Cattle have numerous impacts on Earth’s climate and natural environments, despite misconceptions

Cattle populations have skyrocketed since humans first domesticated them roughly 10,000 years ago^[1]. And much of this growth happened relatively recently. From 1961 to 2022 – just a fraction of the time since domestication – cattle populations grew from 942 million to 1.5 billion globally – a roughly 63% increase.

And although humans have certainly benefited from this growth in many ways, such as improved food security^[2], there have also been a number of negative consequences for Earth’s climate and natural environments. Cattle are the number one source of greenhouse gas emissions among all livestock, for example, and are responsible for about 63% of the livestock sector’s total emissions.

The three main greenhouse gases emitted from cattle production – carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O)^[3] – contribute to global warming^[4], which has numerous impacts on human lives. Despite the evidence for this, misconceptions continue to circulate on social media. For example, as we showed in a recent review, viral claims have greatly underestimated or altogether misconstrued the climate consequences of cattle production.

In this article, we will explore what scientific evidence about the actual consequences of the cattle industry that, for most of us, is hidden from our daily lives. But it’s not all doom and gloom; in later sections we will also explore mitigation measures that scientists have proposed, like adding seaweed to cattle diets to reduce methane emissions.

There are roughly 1.5 billion cattle on Earth; farming them has climate consequences, despite misconceptions

Why are cattle a key part of discussions on Earth’s climate? To answer that, let’s start with a few numbers: there were an estimated 1.5 billion cattle on Earth in 2022 (Figure 1). With a global population of roughly 8 billion humans at that time, that’s about 1 cow or bull for every 5 people.

Growing these cattle requires extensive land and resources – which can degrade the natural environment^[5] – and emits greenhouse gases emissions both from farming operations and biologically by cattle themselves^[3]. For example, the U.S. EPA reports that cattle produce roughly 104 million metric tons of methane – a potent greenhouse gas – globally each year.

Whether or not you consume meat, the numbers above and their impacts on Earth might surprise you. However, it’s not just the number of cattle that may come as a shock, but also where they reside – hint, it’s not all grassy pastures.

 

When we hear the word ‘cow’ or ‘cattle’ it’s easy to imagine farm animals freely roaming on healthy green pastures. Afterall, this is what many of us see in advertisements and – for those who live in urban areas – the small exposure we might get when driving past farms in rural areas. Viral online misinformation has also misled people by showing pictures of cows on grassy pastures to suggest that cows mostly live in natural areas (like pastures) and can’t negatively impact Earth’s climate. But in many cases, this is far from the reality of how cattle are produced and greatly underestimates how cattle operations impact the natural world.

In the United States (U.S.), for example, it’s estimated that the majority of cattle are raised in factory farms. It’s been estimated that in 2022, roughly 75% of cattle – 66 million of them – were factory farmed in the U.S. While there’s no single definition that describes ‘factory farms’, these farms generally include animal feeding operations (AFOs) which, according to the U.S. Environmental Protection Agency (U.S. EPA), involve cattle being confined at least part time (45 days or more per year) on lots or facilities that do not sustain crops, vegetation, forage growth, or post-harvest residues. Instead, feedlot operations (Figure 2) rely on high-input forage (like corn) grown elsewhere. These operations are far from being ‘healthy green pastures’.

In reality, cattle production methods widely vary, both when comparing farming methods of the same type (e.g., pasture to pasture) and different types (e.g., pasture to factory farms)^[3]. For this reason, broadly comparing the impacts of these methods is not as straightforward as it may seem. Fortunately, climate scientists have analyzed different methods and summarized some of the key differences in the climate and environmental impacts.

For example, in a 2015 peer-reviewed paper published in Environmental Research Letters, climate scientists analyzed the climate impacts of beef by looking at different timescales (out to 1000 years from present) and production methods.

