I’ve been asked a number of times why I advocate for cattle grazing in prairies when cattle are such strong contributors to greenhouse gas emissions and rapid climate change. It’s a fair question, but also a complicated one. I don’t have a definitive answer, but I can share some of what makes it a thought-provoking subject. Rather than providing a lot of specific research citations, I’m aiming instead to provide some general information that highlights the complexity of the topic. Feel free to contribute additional information and perspectives in the comments section below (as long as you keep it constructive and polite).
Cattle graze among leadplant and prairie clover at Konza Prairie in the Kansas Flint Hills. What are the ramifications of cattle grazing for greenhouse gas emissions and other contributing factors to climate change?
Cattle: The Downsides
First, here are some reasons people are concerned about the impact of cattle on climate change. According to the EPA, agriculture is responsible for about 9% of the U.S. greenhouse gas emissions, and beef production makes the largest contribution to that category. Most of the impact comes not from carbon emissions, but from methane and nitrous oxide, both of which influence climate change more strongly (pound for pound) than does carbon. “Enteric methane” (cow burps) is a big part of that equation, but so is manure, urine, and application of fertilizers to pastures. These emissions are bad enough, but there are other negative impacts from beef production as well, including emissions from growing corn and other feed for cattle, emissions from manure in feedlots, water consumption by cattle and feed production, and pollution from sedimentation and nutrient runoff of pastureland. Reading a list of bad stuff like this, it’s easy to see how people might wonder why I keep talking about grazing like it’s a good thing.
Cattle are sometimes their own worst enemy in terms of advocating for their own existence. I mean, come on, man! This is just not a good look.
Predecessors to Cattle
As I provide some counterpoints, I’m going to do so from the perspective of the central Great Plains – the area of the world I’m most familiar with. Outside the Great Plains, the situation varies greatly; there are places in the world where grazing may not be compatible with local ecosystems, for example, and where forest or other land cover types are being converted to pasture. Here in my part of the country, however, we are in the heart of the historic bison range. Before Europeans entered the picture in the Great Plains, prairies here were being grazed by bison, elk, pronghorn, and other large animals. There are many arguments about the size of those historic bison populations, fluctuations in herd size and geographic range over time, and when/where bison impacts were important for prairie ecology. For the purposes of this discussion, the important point is that cattle (and their emissions) weren’t introduced into a landscape with no history of methane emissions. Bison were here prior to cattle, and they burped too.
The most cited article I’ve seen on the issue of methane emissions from historic bison populations is by Francis Kelliher and Harry Clark. They use a fairly standard estimate of 30 million bison across the Great Plains prior to European contact. Based on their calculations, the methane (CH4) emissions from those bison (2.2 Tg CH4 year-1) are not hugely different from those of today’s 36.5 million cattle across the same geography (2.5 Tg CH4 year-1). The exact numbers are less important than this basic idea: the prairie ecosystem was contributing large amounts of methane to the atmosphere before humans brought cattle to the Plains.
Of course, feedlots, fertilization, and forage production, along with all the greenhouse gas emissions and other concerns associated with them, were not part of the historic bison landscape. We definitely have an obligation to examine those aspects of cattle production and do what we can to limit their negative impacts. In addition, the fact that cattle on native rangeland are producing emissions similar to their bison predecessors doesn’t release us from the responsibility of trying to reduce those emissions where possible. I’m hopeful that research over the next decade or so will provide us with more guidance on how we might do that.
Before there were cattle, bison roamed (and burped) across the Plains.
Get Rid of Cattle?
What if we just stopped grazing cattle on the Great Plains? Well, since the vast majority of the Great Plains is privately owned, grassland still exists primarily because it produces income. Without cattle production, much of that grassland would likely be converted to row crop agriculture – a scenario that would probably be worse for climate change and would certainly spell disaster for prairie ecosystems. Some have argued that a majority of the Great Plains should be turned into public land that would support both wildlife and tourism. There are way too many economic and social issues associated with that for me to deal with here, but from a climate change emissions standpoint, I’m not sure it would solve the problem. Either cattle would be replaced by bison again (see previous paragraph) or, if bison were not reintroduced, prairies would suffer from the loss of grazing, a major component of ecosystem function (see next paragraphs).
