The Green Urbanist

#14: Livestock and Climate Change - Why Cows are not (Necessarily) Evil

January 03, 2021 Ross O'Ceallaigh
The Green Urbanist
#14: Livestock and Climate Change - Why Cows are not (Necessarily) Evil
Show Notes Transcript

Welcome to the Green Urbanist, the podcast for urbanists fighting climate change. I'm Ross.

The premise of this episode is that the way we currently produce most of our meat, using factory farms and feedlots, is a disaster from an environmental point of view and contributes a small but significant amount to global greenhouse gas emissions. However, there is a potential solution to this problem beyond simply eating less meat, which involves managing livestock in such a way that it contributes to ecosystem restoration and carbon sequestration in soil. That's why the title of this episode is Why Cows aren't Necessarily Evil.

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Sources for this episode:

Stanley et al (2018) Impacts of soil carbon sequestration on life cycle greenhouse gas emissions in Midwestern USA beef finishing systems (,to%20a%20new%20genetic%20study.

FAO - Tackling Climate Change through Livestock (

Rodgers and Wolf (2020) Sacred Cow: The Case for Better Meat (Book)

Welcome to the green urbanist, the podcast for urbanists fighting climate change. I'm Ross.

In today's episode I'm broaching a pretty controversial and touchy subject, which is the meat industry. I'm going to throw in a caveat right now that this episode isn't about picking sides in an argument or criticising anyone's diet or moral standpoint. I'm not going to talk about nutrition or anything like that. That being said, you may find this episode challenging. Some of you listening may be vegetarian or vegan and some of you may eat a lot of meat and not think twice about it. People in both of these groups will likely be challenged by today's episode, so I really don't expect to have many listeners left after this. I just hope that you can get something from this that will deepen your understanding of a very complex issue.

This podcast is all about taking topics around sustainability and climate change and saying, actually this is more complicated than you might think, and taking a deep dive into the science. That's exactly what we are doing with today's episode. So, I'll tell you the fundamental premise of the argument upfront and then we can get into all the details.

The premise of this episode is that the way we currently produce most of our meat, using factory farms and feedlots, is a disaster from an environmental point of view and contributes a small but significant amount to global greenhouse gas emissions. However, there is a potential solution to this problem beyond simply eating less meat, which involves managing livestock in such a way that it contributes to ecosystem restoration and carbon sequestration in soil. That's why the title of this episode is Why Cows aren't Necessarily Evil.

I should say now that none of the ideas I am putting forward are my own - they all come from research and reading about what other people are doing. Of course all the references are in the podcast description if you want to do some more reading. Another thing to mention is I use a small number of examples in this episode. In reality there are a lot of people using  a similar approach, sometimes using different names, in lots of places around the world. Although it is still a very niche approach.

The Figures

We have all been told that one of the leading causes of greenhouse gas emissions and therefore climate change is livestock farming - particularly cows. And the only way to solve this problem is if we all eat less meat. Or if we do eat meat, at least don't eat beef because cows are the worst offenders. Reducing our global meat consumption will go a long way to tackling climate change, we hear.

When we are told to eat less meat, that is a simple message, a very simple solution to an incredibly complex problem. I've been doing a lot of reading on this subject lately and I just want to bring some fresh thinking into this topic so we can understand that it's maybe not as simple as all that.

So, why is livestock farming so harmful to the environment? There are lots of figures floating around about what percentage of global emissions are caused by livestock, with some people claiming that the industry is responsible for 50% of the world's emissions, and is even worse than the transport sector. If you actually go deeper and read the scientific literature, you find that these figures are actually discredited and simply not true. They stem from a misrepresentation of calculations on global emissions and have been repeated over and over by the media.

According to a report by the Food and Agriculture Organisation of the United Nations from 2013 called Tackling Climate Change Through Livestock, the livestock sector  represents 14.5% of human-induced greenhouse gas emissions, with beef and cattle milk comprising over half of these emissions.