As the authors of that paper explain:

“It is concluded that certain forms of pastured beef production have substantially lower climate impact than feedlot systems. However, pastured systems that require significant synthetic fertilization, inputs from supplemental feed, or deforestation to create pasture, have substantially greater climate impact at all time scales than the feedlot and dairy-associated systems analyzed.”^[3]

In other words, some pastured cattle operations have a much lower climate impact than feedlot systems (e.g., factory farms), but not all of them. But why is this important? In recent years, misinformation has spread online that can easily mislead people from understanding how something seemingly natural and benign like cattle can affect Earth’s climate.

Misinformation about cattle oversimplifies the realities of farming and often relies on a fallacy that ‘nature is always good’

In recent years, memes about cattle have gone viral on social media which often use cherry-picked images of cattle in natural settings (like a green pasture) to claim that ‘cattle can’t impact Earth’. This is incorrect in two ways: it implies that cattle on pastures do not have any climate or environmental impact (which is false) and that cattle are mostly on pastures (also false).

As we explained in the last section, there are places like the U.S. where tens of millions of animals are raised in factory farms, not pastures. So the assumption that all cattle live in pastures excludes a major portion of cattle farming operations. Secondly, studies have shown that although some pasture operations have a lower climate impact than feedlot systems, some are actually worse^[3].

Underlying this claim that ‘pastures are harmless’ is a suggestion that natural things are always good. This is called the ‘appeal to nature’ fallacy. However, there are countless examples that demonstrate why it is false to claim that all things in nature are good.

An obvious example would be a poisonous plant – something that is natural, but also clearly dangerous. Likewise, a massive tsunami – something which is natural – can devastate coastal cities, but would be considered ‘good’ under this faulty logic. So even if cattle grazing on a pasture looks ‘natural and good’, that does not mean it’s harmless.

The actual scientific evidence is more complex – but the overarching conclusion is clear: cattle farming impacts Earth’s climate and natural environments. We’ll explain how below.

Cattle production impacts Earth’s climate through emission of greenhouse gases

Cattle farming impacts the natural world in two main ways: direct impacts to natural environments through things like deforestation and land degradation^[6], and broader impacts to Earth’s climate through greenhouse gas emissions (e.g., CO₂, CH₄, and N₂O) both from cattle themselves and farming operations^[3].

Cattle produce a significant amount of methane, for example, due to their ‘ruminant digestive systems’, which ferment the foods they eat and produce methane^[3]which is expelled primarily through belching (burping). Although this is a natural process, there are over 1.5 billion cattle which, together, release over 100 million metric tons of methane gas per year. For comparison, this is 80% of the estimated total amount of methane emitted by oil (petroleum), natural gas, coal, and biofuels combined – or roughly 18% of annual global methane emissions from both human activity and natural sources (Figure 3).

Overall, methane is the second most important greenhouse gas contributor to climate change^[8] and 60% of methane emissions come from human activity. Cattle production also produces N₂O along several steps of the lifecycle from animal to food product; it can be released from agricultural soils, from the production of feed for cattle, and through decomposition of manure^[3]. And lastly, CO₂ is produced through the various energy inputs required in farming cattle^[3]and later to produce resulting food products^[9].

These greenhouse gases warm Earth through radiative forcing^[4,10,11] – a process which essentially traps some of the outgoing infrared radiation (heat) that would otherwise escape out to space, as we’ve detailed in a past review.

There are different ways of determining how these emissions impact Earth’s climate. Because each gas has a different lifespan in Earth’s atmosphere, emissions are often converted into what’s called ‘CO₂-equivalent’. This method allows for gases other than CO₂ to be standardized to determine their global warming potential.

Using this method, Our World in Data analyzed data from a 2018 peer-reviewed paper published in Science and found that each kilogram of beef (food product) produced emits roughly 99.5 kilograms of CO₂-equivalent (Figure 4). This is nearly a 1:100 ratio of food produced to CO₂-equivalent emitted. For comparison, producing 1 kilogram of poultry meat (like chicken) emits 9.9 kilograms of CO₂-equivalent – roughly 10 times less than beef.

