A new report suggests that grass-fed beef offers fewer climate benefits than promised, but the debate rages on.
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A new report suggests that grass-fed beef offers fewer climate benefits than promised, but the debate rages on.
November 13, 2017
For much of the past decade, it’s been widely reported that cattle are among the planet’s biggest climate-changing culprits. A 2010 report from the Environmental Working Group showed that cattle release large amounts of methane into the atmosphere, greatly increasing the impact of meat on greenhouse gas emissions. Some ranchers and other experts, including ecologist Allan Savory, have countered that carefully managed grazing on certain land has the potential to sequester carbon in the soil, thereby reducing the amount that’s released into the atmosphere.
Tara Garnett, a food systems analyst and the founder of the Food Climate Research Network (FCRN) at the University of Oxford in England, decided to test this theory. “Savory has quite a following,” said Garnett. “We wanted to find out if he was right.”
This narrow question is the leaping-off point of a new report, two years in the compiling, that seeks to clear up confusion about what Garnett calls “inflated claims” concerning the impacts of grazed-livestock production.
In looking at 300 academic peer-reviewed research papers from the last 20-plus years, Garnett and her co-researchers concluded that the carbon sequestered by raising cattle exclusively on pasture, even if they’re sustainably managed, doesn’t balance out the methane released over the cow’s lifecycle. And although Garnett admits that the limited scope of the report makes it just “one small part of the puzzle” concerning the ecology of food systems, her team’s findings—and the accompanying assertion that reduced meat consumption is the only way for us to meet global climate goals—have nevertheless sparked strong responses, both positive and negative.
“It has been interpreted as though we’re claiming intensive production”—basically, the landless feedlot systems decried by animal welfare groups—“is preferable” to grass-fed, says Garnett, although the report does not reach this conclusion. “All we’re saying is that grass-fed doesn’t constitute a ‘get out of jail free’ card.”
Can grazing be at least part of the answer to the question of how to reduce the climate impact of our food systems? California-based rancher Nicolette Niman, the author of Defending Beef, thinks so. With a preponderance of ranching practices that result in deforestation, overgrazing, and desertification, Niman says the industry as a whole “has a lot of room for improvement.” But, she adds that “we need to focus on how we create sustainable food systems where livestock belong, because 40 percent of our land cannot be used for anything else.”
She’s referring to rangelands that support, and are supported by, ruminants as part of a dynamic ecosystem that’s unsuited to growing crops, which depletes these lands—possibly for good. “I think the biology of soils needs to become a cornerstone of our focus, rather than the amount of outputs, whether soy or grain or meat,” Niman said. And she maintains that grazing is critical to this process: “I don’t necessarily think we should produce more or less meat; we need to produce it better.”
Advancing better standards for beef production is an aim of environmental advocacy group, Natural Resources Defense Council (NRDC). Like Niman, Jonathan Kaplan, NRDC’s director of food and agriculture programs, sees a place in the greater equation for meat—with provisions. “There’s a huge contribution that sustainable grass-fed beef producers are making to the environment,” he said, citing increased grass production and water infiltration, among other benefits. “But at the end of the day, beef has a much bigger environmental footprint [than other foods]—30 times that of lentils, for example.”
Overall, said Kaplan, the FCRN report “authoritatively pokes a hole in arguments from some corners of the sustainable food community that [say] if we just manage cows on sustainable pasture, we can offset emissions with soil-based carbon.”
Michael Coe is a senior researcher at the Woods Hole Research Center in Falmouth, Massachusetts, who studies land management systems in Brazil. The bigger issue for him regarding the FCRN report (which references some of his work) is not its conclusion, but the model it chose to analyze. “We already knew that meat in general is an expensive prospect,” he said.
By looking at ruminants grazing exclusively on grass, Coe said the report “provides a solution to a problem that didn’t exist,” since there’s not an abundance of grass-finished meat. In fact, according to the FCRN report, meat from global grazing systems account for only about 1 gram of protein per person, per day—just a small fraction of what we eat. He believes it’s more important to try to understand how the various parts of the large, complex system of meat production work in conjunction with one another.