Let's stop here and put this figure into perspective. 14.5% of all global emissions is a lot but it's nowhere near the overblown figures that are sometimes quoted in the media, and is definitely lower than the two big contributors, which are the energy and transport sectors. Let's go back to that 14.5% figure. What is actually involved? What are the components of the livestock industry that contribute to these emissions?

I'm going to hit you with a lot of figures here so I apologise in advance but it is necessary to understand where these emissions are coming from.

A full 45% of these emissions, almost half, is due to what the report calls feed production and processing. What does that mean? If you grew up in the west of Ireland like I did, you probably think that cows just feed on grass that grows naturally on fields. How could this account for almost half of emissions, there's no fossil fuel inputs here. The reason is because most cows in the world are not allowed to roam large fields and graze naturally on grass, the food they evolved to be experts in digesting. Instead, they are kept in what's called factory farms or feedlots - essentially they are kept in confined spaces and fed crops like wheat and corn. It's worth saying that these are not the foods that cows evolved to eat and it can make them very sick. But it's also highly inefficient because you need other land to grow those crops, which is grown with fertilizers that release nitrous oxide. The crops are harvested with large machinery and transported to cattle farms. What's more, when you plow land to grow cops, that releases carbon that's been stored in the soil. Soil is a huge carbon sink, just like trees - this is something I will talk about more later in the episode. That is a big part of where these carbon emissions are coming from. We are releasing emissions to grow food to feed cows that they don't even naturally eat.

What's more, in some parts of the world like Brazil, they are chopping down rainforest to convert the land to cattle farms, which is obviously a terrible idea in terms of emissions and habitat.

A further 10 percent of emissions relating to livestock is due to what's referred to as manure storage and processing. Yes, I'm really talking about this. You see, when lots of cows are kept in a confined space they produce a lot of waste. This results in literal rivers of manure that has to be stored and then safely disposed of. This releases methane and nitrous oxide, two potent greenhouse gas emissions. It can also have terrible local environmental and public health impacts. Manure releases gases that are harmful to human health. If this manure gets into rivers through illegal dumping or because of flooding, it essentially poisons the river's ecosystem, killing fish and spreading pathogens.

About another 9% of emissions comes from processing milk and meat and transportation of the products.

The final part of this emissions puzzle is a whopping 39% of the sectors greenhouse gas emissions from what scientists call "enteric fermentation from ruminants", or what you probably know as cow farts, which release methane. They are actually cow burps, not farts by the way. You may not think that is an important distinction but while we're on the topic, we might as well get this right. 

Methane is a huge topic so I want to address this right now. The media has really taken hold of this point about methane emissions from livestock and blown it up to seem like it is one of the major causes of climate change. You've probably heard that methane causes 20 times more warming than carbon dioxide. This is technically true on the molecular level but methane is far less abundant than CO2 and it only stays in the atmosphere for about 10 years. Compare this to carbon dioxide, which can hang around for a thousand years. It is estimated that methane is responsible for about 20% of the effects of climate change. Make no mistake, carbon dioxide is very much the major driver of climate change, not methane.

Cows and other ruminants naturally emit methane as part of their digestive process. They've been doing this for thousands of years. And they are not the only sources of methane. Methane occurs naturally in the atmosphere, emitted from non-human sources wild animals, wetlands, volcanoes and forest fires. These natural sources account for 40% of all the methane in the atmosphere, with human sources, also called Anthropogenic sources, accounting for 60%.

The Global Methane Initiative estimates that enteric fermentation is responsible for 27% of anthropogenic methane sources. Fossil fuel extraction and processing is responsible for 33% of anthropenic emissions, with the remainder being from municipal solid waste, wastewater, rice cultivation and other minor sources.

To complicate things further, scientists admit that calculating sources of methane is incredibly difficult and the figures are always under review. A study was released in early 2020 that suggest that human-caused emissions of methane from from the extraction and use of fossil fuels may have been severely underestimated in previous studies. The implication is that methane emissions from fossil fuels are 25-40% higher than earlier estimates suggest.

So what we're saying is that methane emitted from livestock is maybe 27% of the 60% of methane that is caused by humans, which itself only accounts for 20% of the effects of climate change.