Simply getting rid of cattle altogether is probably not a great strategy for conservation. Besides, how could you get rid of something this cute?
Grazing as a Positive Force
Despite the fact that chronic overgrazing can cause degradation of prairies (loss of plant species and habitat, soil erosion, etc.), grasslands and large grazers evolved together and grazing is still an essential component of grassland ecosystems. This is especially true in North America’s Great Plains where there are still grasslands large enough to support wide-ranging wildlife species such as grouse and pronghorn. Grazing, along with fire and drought, is one of the three major forces that affects prairies and prairie species. For example, large herbivore grazing helps keep grasses from being so competitive that they overwhelm and reduce the diversity of plant communities, something that leads to a cascade of negative and interconnected impacts on pollinators, productivity, wildlife/insect communities, and more. In addition, grazing alters vegetation structure, creating a wide range of habitat conditions. Ungrazed prairie provides fairly uniform vegetation structure, even if it is hayed or burned. Grazed prairie (under the right management) is heterogeneous, with patches of tall/dense vegetation, patches of short/sparse vegetation, and many other habitat types in-between – allowing the widest possible spectrum of prairie wildlife and insect species to thrive.
Maintaining plant and animal diversity, ecosystem function, and ecological resilience within the historic range of American bison would be very difficult without some kind of large ruminant, and in the face of climate change, we need our grasslands to be as resilient as possible. Resilient grasslands will better adapt and maintain their ecological functions as climate changes, and that means they’ll continue to pull carbon from the atmosphere and store it belowground – an incredibly important part of our global climate change strategy. While the impact of grazing on carbon storage of grasslands is, in itself, a complex topic, the general scientific consensus seems to be that a moderate level of grazing facilitates more carbon storage than no grazing (and more than chronic overgrazing).
Strategic cattle grazing can create a variety of wildlife habitat structure types and help sustain plant diversity and ecological diversity. It can also help maximize carbon storage in grasslands.
The Upshot
In the Great Plains of North America, grazing is an essential part of grassland ecosystems – a component that maintains the ecological health and resilience of prairies. Cattle have mostly replaced bison as the large ruminant on stage at the moment, but they are filling many of the same basic roles – regulating plant competition and creating wildlife habitat, and also pooping, peeing, and burping. We absolutely need to find ways to minimize the impacts of today’s grazing on climate change. Livestock confinement operations, pasture fertilization, forage production, and other related practices provide opportunities for continued improvement. In addition, some rangeland grazing practices, such as chronic overgrazing, are known to be detrimental, and not just from a climate change standpoint, so that’s an obvious place to focus. Beyond that, we need to figure out how best to limit methane and nitrous oxide emissions and increase carbon storage on rangeland. That will likely mean changing techniques for managing cattle in pastures, but also dealing with issues related to pasture fertilization, forage production, forage and animal transportation, feeding operations, and more.
The topic of cattle grazing and climate change is incredibly complex. There is much more involved than I could possibly cover here, and what I did include is plenty complicated. I don’t pretend to fully understand all the facets of the issue, but for now, I feel comfortable in my stance that cattle (and/or bison) grazing can be compatible with responsible conservation of our prairies here in the Great Plains.
More Information and Acknowledgements
Several scientists from The Nature Conservancy wrote a really helpful piece on the beef supply-chain and its impacts on water, wildlife, and climate. You can see a summary and get access to the full report here.
Special thanks to Jon Fisher and Joe Fargione, who both helped me refine and improve this post. Any remaining errors are my fault, not theirs.
The Prairie Ecologist 
Bring back the Bison!
How much more natural can you get than cattle grazing freely in an open field? Worry about and think a cow’s “burp” is causing climate change? Please.
people are all ways looking for simple causes…may be the problem is too many people, not too many cows…Iowa farm person…
Well stated — large ranchlands are some of the best conservation properties around. Wildlife depend on unchanged grasslands — and those grasslands exist for cattle to eat (as well as antelope, deer, etc.) The old adage “Cows, not Condos” is still true– and while it might not be “condos” in Nebraska (as it would be in Colorado), it might very well be row crops — which are far less nurturing for wildlife.
