you cannot actively publish or submit our work for syndication to third party platforms or apps like Apple News or Google News. We understand that publishers cannot fully control when certain third parties automatically summarize or crawl content from publishers’ own sites.
Keep in touch
We want to hear from you if you love Modern Farmer content, have a collaboration idea, or anything else to share. As a nonprofit outlet, we work in service of our community and are always open to comments, feedback, and ideas. Contact us at [email protected].Study: Livestock Methane Emissions Are Much Higher Than Thought
by Dan Nosowitz, Modern Farmer
June 7, 2021
Modern Farmer Weekly
Solutions Hub
Innovations, ideas and inspiration. Actionable solutions for a resilient food system.
ExploreShare With Us
We want to hear from Modern Farmer readers who have thoughtful commentary, actionable solutions, or helpful ideas to share.
Submit
This all may be true, but are we also measuring the methane reducing capacity of the methanophagic soil microbes which are fed by the waste from these animals? There were millions of bison grazing the Midwest for millennia and there was no methane toxicity or surplus, as far as we can tell. It seems the methane abundance problem arose after this… after we started killing our soils with pesticides, herbicides, over-tilling, etc.
I believe this is a soil problem, not a livestock problem.