On the one hand, Coe agrees with arguments for decreasing meat consumption, “since it will decrease one of the biggest pressures for land use.” On the other, he adds, “I don’t think it will be a panacea.” The looming question is whether cutting livestock production would actually result in decreased demand for land use. “Land is a means of making money,” he said. “Won’t the market simply incentivize some other use, like growing biofuels?”
FCRS’s Garnett maintains that the aim of the report wasn’t to address these broader implications, but simply to provide an answer to one simple question that other researchers can “layer” their work on top of, to create a more complete picture. She and her team also hope to complete similarly in-depth studies of other meat production systems, as well as of land use.
With the grazing report, “we wanted to follow through on one issue from start to finish,” Garnett said. But ultimately, she says,“There are a whole range of concerns: How does the grass-fed issue slot into the diets issue, then into sustainable consumption patterns, then into climate change? How do we define progress? Where do we want to go?”
Her conclusion in the aftermath of the report is that consumers who’ve banked on the positive climate effects of eating 100-percent pasture-raised beef will still need to consider eating less meat after all.
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Garnett/FCRN's 127 report basically states the following:
Carbon sequestration/storage levels don't offset enteric methane and nitrous oxide emissions. There is some carbon sequestration/storage, but higher levels reported aren't true. Moreover carbon sequestration levels are limited. That sequestration/storage caps out so there are diminishing returns as carbon is sequestered. Thus as this occurs, even more methane and nitrous oxide are omitted because there is less of a carbon offset. Since grass finished cattle live longer, they emit more methane and therefore are less environmentally friendly than feedlot finished cattle from strictly a GHG point of view. Though there are other significant issues with intensified operations for feedlot finished cattle, and other meats. Therefore we should eat more vegetables and vat-meats because this takes up less land and emits fewer GHG’s. Additionally, grasslands should be allowed to all become forests or used for bio-energy production
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During the entire 127 page report the terms "soil health", "soil ecosystem", soil microbes" and "topsoil loss" aren't mentioned at all even though soil carbon capture and respiration rates are completely dependent on the soil's health and microbiology as many of the more progressive soil scientists like Dr. David C Johnson, Dr. Christine Jones, Dr. Elaine Ingham as well as geologist Dr. David Montgomery and author Graeme Sait have pointed out in their research and or writings.
Here's a brief discussion about this impact of soil health on carbon capture from Dr. Johnson in this video https://youtu.be/Fdh_j_KOmrY and more at length discussion in these presentations https://youtu.be/XlB4QSEMzdg and https://youtu.be/18FVVYKU9gs
Basically Johnson notes that with healthier soils that have more fungi than bacteria, there is significantly more carbon capture (10+ times) and less carbon respiration. Long rooted perennial systems also pull carbon down deeper into the soil where the carbon is less volatile. Additionally, Johnson notes that, while there is a limit to how much carbon soil can store/sequester, there is no limit to how much soil that can be built. So more soil equals more carbon sequestration.
Given how rapidly soil is being lost (some projections note the planet will lose all of its top soil in 60 years), building new top soil is incredibly important. Relying solely on geology, building new topsoil takes over 100 years to build from the bottom up. But with composting, soil can be built more quickly from the top down. What do ruminants do? They are nature's mowers, composters and spreaders. Well managed ruminants, especially in more arid brittle environments with seasonal humidity are the best way to build more healthy topsoil the most rapidly as Gabe Brown points out in this video, Keys to Building Healthy Soil, https://youtu.be/9yPjoh9YJMk Soils with animals manures have the most and greatest microbial diversity and soil is made largely from dead microbes, not deteriorating organic matter. So the greater and more diverse the soil microbial mix the better for building soil.