Those that are very worried about cattle and the way they are produced in America should abstain from eating grain-fed beef that are finished in feedlots, and support grass fed beef that keeps all that open land open.
Cattle do indeed replace the bison of yore.
I loved reading this post — it’s a common-sense approach to a complex problem, and (even though I’m not a scientist myself) I understood the principles and will remember them.
Perhaps you can clarify one scientific issue, Chris. Has anyone studied how much methane a cow produces when grazing on pasture grass versus when fed on grain (generally corn, presumably)? I suspect that the values would be different per pound of feed, but I cannot recall seeing such data. In general, I would prefer bison to cows (because they graze differently than cattle), pasture fed and finished cattle to grain fed or finished cattle (particularly CAFOs), and perennial grasslands to annual row crops. If cattle are grazed on pasture, they should be excluded from wetlands and riparian areas, and should be stocked at a rate and/or rotated in such a way that avoids overgrazing. The grazing scheme should pass muster by a grassland and wildlife ecologist, and should allow suffficient remaining grass to support other native herbivores. Happy to pay a little more for beef raised that way, and would support labeling laws that would clearly identify it as such to let me choose accordingly.
Patrick, it is (again) complicated. If you have a few minutes, take a look at the full report I linked to at the end of the post. If you skip to the section about greenhouse gas emissions, it talks about how methane production by cattle is actually lower in feedlots because (they think) of higher feed quality. My impression is that cattle can more efficiently process the kind of feed they get in feedlots, producing less methane along the way. That doesn’t mean, of course, we should do all our beef production strictly in confinement systems, or even that confinement systems are automatically more environmentally friendly – there are plenty of issues with confinement, including that (I think?) manure in confinement systems produces more methane (or nitrous oxide?) because of more anaerobic conditions – but I’m getting myself on thin ice here. Regardless, there are definitely many more issues with confinement that can have serious environmental issues, outside of just GHG emissions, so I’m not certainly not advocating for confinement operations. I appreciate a good grass-finished steak myself, although I find that I can’t always afford it.
Well for the record I wouldn’t make a decision of CAFO vs range fed based on methane emissions only….plenty of more important reasons to phase out CAFOs, both environmentally and ethically (some of which you mention above) to tip the balance toward grass-fed, even if methane emissions are slightly higher than with CAFOs.
Unfortunately, as Chris said it is complicated. From a strict GHG perspective grass-finished cattle is generally worse both because b/c of the feed quality issue Chris mentioned, but also because it takes a lot more time for the cattle to reach slaughter weight (meaning it’s producing more methane and manure for longer). That being said there are plenty of issues with feedlots including animal welfare, water quality, and GHGs from the manure pits. But saying grass-finished beef is unilaterally environmentally preferable to grain-finished beef is not supported by the evidence. (note: I’m one of the authors of the report Chris mentioned, and I work at The Nature Conservancy as well).
My concern with the above statement is that grass feed beef requires much less fossil fuel input than grain fed beef. Your points about grass fed beef producing more methane makes sense. However, methane has a relatively short half-life and the methane produced from grass fed beef is a part of a continuing natural cycle. The emissions created in producing the grain that allows grain fed beef to be less expensive are ever adding more greenhouse gases instead of cycling ones that are already present.
The above being said, I can sympathize with Chris when he says about grass fed beef that “…I can’t always afford it.” I personally I only have steak for special occasions a few times a year when visiting family.
Sometimes I think you must have been reincarnated from a cow. :) I also sometimes wonder if any of Nebraska has escaped prolonged intensive grazing so a comparison between original prairie verses different grazing regimes could occur.
The problem of global warming is too big to be solved by any one answer. This includes hating cows. We will need a market based solution. If ranchers defend carbon emission allotments with the zeal that they defend their fence lines then I think we might have a chance of solving this problem.
Thanks for this post Chris. I have read that grasslands managed with fire store more carbon than grasslands managed without fire, but, until reading your post, was not familiar with the notion that moderate levels of grazing facilitate more carbon storage than no grazing. Can you expand on this a bit?
In general, all folks involved in sustainable methods of land use need to stop beating up on each other.