Although CO₂-equivalent is a useful metric to compare emissions, some climate scientists argue that determining the warming associated with each gas allows for a more robust assessment of the climate damage they can do^[3]. This is because each of these gases have different lifespans and effects in Earth’s atmosphere over different timescales.

Methane, for example, is short-lived in Earth’s atmosphere, but is a very potent greenhouse gas. In Earth’s atmosphere, methane has an average lifespan of 12 years, while CO₂ can exist for centuries. It’s easy to mistakenly assume this means that methane is not an issue for global warming – however, that would ignore the fact that methane emissions are ongoing and its

greenhouse effects are stronger than CO₂ in the short term^[4]. As explained by the U.S. EPA:

 

“Though CO2 is more abundant and stays in our atmosphere longer, methane is more damaging. In fact, as a greenhouse gas, methane is 28-times more powerful than CO2 on a 100-year timescale and 80-times more powerful over 20 years.”

 

With these differences in mind, climate researchers projected 1000 years of future warming by looking at contributions of individual greenhouse gases (instead of comparing CO₂-equivalents) under different cattle production methods and emissions scenarios. They used scenarios to compare production methods: one is a pastured model (‘Brazilian pasture without deforestation’) meant to approximate a ‘purely grass fed’ scenario, and the other is a feedlot model (‘midwest feedlot’) – a crop intensive scenario with high use of synthetic fertilizers and more reliance on machinery. As shown in Figure 5, they then modeled the emissions and associated warming of these methods under different conditions: perpetual consumption of beef and gradual phase-out of consumption (Figure 5). As the researchers explain:

 

“The two phase-out cases illustrate that the warming due to CH₄ and N₂O is reversible, whereas the warming due to CO₂ is not (at least not on any time scale of relevance to human societies).”^[3]

 

While there are obvious uncertainties in projecting temperatures impacts out this far into the future, the models reveal very important aspects of emissions and warming from cattle production. For example, Figure 5 shows the much stronger warming effect of methane in the short term, but the longevity and influence of CO₂ over the long term.

This is clear in the ‘phase-out’ graphs, as the line showing warming due to CO₂ steadily rises, while methane increases abruptly, then quickly drops after beef consumption is phased out. (See the steep ‘hill’ shape followed by a long run out in Figure 5).

This is good news in the sense that some warming can be reversed with decreased meat consumption. However, the graphs showing a scenario where beef consumption continues at a steady rate demonstrate that methane – although being a short-lived greenhouse gas – continues to warm Earth if it continues being emitted, as shown by the steady rise of warming in the bottom graphs of Figure 5.

 

However, the reversibility of related global warming in these scenarios depends on a gradual decline in beef consumption. This is a big assumption, given that human populations on Earth are currently growing, and as these researchers explain:

 

“Barring major cultural changes, or policy actions designed to discourage meat consumption, it is likely that beef consumption will rise in the future, as a result of growing population and the increase in per capita consumption typically associated with rising affluence^[12,13]”

What happens if both population and consumption continue to grow? In the 2015 Environmental Research Letters paper, researchers explain that:

“All methods of beef production have severe climate impacts when extrapolated to peak production rates corresponding roughly to the current US per capita rate being consumed by a population of 10 billion.”

 

However, long-term climate impacts are not the only concern when it comes to cattle production. There are also direct environmental impacts, which we will discuss below.

Cattle production directly impacts natural environments through things like deforestation and land degradation

Although there is wide variability in environmental impacts of different cattle production methods^[9], studies have shown that beef has the largest environmental impact of all meat products.

For example, a 2010 paper published in Livestock Science looked at 16 peer-reviewed papers on the environmental impacts of production of different animal products. The papers they reviewed included life-cycle analyses – a way of measuring impacts over a product’s entire lifecycle (i.e., from ‘cradle to grave’) – for production of pork, chicken, beef, milk, and eggs. After reviewing these papers, the researchers concluded that 1 kilogram (kg) of beef had the highest land use and energy requirements, “followed by production of 1 kg of pork, chicken, eggs, and milk”^[9] (Figures 6 and 7).