Now what else do healthy soils do? They increase water infiltration and retention. So healthy soil ecosystems improve drought resistance and therefore increases plant growth. With more plant growth, there is more evapotranspiration, and thus healthy soils actually increase rainfall. With no-till systems and continuous cover, more moisture in the soil improves the soil ecosystem for methantrophic activity. With more rain, and moisture, some of those methanotrophs become airborne. So methanotrophs in the soils, mitigate CH4 emissions from manure and airborne methanotrophs mitigate enteric methane in the atmosphere. Moreover, other soil microbes make sure more of the nitrogen (urea) in the manure is broken down into forms of nitrogen that plants can use like NH4 rather than are emitted into the atmosphere like nitrous oxide N2O. This natural occurring nitrogen doesn't leech into the environment like synthetic nitrogen that plants only utilize a small fraction of for growth. Most synthetic N runs off compacted soils into waterways causing aquatic hypoxia (dead zones).
Healthy soils are the key to everything, so it was quite shocking that this report completely overlooked this topic. Holistic management is not simply another grazing system for moving cattle. No, holistic management is a systems approach to regenerating land/soil health, ecosystem function and economic well being.
The solutions to let grasslands all become forests was quite comical as well, since most of the planet's grasslands are in brittle environments with little rain fall or seasonal humidity, so unless you improve soil health, most trees will die. Moreover from an ecological history point of view, most grasslands weren't forests. Grasslands co-evolved with large megafauna , grazing ruminants, and apex predators. When mankind helped kill off the megafuana, he became the keystone species who used controlled burning to reduce plant succession. Converting grasslands to bioenergy crops is even more absurd....because this is what's actually happening and leading to the destruction of drought resistant biodiverse grasslands with monocrops of blue water dependent seed oil crops used for ethanol, biofuels, processed food ingredients, cooking oils, industrial products and CAFO feeds. FCRN's suggestions for alternative grassland uses, in other words, are just plain dumb.
There are many other shortcomings with FCRN's report, though the lack of discussion of soil science and soil health's role in GHG balances, as discussed above, is the most glaring and egregious one.
Best,
Tyler
As for the extent of carbon capture and respiration, when you peruse the older science , yes based on statistical averaging you have to concur with their conclusions (as well as many others who have made the same or similar conclusions) that soil doesn’t capture as much carbon as many optimistically claim that it does... as well as that a lot of this captured carbon isn’t stable. But what all this old data doesn't really account for is all of the recent new soil science regarding soil microbiology. This new science changes a lot of what we think we knew, and starts to explain why some soils capture more and respire less carbon than other soils.
Dr. David Johnson discusses the impact of soil microbiology on carbon capture and respiration in these videos https://youtu.be/Fdh_j_KOmrY and (longer) https://youtu.be/18FVVYKU9gs Though to date Dr. Johnson hasn't published any research . I believe he will be publishing some research soon. He's part of the Soil Carbon Cowboy team.
Though Johnson hasn't published any research, others have published research that supports what he says in these videos. Johnson's primary message is that soils that contain more fungi capture and retain significantly more carbon than soils that don't. Connecting the dots, one fundamental paper that supports this position is Kallenbach et al 2016 (see link below) which explores soil organic matter formation. This paper shows how the microbiology creates organic matter rather than being created solely by humus. It also shows that soils that contain more fungi utilizes carbon more effectively and respire less carbon. Li et al 2017 also discusses the importance of soil microbiology. Increases in microbial mass increased soil carbon gains. Nichols et al 2013 looks at what field conditions increase fungi, specifically arbuscular mycorrhizal fungi [AMF]. AMF was the greatest in grazing non-till systems. Non-till, diverse cover crops and manure all increased AMF. Conventional tillage decreased it, but interesting conventional tillage with manure had more AMF than conventional till without manures.
AMF takes the carbon from roots and creates glomalin which in turn gives soil structure. AMF taps into root systems and extends those systems farther and deeper into soils. The more AMF the more exchange of exudants for minerals, and the more AMF the more exudants are required. The AMF also goes deeper into the soils extending a plants ability to get to minerals that are made available via other soil microbes. So bottom line the more AMF the more carbon capture, the deeper the capture and less respiration. Continuous ground covers also keep ground surface and soil temperatures down, so there is less respiration than exposed soils no matter how much CO2 is in the atmosphere.