David
Hi David,
As I said in the post, I’m not an expert in any of this. My impression (and that’s all it is because I don’t know the literature well) is that moderate grazing increases carbon storage because of increased vegetation growth and turnover of roots. The carbon put into the soil comes from plant roots that turn into soil. I’ve read somewhere that something like 30% of prairie roots decompose each year. Without grazing, shade from thatch inhibits growth of plants, both above and belowground, and that includes root growth. Fewer smaller roots turn into less carbon going into the soil. With overgrazing, the same thing happens for different reasons. Repeated grazing doesn’t allow plants to produce aboveground biomass, which restricts their belowground biomass too, resulting in fewer roots and less carbon going into the soil. Moderate grazing splits the difference. It reduces vegetation aboveground enough that it allows more light to hit the ground but doesn’t injure plants enough that they can’t still grow strongly. The result is more root production than either no grazing (assuming no fire or mowing also, of course) or overgrazing. Now, I also think there is MUCH to still learn on this topic, so I don’t think we want to read too much into this right now.
Thanks!
I agree that grazing cattle on the Great Plains is a minor problem in the overall catastrophe of climate change. The real cause that everyone wants to dance around is our modern lifestyles. This dance with the devil will continue because, as Dick Cheney said, “The American way of life is non-negotiable.” We don’t want to acknowledge that sentiment and its implications. Instead we want to pick out bogey men and point the finger outward instead of pointing it back to us. It’s livestock; it’s China; it’s politics, etc. We will continue to drive our vehicles until we can’t. We will continue to eat meat until we can’t. We continue to use electricity and natural gas until we can’t. Again grazing cattle on the Great Plains is minuscule in comparison. That said, we will continue grazing cattle until we can’t.
Pleased to see that someone in the United States is still concerned about the environment and hadn’t been muzzled. Good post, Chris. Thank you.
Good post Chris. I would like to add two very important points. First, you did not state the fact that methanotrophs have the ability to utilize the majority of the methane from grazing ruminants (in a healthy functioning ecosystem). This is why methane is not and will not be an issue where livestock are grazed properly. Second point is that if one understands how soil functions they will understand that grazing animals are critical for this function which includes the cycling of carbon. Most do not understand that the ONLY and BEST option to take CO2 out of the atmosphere and put it back in the cycle is with grazing ruminants. The problem is NOT cows, the problem is that we have largely removed them from the landscape and put them in confinement situations where the then cannot perform the proper function.
My understanding has been that grazing cycles carbon, but prairie soil does not sequester carbon beyond certain levels. Do you know of studies that have found grazing causes grasslands to continue to accumulate carbon? If soil accumulates carbon slowly, would the rate be large enough to make a difference in the face of human caused global warming? I have always thought the biggest benefit of grazing was it prevented the carbon already in the soil from being released by cultivation.
Do you have any citations for this? I’m not clear how methanotrophs in the soil could abate enteric methane emitted by cows 1-2 meters up, but I’d be curious to learn more.
http://onpasture.com/2017/01/30/surprising-news-about-deep-soil-carbon/
Jon
I saw this article this week. The citation is at the bottom. Seems to me that carbon storage would have to reach some equilibrium in prairie soils just as it does in peat bogs, forests and other ecosystems. I would suggest that prairies hold more carbon than many other ecosystems with original soil organic matter levels in the Midwestern U.S. reported at near 8%. With the corn ecosystem now in place we’ve mined carbon down to 2% more or less. Properly managed grazing should restore that carbon over time and continued grazing should keep it there versus the millions of acres in the Midwest lost from grasslands to corn/beans in the last 10 years.
I agree with Chris that we need to be careful about being caught running with sharp pencils and how that makes other livestock producers look. Haven’t seen you since Austin and hope to see you both again soon.
The following sentence from the article in the link is interesting.
“These baseline samples showed that soil organic carbon levels varied within the first foot of the subsoil by as much as around 18 tons per acre, while soil carbon levels 5 feet below the soil surface varied by as much as almost 90 tons per acre.”