Cattle farming can require extensive land to graze and live on, and in some places this land is obtained through deforestation. As explained in a 2024 Nature Sustainability paper: “Livestock rearing on land is one of three key drivers behind land-use change and the single largest driver of habitat loss^[14]”^[15].

In Brazil – which is the world’s second largest beef producer (the U.S. being the first) – there are 2.5 million farmers operating on mostly pasture-based cattle production systems^[16]. As explained in a 2021 peer-reviewed paper published in Global Environmental Change:

“Deforestation of the Brazilian Amazon presents one of the greatest challenges to global conservation goals. More than 780 thousand square kilometers of forest has been lost in the last 30 years, causing nearly half of Brazil’s carbon emissions and the loss of 2,000 species ^[17],SEEG (2018), INPE (2020)]. Pasture expansion for cattle production is the main driver of deforestation and has been linked to 80% of clearing [Global Forest Atlas (2016)]”^[16]

Cattle production can also cause acidification (adding acidic compounds to the environment) and eutrophication (excess nutrient accumulation in bodies of water). Eutrophication occurs when an excess of nutrients enters water bodies, like rivers and lakes, which throws off the natural balance of those ecosystems, causing things like toxic algae blooms. Cattle farming can cause eutrophication when excess nitrogen (N) and phosphorus (P) is released from cattle urine and feces^[18] into nearby waterways. Cattle waste can also release ammonia (NH₃) and cause soil acidification which has adverse effects on plants and microorganisms.

So is there any hope to mitigate these problems? While there’s no simple answer given the complexity of this problem, scientists have proposed a number of mitigation measures ranging from dietary changes to more sustainable farming practices, which we will touch on below.

Scientists have proposed a number of solutions and mitigation measures; global adoption of these solutions has its challenges

Although Science Feedback is not here to advise the best course of action, below we will share some of the mitigation measures that climate scientists have proposed.

One of the tricky parts of this discussion is that diet – as opposed to other personal changes to help the planet, like modes of transport – directly affects our health. Given that diets are highly important both personally and culturally, a 100% global adoption of a certain diet is unrealistic and potentially even counterproductive to some people’s health goals.

However, there is clear evidence that certain diets are better than others for reducing climate impacts. A 2018 study reviewed 38,700 farms and 1,600 processors, packaging types, and retailers against five environmental indicators and found “Most strikingly, impacts of the lowest-impact animal products typically exceed those of vegetable substitutes, providing new evidence for the importance of dietary change.”^[19]

In a previous review, the climate and health teams at Science Feedback collaborated to investigate claims about how certain diets can improve your health and reduce climate impacts. The biggest takeaway was that adopting a flexitarian diet – one which is centered on consuming a higher proportion of plant-based foods than animal-based proteins – can improve your health and reduce greenhouse gas emissions.

A group called the EAT-Lancet Commission – 37 leading scientists from several different disciplines and 16 countries – collaborated to establish what they call the ‘Planetary Health Diet’, which the commission describes as a “plant-forward diet where whole grains, fruits, vegetables, nuts and legumes comprise a greater proportion of foods consumed”. They explain that while meat and dairy are still important parts of the diet, they make up a much smaller portion of the diet than the food categories listed above (Figure 8).

