What are the trade-offs between animal welfare and the environmental impact of meat?

Eating meat with a lower carbon footprint often means killing more animals and treating them more poorly.

An increasing number of people would describe their dietary habits as “flexitarian” or “reducitarian.” These are people who still eat meat and dairy but are trying to reduce their consumption, often for environmental or ethical reasons. In the UK, there are more flexitarians than vegans, vegetarians, and pescetarians (who only eat fish) combined.

These ethically-conscious consumers still have a choice to make: what types of meat should they eat to reduce their environmental impact and reduce animal welfare costs?

It’s tempting to assume that what’s good for the planet is also good for the animal, but unfortunately, this is not the case. These two goals are often in conflict. What’s better for animal welfare is often worse for the environment, and vice versa. This is true across different types of livestock (for example, beef versus chicken) and across different ways of raising a specific animal (caged versus free-range hens).

This trade-off is easily missed. How consumers navigate this dilemma will depend on their values and priorities, including other things such as cost, taste, and their relationship with farmers and communities.

In this article, I’ll present some of the research on the trade-offs between environmental protection and animal welfare so that you can decide what you want to do when faced with this trade-off.

Swapping beef burgers for chicken burgers lowers your environmental footprint but is worse for animal welfare

Swap a beef burger for a chicken one, and you’ll cut the carbon footprint of your dinner by around 80%.1 The problem, however, is that you’ll need to kill 200 times as many chickens as cows to get the same amount of meat. An average chicken might produce around 1.7 kilograms of meat, while a cow produces around 360 kilograms.

This is true for other types of livestock, too. In the chart below, I’ve shown each type of meat’s carbon footprint on the right and the number of animals killed to produce one tonne on the left. You can see the trade-off. Bigger animals — cows, pigs, and lambs — emit more greenhouse gases but produce much more meat per animal. Chicken and fish might have a low carbon footprint but are killed in much higher numbers.

The consequence is that many more smaller animals — chickens and fish — are slaughtered. As my colleague, Max Roser shows in another article, every day 200 million chickens and hundreds of millions of fish are killed, compared to several million pigs and sheep, and about 900,000 cows daily.

Butterfly chart showing the number of animals killed to produce one tonne of meat vs. the greenhouse gas emissions of producing that meat. They are inversely correlated.

To give these figures some context, the average person in the European Union consumes around 80 kilograms of meat per year. If all of this came from chicken meat, about 40 chickens would have to be killed per person.2 From beef, it would be less than one-sixth of a cow. That’s one cow every 6 or 7 years.

But it’s not just the number of lives that matters. The life of an average chicken is likely much worse than a cow's. Nearly all of the world’s chickens are factory-farmed. I’ve written about the painful conditions that many chickens experience throughout their lives. While it is certainly the case that some cattle will also experience poor standards of care, they’re more likely, on average, to have higher levels of welfare.3

It is difficult to navigate this tradeoff. Swapping beef for chicken and fish will reduce your environmental footprint but at the cost of more animals living more painful lives.

Poorer welfare standards tend to have a lower carbon and land footprint

Some flexitarians will prioritize the environment and choose chicken. Others will favour animal welfare and go for beef. Some will try to balance both and go for pork.

The choice is then a simple one, right? Surely, organic pork is better for the animal and the environment. Or the free-range chickens are happy, healthy, and have the lowest impact.

Unfortunately not. These trade-offs also exist within any given type of meat.


Pack chickens in tiny cages, and you’ll need less land. Stop them from moving around, and they’ll “waste” less energy. Give them growth hormones, and they’ll gain weight much faster. This is better for the climate because it means they need less feed to reach their market weight, saving fertilizer, land, water and other resources, and will often lead to less manure, which is another source of greenhouse gas emissions. But, of course, all of these choices will make animal lives more miserable.

In a previous article, I examined how chicken breeds have changed over the last 50 years. “Fast-growing strains” of chicken — which gain weight more quickly — have become increasingly popular.4 As is shown in the diagram below, after 56 days, the typical broiler chicken in 2005 was more than four times heavier than the average chicken in the 1950s. This gives modern chickens various health problems but is ultimately better for the climate because of the feed efficiency reasons I explained above.

Image of chickens at different life stages, in the 1950s, 1970s and 2005. Chickens in 2005 are much bigger than those in the 1970s and 1950s.