The article’s central result is a “statistically significant” increase “that exceeded 0.9 ton per acre.” However, the difference of 90 tons per acre 5 feet below the soil surface seems to be much more important. Scientists should try to understand why some soils store so much more carbon and if landowners could do something to increase soil carbon storage capacity. Of course, landowners who stored more carbon would deserve to be paid by those who emit it.
agree with comments above: our most common beef production in feedlots includes grain that is poorly digested yielding faster weight gain and more fat. The healthy aspects of people consuming beef that roamed over grasslands instead of feedlots is well documented. Close the feedlots not the operations that rely on open meadows. Good depiction of crossing over our intensely divided political perspectives to yield better ecological results in the book “Rancher, Farmer, Fisherman”.
Thanks for another useful post, Chis. As a landowner in the process of converting row-crop ground to grazing, I appreciate the positive reenforcement along the lines of environmental benefits. There are (or will be) economic benefits as well. Humans are part of the ecosystem.
For those that look to science; using a life cycle assessment of grazed beef, Rowntree etal. 2016, found “when soil carbon sequestration potential was included, each grazing strategy could be an overall (carbon) sink”. Looking at a stock density (live animal weight) of 88,000 lbs/ac dryland and 25,500 lbs per ac irrigated.
For those looking to nature; the split hoof of large grazing herbivores creates a disturbance at the soil surface unlike anything man can create (tilling, chopping and kinetic energy). This does not even consider the biologics being dumped on both ends of this walking, mooing, ruminating microbial fermentation vat. Disturbance is followed by rest as the herd moves on.
Disclaimer: We are Grassfed beef producers grazing prairies and forestlands in SE Nebraska since 2011 and have lots to learn, that is why we follow Chris. Consider establishing Soil Carbon monitoring sites following Peter Donovan’s Soil Carbon Challenge protocol in the prairie you manage.
Rowntree – http://www.futureoffoodjournal.org/index.php/journal/article/view/232/pdf
Your story is an often commented to support cattle grazing but it is too similar to textbook justification. In college I was taught that proper cattle rotation would produce a diverse prairie for wildlife. This is almost never the situation in the real world. Here in Texas for example. People drive by range lands and see grasses and say “Look, all that grass and wildflowers” but take a close look and you’ll see nothing but exotic flora that has not evolved with the local wildlife. A closer look will show severely compacted ground, spoiled riparian areas and unsafe nesting sites due to hoof action. Grazing rotation can work but in a highly controlled situation. It is very labor intensive and that cuts into the bottom line for a rancher/farmer that lives on the financial edge every year (and that’s with subsidies from the federal and state governments).
Thomas, I’ve seen situations like the one you cite too, but that’s not the way of things in many other places. Most of the most effective grazing I’ve seen (in terms of creating good wildlife habitat and sustaining plant diversity) is not the kind of intensively managed grazing you mention, but much less intensive, with a few pasture moves a year or something like patch-burn grazing that encourages intensive grazing in some places but long rests in others (and changes the location of each treatment annually). So, I agree with you that chronic overgrazing can do bad things, including all the ones you mention, but don’t paint with such a broad brush. Saying cattle grazing is bad because some people overgraze is like saying food is bad because some people overeat. There are some great examples of cattle-grazed prairies that are diverse in both flora and fauna. If you read other posts of mine on grazing, you’ll see that I advocate for cattle (and bison) grazing that is compatible with conservation, and that I have data and documentation that it can work. If you’re in Nebraska sometime, stop by the Platte River Prairies or Niobrara Valley Preserve and take a look for yourself. Thanks for the comment.
In the spirit of fairness, all the remnant prairies I know of locally are not grazed by cattle but are constantly under threat from one or more invasive species. I have heard anecdotal evidence that a history of grazing has caused species like smooth brome or reed canary grass to increase. However, the problem of invasive species is still a significant threat even when no cattle grazing is occurring.
Thanks Chris. I would think annual tillage is way worse for our soils and climate than cattle grazing on grass pastures.
Excellent discourse, thank you for taking on this topic.
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Great post! I have recently moved to MN to develop a conservation Grazing program for a prairie restoration company, using bison, cattle, sheep and goats for various ecological goals. Your posts have been very helpful to me as I’m getting my footing here in the prairie. Thanks and keep them coming!