So basically you can't separate carbon utilization, sequestration and respiration from the soil health and soil health is directly tied to the diversity and health of the soil ecosystem. Systems, like well managed grazing systems, that disturb the soil the least are the healthiest. Poorly managed grazing, tillage, and input intensive non-till all undermine soil health. #Itsthesoilbiologystupid.
The problem is that many climate scientist as well as old school soil scientists don't acknowledge the importance of the role that this "hidden half of nature" plays in the way carbon sequestration, nitrification and methane oxidation takes place. They don't seem to realize the big picture is made up of a billion tiny dots. Funny too when soils are covered, and healthy, the ground temp and local micro-climate temps are significantly lower than areas with a lot of exposed soil. A lot of local micro-climates also can have a much larger impact.
Also on a separate note, too many climate scientists seem entirely fixated on CO2 emissions and fail to see other factors impacting earth's surface temperatures...Specifically with more ground covers, mycorrhizal fungi, and carbon in the soil....there will be more plants and thus more evapotranspiration which also results in more micro-climate cooling via more rain. Never ceases to amaze me how compartmentalized many scientists think. So few are system thinkers, and even fewer can connect any dots. They're all learning more detail about less and less.
Bibliography:
Kallenbach et al 2016 Direct evidence for microbial-derived soil organic matter formation and its ecophysiological controls https://www.nature.com/articles/ncomms13630
Li et al 2017 Soil carbon sequestration potential in semi-arid grasslands in the Conservation Reserve Program https://www.researchgate.net/publication/313747580_Soil_carbon_sequestration_potential_in_semi-arid_grasslands_in_the_Conservation_Reserve_Program
Nichols et al 2013 glomalin and soil aggregation under six management systems in the northern great plains usa. open journal of soil science 3-374-378 http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=2471&context=usdaarsfacpub
In addition, renewable energy has already started snow-balling. Electric vehicles will replace the need for biofuels and dropping PV prices will make each home a electricity generator.
Organizations like NRDC, in defending animal agriculture, further confuse the issue by ignoring the science and issuing statements like “There’s a huge contribution that sustainable grass-fed beef producers are making to the environment. But at the end of the day, beef has a much bigger environmental footprint [than other foods]—30 times that of lentils, for example.” So, is beef bad for the environment or not? NRDC cannot seem to decide. Perhaps Mr. Kaplan needs to actually read the FCRN report.
As more and more recent soil science is indicating (e. g. https://www.nature.com/articles/nmicrobiol2017105 ) stable carbon capture is being driven by soil microbiology especially arbuscular mycorrhizal fungi. In order to enhance habitat for all of this microbiology , you need diverse ground cover and minimal ground disturbance....like in grassland ecosystems. Now how do you derive food off of such systems and in integrated non-till systems? With grazing ruminants. And yes, there's a lot of hectares (about 2.8 billion) grassland ecosystems on this planet most of which can't be used for crop production. Ranchers who managed this land well are preserving these ecosystems.
Garnett et al were reading through a lot of the old science not accounting for this paradigm shift in how we understand soils function and utilize carbon (plus don't get saturated). So the only thing that was really confused was Tara and her crew.
On a side note, grazing enhances conditions for methanotrophic activities which mitigates manure methane emissions as well as methane emissions from other natural and anthropogenic sources. Plus enteric methane in the atmosphere gets oxidized by hydroxol radicals in the troposphere so not much of that CH4 gets into the stratosphere. This oxidation is why all the bottom-up methane analysis doesn't match the top down analysis that has been showing the CH4 concentrations aren't from cattle.
To read the actual petition and all the organizations that signed it you can go to this link:
https://citizensagainstequineslaughter.org/2017/11/23/breaking-news-20-environmental-and-wildlife-organizations-have-petitioned-president-trump-sec-of-the-int-zinke-and-congress-to-rectify-the-livestock-grazing-issues-on-public-lands/
Thank you!