A 2019 review by the European Commission — “Impact of animal breeding on GHG emissions and farm economics” — notes that the carbon footprint of chicken production has been falling in recent decades, almost entirely due to improvements in the rate at which chickens grow. It notes that “further improved growth rate has by far the highest potential to reduce the GHG emissions of broiler production.”

The trade-off for animal welfare is clear. The report suggests that one of the barriers to further reductions in greenhouse gas emissions is animal welfare concerns among consumers:

“During recent years, there has been a growing market demand for slow-growing broilers, which have perceived higher welfare, as an alternative to the fast-growing, energy-efficient broilers. [...] Growing such slow-growing lines would result in a substantial increase in GHG emissions and other environmental burdens due to increased feed consumption of the birds over the longer production cycle.”


What’s true of chickens is also true of eggs. Caged hens require fewer resources than free-range ones and, therefore, have a lower carbon footprint.

A study comparing caged, free-range, and organic hens in the UK found that the caged hens produced more eggs and needed less feed. This reduced their carbon footprint by around 16% per kilogram of egg.5 Studies in the Netherlands and the Czech Republic found the same: battery or caged hens had the lowest carbon footprint.6


The same principles apply to cows. More efficient agriculture tends to reduce environmental impacts, but it also comes at the cost of worse animal welfare.

Grass-fed beef tends to have a higher carbon footprint than grain-fed. A study by Daniel Blaustein-Rejto and colleagues found that the emissions from grass-fed beef were around 20% higher than from grain-fed cows.7 Exclusively grass-fed beef also uses more land, so the “carbon opportunity costs” — how much carbon could be sequestered if you weren’t using that land for farming — are higher. When Daniel Blaustein-Rejto and colleagues included these “missed” costs, the carbon footprint of grass-fed beef was 42% higher than grain-fed.

Most grain-fed cows spend at least part of their lives outdoors, where they are fed on grass, hay, and other forage. What’s different is that they are transitioned to a grain-fed diet towards the end of their lives. In that sense, “grain-finished” is a more accurate term. Grain-fed cows can experience discomfort in a few ways. First, they are often transported from the field to a feedlot, which can have a physical and mental toll.8 The noise and vibrations of the journey can be stressful, conditions can be cramped, and they can be deprived of feed and water. A poorly managed transition from grass to grains can cause digestive issues and discomfort. There are ways to reduce some of these negative impacts, but the overall welfare of grain-fed cows is probably lower than grass-fed.

Grain-fed cows tend to gain weight more quickly, which means they reach their “optimal” weight sooner and are bigger at the end of their lives. They convert more feed into meat compared to grass-fed cows, which is why the carbon footprint of grain-fed beef tends to be lower. Several studies have reported similar results.9


It’s a similar pattern for pigs.

In a paper published in Nature Food, Harriet Bartlett and colleagues studied the environmental impacts, welfare costs, and antibiotic use in 74 pig “breed-to-finishing systems” in the UK and 17 in Brazil.10 This is the stage of production where pigs are fed to reach market weight.

Overall, they found pretty large trade-offs in most of these systems. Farms with better animal welfare tended to emit more carbon and use more land. You can see this relationship in the chart below, which compares the emissions per kilogram of meat to the welfare cost.

Here, a higher welfare number — on the horizontal axis — is worse for the animal. Values further to the right represent a higher welfare cost. Negative figures, further on the left, are considered a welfare “benefit” — the quality of life is high enough that living longer is considered to add to its welfare. Welfare was scored based on standard methods that consider length and quality of life, and 30 different indicators of health and well-being.11

Overall, systems with higher greenhouse gas emissions tend to be on the left-hand side, meaning they benefit the pigs. Farms with lower emissions tend to be worse. This is also true for land use: poorly treated animals need less land.

Click to open interactive version

The study also found that the typical consumer labels on food products did not guarantee good outcomes. The chart below shows the greenhouse gas emissions and welfare costs of different pig farms, grouped by typical assurance labels on pork and bacon packs, such as “Red Tractor” certified or “Organic”.

There is a large overlap between all of these systems. Free-range systems, for example, have better animal welfare than systems with no label, but there are some farms where the pigs suffer welfare costs, not benefits. Some “RSPCA” farms also have welfare costs. Buying one of these labeled products might improve the odds of getting a well-treated pig, but it doesn’t guarantee it.