When you consider it that way, the role of cow burps in our climate emergency appears incredibly minor. But let's move onto the main crux of the argument. How can we manage livestock better?

Mimicking Nature

So far you might be thinking that I'm not doing a very good job in defending cows and that all this sounds awful. And it is awful. You can see the wisdom in telling people just to eat less beef, because if there is less of this going on in the world, that can only be a good thing, right?
But the reason that livestock creates all of these problems is because we have taken them out of their natural environment and ecosystem and put them into these intensive feed lot farms. All of the greenhouse gas emissions that I've talked about here are by-products of this method of intensively growing cattle for milk and meat. With the exception of methane, they aren't caused inherently by cows.

So is it possible to have cows without all of these negative effects? Is it possible even to make use of cows to have a positive effect on the environment?

To answer this, let's take a step back and consider cows and livestock for what they are - they are animals who evolved within a particular environment and fulfil a particular niche. A DNA study from 2012 indicates that all modern European cattle are descended form as little as 80 wild ox, or auruchs, that were domesticated in the fertile crescent 10,500 years ago. Wild Ox are now extinct but we can look to their close relatives like bison and buffalo, or even to other large ruminants like deer, zebras and wildebeest. All these species form large herds comprised of hundreds, thousands, sometimes even millions of individuals. If these herds stayed in one place for long they would quickly consume all of the vegetation and leave a barren landscape behind. And This is where the balance of nature comes in.

These herd animals are always at risk of being preyed upon by big cats and wolves. In fact that's why they form herds in the first place - you stand a much better chance of escaping a pack of lions if you are with a thousand others than if you are alone. So a predator shows up and the entire herd moves away to find somewhere more peaceful to eat. We are all familiar with seeing this phenomenon on nature programs on TV. What many people don't appreciate is the important connection between this behaviour and the health of the grasslands ecosystem. These grass eating animals prune the mature vegetation, agitate the soil with their hooves and leave lots of manure on the ground, and then they move on. Now that the grassland has a chance to recover, the manure fertilizes the soil, giving it nutrients to grow fresh vegetation. Until another herd shows up and the whole cycle begins again. This process locks away carbon in the soil, potentially for thousands of years and contributes to soil health and ecosystem diversity.
The amazing thing is that if there are too many herd animals without predators, they will overgraze and harm the ecosystem, even causing it to become a desert, which happens in equatorial parts of the world when land is overgrazed by livestock. When this happens, or the soil is tilled for crops, it releases carbon that has been stored in soil. On the other hand, if there are too few animals, then the grass grows and grows until it dies and dries out, smothering the soil and preventing fresh growth from coming up, harming the ecosystem in another way. The vegetation, ruminants and predators all evolved together and so if you mess with one part of that balance, you harm the landscape and potentially release stored carbon.

But what does this have to do with domesticated cattle? Well, it comes back to my point that many of the problems associated with the livestock industry are to do with how we as humans mismanage these poor creatures. There are some people, however, looking beyond the status quo and arguing that cows may hold the key to restoring lost ecosystems and sequestering huge amounts of carbon.

The first example I want to look at comes from a wildlife biologist called Allan Savory. He gave a fascinating Ted Talk back in 2013 where he made the case that what he calls Holistic Planned Grazing of livestock can heal land that has been desertified and restore it to a lush, grassland ecosystem, which sequesters carbon in the soil. Holistic Planned Grazing involves managing livestock to mimic the natural predator-prey relationship that I discussed earlier. The basic principle is that instead of allowing a herd of cattle to graze continuously on your entire plot of land, you sub-divide the farm up into smaller fields. The animals are then allowed to intensively graze a portion of the farm for a period of time before being moved onto the next portion. This allows the soil and vegetation to recover, absorbing carbon as it does.

Savory even argues that if you did this on a large enough scale throughout the world, you could bring atmospheric carbon down to pre-industrial levels. Now, this claim, as far as I can tell, is unsubstantiated. Other experts think that the actual potential for sequestration is much lower, although still significant.

