Animal-based meat production is a large contributor to climate change. Especially beef has a high a carbon footprint, measured in terms of kilogram CO2-equivalents per kilogram of meat. Switching from beef to chicken meat or insect meat lowers greenhouse gas emissions and hence decreases future climate change damages. But chicken meat has a much higher moral footprint (Saja, 2013) or welfare footprint (welfarefootprint.org) than beef. Chickens experience more intense suffering and more hours of suffering for one kilogram of meat, compared to beef cows.
This article shows that the increase in moral footprint when switching from beef to chicken meat or insect meat is likely to be worse than the decrease in carbon footprint. To compare these footprint changes, all the footprints are expressed in terms of the deathprint: the number of humans dying prematurely from climate change and the number of animals killed (slaughtered) in animal farming, for the production of one unit of meat.
The deathprint of climate change
A recent study (Bressler, 2021) estimated the net number of humans dying prematurely from temperature changes (especially heat waves) due to climate change, before the year 2100. An extra emission of 4000 ton CO2, emitted today, results in one extra human death due to climate change, in the business as usual scenario where everyone else does not take measures to reduce their emissions. Hence, 0,00000025 humans will be killed this century by emitting one extra kilogram of CO2.
I use this number of deaths for the calculations below, although this number is both an underestimation and overestimation of the total human deaths due to climate change. It is an underestimation, because it does not include deaths from e.g. famines, wars, infectious diseases, floods and other risks that are increased by climate change. On the other hand, this number is an overestimation in the sense that climate change adaptation measures and CO2 emission reduction measures are likely to be taken. If poor countries develop and become richer, people in those countries can take more adaptive measures such as installing air conditioning, which lowers the mortality rate from extreme temperatures. And if global CO2 emissions are reduced, the impact of an extra unit of CO2 emissions (i.e. the marginal mortality rate) reduces as well (due to the non-linear relationship between amount of CO2 in the atmosphere and climate damages).[i]
The deathprint of meat
The table below shows the amount of meat produced by one animal, and the carbon footprints of meat products. These footprints measure the greenhouse gas emissions, in terms of CO2-equivalents, including all life cycle emissions as well as land use change emissions from e.g. deforestation, for the production of one kilogram of meat. The values of beef, pork and chicken are taken from Pieper e.a. (2020), which applies to Germany. The carbon footprint of insect meat is assumed to be lower than the footprint of chicken meat but slightly higher than the footprint of plant-based protein. The chosen value is a preliminary estimate of cricket meat, taken from Blonk e.a. (2008). It requires roughly 10.000 crickets for the production of one kilogram of cricket protein powder.
|kg meat per animal consumed||animals killed per kg meat||kg CO2 per kg meat|
With these values, we can calculate the human and animal deathprints of meat, i.e. how many humans will die from climate change and how many animals are killed (slaughtered) for the production of one kilogram of meat. This animal deathprint of meat only includes the animals that will be consumed by humans, and excludes the animals used as feed (e.g. fish meal and insect meal given to farm animals). This means the displayed deathprint of meat is an underestimation of the total number of animals that are used for food.
|human deaths from climate change per kg meat||animals killed per kg meat||animals killed per human death|
Producing 108 tons of beef will cause one human death from climate change and an additional 360 cows killed. Producing 250 tons of chicken meat will cause one human death from climate change and almost 170.000 chickens killed.
Perhaps the value of a chicken life is less than a human life. How much chicken deaths is equivalent to one human death? The level of consciousness or intensity of experiences of chickens might be lower than the level of consciousness of (adult) humans, and this could mean a chicken is worth less than a human. It could be (but is far from obvious) that the level of consciousness correlates with the number of neurons in the brain. As a sensitivity analysis, I calculate a weighted deathprint, with neuron count as weights.
The table below shows the number of neurons for different animals (taken from Carl Shulman’s article). A human as 85 billion neurons. Hence, one human death corresponds with 85 billion human neuron deaths. One insect death corresponds with 200.000 neuron deaths.
|number of neurons in the brain||brain mass (gram)|
The next table shows the neuron weighted deaths (or neuron deaths) for different meat products. Even when weighting the value of a life by neuron count, one human death corresponds with 47.000 insect deaths.
|neuron weighted human deaths from climate change per kg meat||neuron weighted animals killed per kg meat||neuron weighted animals killed per neuron weighted human death|
The changes in deathprint from replacing meat products
What if a consumer switched from beef to chicken meat, or from chicken meat to insect meat? The next table shows how many humans are saved (by reducing climate change) and how many extra animals are killed when replacing one meat product with another.
|replacement||humans saved per kg meat replaced||extra animals killed per kg meat replaced||animals killed per human saved||animals killed per cow saved||animals killed per chicken saved|
|beef by chicken meat|
|beef by insect meat|
|chicken meat by insect meat|
If a consumer eats one kilogram of chicken meat instead of one kilogram of beef, five millionth of a human is saved from a premature death caused by climate change.[ii] But almost one extra animal is raised on a farm and killed (slaughtered). This means that switching from beef to chicken meat results in (net) more than 100.000 animals killed per human saved.
Note that the life of a present-day farm animal being slaughtered is most likely worse than the life of a future human who is prematurely killed by a heat wave due to climate change. Most people believe that most farm animals, especially chickens, have lives not worth living, with more negative than positive experiences, dominated by suffering over pleasure (Espinoza & Treich, 2021; Bruers, 2022). In contrast, climate change is unlikely to become so terrible that it causes future humans to have lives not worth living. This means the ‘100.000 animals to 1 human’ ratio is an underestimation of the overall disvalue (badness) of a present-day chicken suffering on a farm and being killed in a slaughterhouse relative to a future human dying from climate change. In this article, I neglect the disvalue of suffering during one’s life and focus only on the disvalue of death.