The median organic farm had higher carbon emissions, too. But again, there is some overlap between the different systems. This means that while these trade-offs are typical, they are not necessarily inevitable.

A dot plot showing the animal welfare and carbon footprint of pigs produced under different farming systems in the UK.

How to navigate animal welfare and environmental trade-offs

What can consumers do if they want to navigate these tradeoffs?

Of course, reducing overall meat consumption will shrink your environmental footprint and prevent animal suffering at the same time. I chose this path and maximized its benefits by eventually going vegan. But I also understand that the world is not going to go vegan overnight.

Consumers will still have to face some tradeoffs, and the options they choose will depend on their own rankings of values and priorities. That might mean switching to chicken to reduce your carbon footprint, sticking with beef because you think animal welfare is more important, or accepting 15% higher emissions for free-range eggs compared to caged ones.

On the producer side, some trade-offs in these impacts are unavoidable. You cannot get a high-yielding chicken without the use of fast-growing strains. But these trade-offs are not always inevitable: a small subset of farms have achieved both lower environmental impacts and good levels of animal care. The problem is that these examples are understudied. In fact, few studies have even identified them.

If we focus more research on how some systems balance these priorities, we might find insights that can be replicated elsewhere. The uncomfortable dilemma would not disappear completely, but it might ease this tension.


Many thanks to Edouard Mathieu, Pablo Rosado, and Max Roser for their valuable feedback and comments on this article and to Harriet Bartlett for the provision of study data.


  1. Beef emits around 5 times as much as chicken per kilogram.

  2. The 80 kilograms is measured as the “carcass weight”, a bit higher than the final meat supply.

    To adjust carcass weight to retail weight, I've applied the conversion factors from carcass weight to the weight of the consumed meat. These conversion factors are available from the OECD:

    That's 0.88 for chicken and 0.7 for beef.

  3. A study in the UK, for example, looked at real standards of care for beef cows, chickens, and pigs and measured them against key criteria of what constitutes a “good” life: comfort, pleasure, social interactions, interest, and healthy body types. They found that the chicken farms failed on most of the UK’s minimum standards; pig farms performed slightly better but still failed on many, and the beef farms passed the minimum standards, with the exception of the criteria to maintain a healthy body type.

  4. Havenstein, G. B., Ferket, P. R., Scheideler, S. E., & Larson, B. T. (1994). Growth, livability, and feed conversion of 1957 vs 1991 broilers when fed “typical” 1957 and 1991 broiler diets. Poultry Science.

  5. Leinonen, I., Williams, A. G., Wiseman, J., Guy, J., & Kyriazakis, I. (2012). Predicting the environmental impacts of chicken systems in the United Kingdom through a life cycle assessment: Egg production systems. Poultry Science.

  6. Guillaume, A., Hubatová-Vacková, A., & Kočí, V. (2022). Environmental impacts of egg production from a life cycle perspective. Agriculture, 12(3), 355.

    Van Asselt, E. D., Van Bussel, L. G. J., Van Horne, P., Van der Voet, H., Van der Heijden, G. W. A. M., & Van der Fels-Klerx, H. J. (2015). Assessing the sustainability of egg production systems in The Netherlands. Poultry Science.

  7. Blaustein-Rejto, D., Soltis, N., & Blomqvist, L. (2023). Carbon opportunity cost increases carbon footprint advantage of grain-finished beef. Plos one.

  8. Shields, S., & Orme-Evans, G. (2015). The impacts of climate change mitigation strategies on animal welfare. Animals, 5(2), 361-394.

  9. Clark, M., & Tilman, D. (2017). Comparative analysis of environmental impacts of agricultural production systems, agricultural input efficiency, and food choice. Environmental Research Letters, 12(6), 064016.

    Hayek, M. N., & Garrett, R. D. (2018). Nationwide shift to grass-fed beef requires larger cattle population. Environmental Research Letters.

  10. Bartlett, H., Zanella, M., Kaori, B., Sabei, L., Araujo, M. S., de Paula, T. M., ... & Balmford, A. (2024). Trade-offs in the externalities of pig production are not inevitable. Nature Food.

  11. Bartlett, H., Balmford, A., Holmes, M. A., & Wood, J. L. (2023). Advancing the quantitative characterization of farm animal welfare. Proceedings of the Royal Society B.

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    journal = {Our World in Data},
    year = {2024},
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