That being said, on the face of it, his methods do seem to create a remarkable transformation of landscapes. If you watch the Ted talk, he shares a number of examples of barren, desertified landscapes that have been transformed into lush green, functioning grasslands. The website for his organisation, the Savory Institute, says that these methods are currently being used on 13 million hectares of land around the world. And there are lots of testimonials from farmers who have had great success in using the Holistic Planned Grazing method.

It's a very bold vision and one that has received both praise and criticism. The Ted Talk has received almost 12 million views between youtube and the Ted website, so this is a fringe idea that has come into the mainstream. Within the scientific community there is undoubtedly much scepticism. But there is also more and more hard evidence coming forward to support the idea.

A particular study from 2018 by Stanley et al from Michigan State University and the Union of Concerned Scientists, conducted a life cycle assessment comparing the greenhouse gas emissions from a typical feedlot cattle farm and a farm that employed a very similar concept to Alan Savory's Holistic Planned Grazing called Adaptive Multi-Paddock Grazing. Sometimes people also call this Rotational Grazing. There are multiple names for essentially the same concept. This is a life cycle assessment, which means it looks at all the emissions related to the cows, including their methane production, farm operations, feed and transportation. The way the results of the study are presented is slightly cryptic for non-scientists but I'll try to explain it. Basically, the assessment measured the kilograms of carbon dioxide emissions equivalent per kilogram of carcass weight. So carbon dioxide equivalent mean all greenhouse gases, so including methane, but expressed as if it is carbon dioxide. This is something scientists do to make it simpler to talk about all emissions at once. And the carcass weight is the weight of the animal after its been slaughtered. It seems a bit strange but that appears to be the standard way of expressing these assessments.

What's important is the result. So, 1 kilogram of the typical feedlot beef resulted in 6.12 kilos of greenhouse gas emissions. Whereas the beef from the Adaptive Multi-Paddock farm resulted in minus 6.65 kilos of greenhouse gas emissions. So the way the cattle were managed was able to sequester enough carbon and methane within the soil not only to make the meat carbon neutral, but actually carbon positive. You can imagine that at a large scale, over thousands and thousands of animals, this really starts to add up and make a significant contribution. The authors of this paper point to two other academic studies, both from 2016, that showed even greater sequestration levels on farms in the US. So the scientific evidence for this is definitely growing.

Let's talk briefly again about methane. I said earlier that cows do emit methane but it's probably not nearly as big a deal as we have been led to believe. What's more, methane can actually be absorbed into soils when the land is managed properly. So by using these methods, we can create a kind of closed loop where, yes methane is emitted into the atmosphere but eventually it is brought back down to earth and consumed by bacteria in soil.

As a quick summary, by raising animals on grasslands in a way that mimics nature, we remove the need to grow crops to feed them, which comprising almost half of livestock's emissions. We have done away with the problems surrounding manure storage and processing because the manure just stays on the land and helps to fertilize the soil. What remains is transport related emissions and methane from enteric fermentation. But these can be offset entirely by the ability of the soil to sequester greenhouse gases. Plus the land is absorbing more carbon, making the whole enterprise carbon positive. So there you go, that is why cows are not necessarily evil.

I've focused on carbon emissions because I think that is the most compelling aspect of this story. But it's not the only benefit. These livestock management methods I've been talking about essentially recreate a natural grassland ecosystem. And with that they greatly improve biodiversity of plant and animal life, and improve soil fertility. I've spoken before about the need for climate solutions that are multi-functional - that have multiple benefits. And this could be on of them. Not only can we produce high quality food but also sequester carbon, improve local biodiversity and improve soil fertility.

This is particularly important on land that has been depleted, degraded and desertified through years of mismanagement. As Alan Savory says in his Ted Talk, this approach has the potential to reclaim land that has been lost to desertification across millions of hectares of land around the world, but particularly in developing nations.

To sum up where we have gotten to at this point, the way we currently go about raising animals for meat and dairy is contributing a small but significant amount to greenhouse gas emissions, climate change and local environmental degradation. However, the answer to this does not have to be to stop producing meat entirely. There are methods being pioneered that allow us to manage livestock in ways that can sequester carbon, rejuvenate soil fertility and improve biodiversity.