Luckily, for those who do wish to make dietary changes, there is major overlap between what is good for our health and the environment. As explained by Dr. Harry Aiking, Visiting Fellow at the Vrije Universiteit Amsterdam, who studies sustainable food production and consumption:

Aside from shifting human dietary trends, scientists have proposed other mitigation strategies, such as:

• Carbon sequestration (through decreasing rates of deforestation or replanting trees in deforested areas for example)^[2]
• Dietary adjustments for cattle (one study showed inclusion of seaweed in cows’ diets reduced their methane emissions by 67%^[21])
• Increasing productivity of livestock to reduce emission intensities (better livestock production practices could reduce emissions by 20 to 30%, according to the Food and Agriculture Organization of the United Nations [FAO])
• Better integrating livestock into the ‘circular bioeconomy’ by re-circulating wasted energy and materials back into the livestock production system (e.g., foods wasted by humans can be used for livestock)

But like the implementation of any solution at a large scale, the first step is ensuring people first understand the problem at hand. In the case of cattle production, this means spreading accurate information about the scale of climate challenges posed by this worldwide industry.

Conclusion

In conclusion, cattle production has one of the largest impacts on our climate and natural environments compared to all other livestock and food products in general. They can have direct impacts through deforestation and land degradation, but also long-term impacts to Earth’s climate through emission of greenhouse gases (carbon dioxide, methane, and nitrous oxide) which warm our planet. There are several challenges when tackling this problem.

Firstly, the problem itself is complex: the climate and environmental impacts of cattle have a number of factors – with large variations in impacts both between farming operations of the same types (pasture to pasture) and different types (pasture to factory farm). If everyone were aware of these issues, adopting solutions would perhaps be easier. However, misinformation continues to go viral online that misconstrues this reality, oversimplifying the problem using fallacies like ‘cows are natural, and therefore must cause no harm’. Those who fall for this misinformation can be misled to think that cattle are inconsequential and greatly underestimate their impact on Earth.

So, although climate scientists have established ways to mitigate climate challenges from cattle production, people are being misled – or misleading others – to believe that there is no problem at all. And those who don’t see a problem to be solved aren’t likely to seek or participate in solutions. There are already numerous mitigation measures that climate scientists have proposed, such as re-circulating wasted human food back into livestock production, human dietary adjustments (e.g., eating less meat), and more. But an important step to implementing solutions is ensuring that sure people have access to accurate information and scientific facts that allow them to understand the realities we face now and in our future.

References

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• 2 – Rojas-Downing et al. (2017) Climate change and livestock: Impacts, adaptation, and mitigation. Climate Risk Management.
• 3 – Pierrehumbert and Eshel (2015) Climate impact of beef: an analysis considering multiple time scales and production methods without use of global warming potentials. Environmental Research Letters.
• 4 – IPCC (2021). Sixth Assessment Report.
• 5 – Vries et al. (2015) Comparing environmental impacts of beef production systems: A review of life cycle assessments. Livestock Science.
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• 12 – Lambin and Meyfroidt (2011) Global land use change, economic globalization, and the looming land scarcity. Proceedings of the National Academy of Sciences (PNAS).
• 13 – Ausubel et al. (2012) Peak Farmland and the Prospect for Land Sparing. Population and Development Review.
• 14 – Díaz et al. (2019) Pervasive human-driven decline of life on Earth points to the need for transformative change. Science.
• 15 – Sahlin et al. (2024) An exploration of biodiversity limits to grazing ruminant milk and meat production. Nature Sustainability.
• 16 – Skidmore et al. (2021) Cattle ranchers and deforestation in the Brazilian Amazon: Production, location, and policies. Global Environmental Change.
• 17 – de Castro Solar et al. (2015) How pervasive is biotic homogenization in human-modified tropical forest landscapes?. Ecology Letters.
• 18 – Biagini and Lazzaroni (2018) Eutrophication risk arising from intensive dairy cattle rearing systems and assessment of the potential effect of mitigation strategies. Agriculture, Ecosystems & Environment.
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• 20 – Van Dooren et al. (2017) Proposing a Novel Index Reflecting Both Climate Impact and Nutritional Impact of Food Products. Ecological Economics.
• 21 – Roque et al. (2019) Inclusion of Asparagopsis armata in lactating dairy cows’ diet reduces enteric methane emission by over 50 percent. Journal of Cleaner Production.