If you value a chicken life as less than one in 100.000 of a human life, in the sense that a human death is more than 100.000 times worse than a chicken death, you may believe that switching from beef to chicken meat is good overall, that the benefits for humans trump the costs for animals. Switching from beef to insect meat would be good overall if you value an insect life as less than one in a billion of a human life. If you value the life of a chicken as less than one in 200 of a cow’s life, switching from beef to chicken meat is net beneficial for the animals. If you value the life of an insect as less than one in 15.000 of a chicken life, switching from chicken meat to insect meat is net beneficial for the animals.
Is the life of a chicken worth less than 1 in 100.000 of a human life and less than 1 in 200 of a cow’s life? Let us see what happens if we weight the lives of humans and animals by the number of neurons.
|replacement||neuron weighted humans saved per kg meat replaced||neuron weighted animals killed per kg meat replaced||neuron weighted animals killed per neuron weighted human saved||neuron weighted animals killed per neuron weighted cow saved||neuron weighted animals killed per neuron weighted chicken saved|
|beef by chicken meat|
|beef by insect meat|
|chicken meat by insect meat|
I think it is unreasonable to value the life of a human more than 300 times the life of a chicken after weighting by neuron number. Such a valuation of a human life over a chicken life might correspond with for example a belief that the probability of a chicken being sentient (having a consciousness) is less than one in 300, which is unreasonably low. That means it is unreasonable to value a human life (not weighted by neuron count) as more than 100.000 higher than a chicken life.
Similarly, I think it is unreasonable to value a cow’s life more than 15 times a chicken life after weighting by neuron count (and hence 200 times higher without the neuron count weighting). Therefore, I think switching from beef to chicken meat is bad overall: the twofold reduction in the human deathprint from climate change (i.e. a decrease in carbon footprint with roughly 50%) is offset by a two hundredfold increase in the animal deathprint (i.e. a factor two hundred increase in the moral footprint).
The case against insect meat also becomes clear: switching from chicken meat to insect meat corresponds with more than 100 insect neurons killed per chicken neuron saved. Is a neuron weighted chicken life worth more than 100 neuron weighted insect lives? Perhaps you believe the probability of a chicken being sentient is more than hundred times higher than the probability of an insect being sentient? That would mean the probability of an insect being sentient is lower than one percent. But this seems unreasonable, in light of all currently available evidence of insect sentience (see for example the Welfare Range Table from the Moral Weight Project).
Switching from beef to chicken meat reduces climate change but increases animal suffering. The increase in animal suffering when eating chicken instead of beef is most likely worse than the increase in climate change when eating beef instead of chicken, making the switch from beef to chicken bad overall. Similarly, the switch from beef or chicken meat to insect meat might be bad overall, because much more animals (insects) are killed for an amount of insect meat compared to an amount of beef or chicken meat.
Advice for consumers
- Prioritize a reduction of chicken meat consumption.
- Avoid insect meat products.
- Do not replace red meat (beef and pork) by chicken meat. Replace beef and other animal-based meats by plant-based meats.
Advice for policymakers
- Introduce a meat tax that includes both the external costs of climate change and animal suffering, and make sure that the tax rate for chicken meat is at least as high as the tax rate for beef.
- Stop subsidizing research on insect meat.
- Increase subsidies for research and development of animal-free meat such as plant-based and cell-based meat.
Blonk, H., Kool, A., Luske, B. (2008). Milieueffecten van Nederlandse consumptie van eiwitrijke producten (in Dutch, Environmental effects of Dutch consumption of protein-rich products). BMA/VROM, Gouda.
Bressler, R. D. (2021). The mortality cost of carbon. Nature communications, 12(1), 1-12.
Bruers, S. (2022). The animal welfare cost of meat: evidence from a survey of hypothetical scenarios among Belgian consumers. Journal of Environmental Economics and Policy, 1-18.
Espinosa, R., & Treich, N. (2021). Animal welfare: Antispeciesism, veganism and a “life worth living”. Social Choice and Welfare, 56(3), 531-548.
Pieper, M., Michalke, A., & Gaugler, T. (2020). Calculation of external climate costs for food highlights inadequate pricing of animal products. Nature communications, 11(1), 1-13.
Saja, K. (2013). The moral footprint of animal products. Agriculture and Human Values, 30(2), 193-202.
[i] Furthermore, from a population ethical point of view, it is difficult to include the number of humans dying from climate change after the year 2100, because these humans are not yet born, and their existence depends on whether or not we take emission reduction measures. In the world where we take emission reduction measures, other people will be born compared to the world where we do not take those measures. If we emit an extra amount of CO2, there will be an extra increase in climate change, and a person in the far future could die from this extra climate change. But if we did not emit that extra CO2 and hence we did not cause that climate change, that person will not exist (other people may be born instead). It is not obvious to say that we saved a person when preventing the killing of that person would mean preventing the very existence of that person. I prevented the killings and premature deaths of all my unborn children who will never exist, but that does not mean I saved all those non-existing children.
[ii] I’m excluding market shift effects due to price changes. I assume the switch of 1 kg of beef to 1 kg of chicken meat corresponds with a decrease in total beef production by 1 kg and an increase in total chicken meat production by 1 kg.