Why is animal agriculture bad for the environment?

In 2006, the United Nations stated[1]: 

“The livestock sector emerges as one of the top two or three most significant contributors to the most serious environmental problems, at every scale from local to global. The findings of this report suggest that it should be a major policy focus when dealing with problems of land degradation, climate change and air pollution, water shortage and water pollution, and loss of biodiversity.”

And then four years later, they warned that a global shift towards a vegan diet is vital to save the world from hunger, fuel poverty and the worst impacts of climate change.[2]

So why exactly is animal farming bad for the environment?

Globally, 26 per cent of all the world’s ice-free land[3] surface is given to grazing animals and in total animal agriculture uses 83 per cent of all agricultural land[4], yet it provides less than 20 per cent of the calories consumed and less than 40 per cent of the protein[5] that is consumed.

In the UK, it is estimated that 85 per cent[6] of the land that is used for agriculture is just for animals, which is almost 50 per cent of the entire landmass of the UK.[7] And in the US, 41 per cent of the entire landmass is for animal farming compared to four per cent[8] which is used to grow plants directly for humans, with half of all agricultural land in the US being used specifically for beef production even though it makes up only three per cent of dietary calories.[9]

Animal farming is the leading cause of rainforest deforestation[10], the single largest driver of habitat loss[11] in general and agriculture, which also includes the farming of fish, is listed as being a threat to 24,000 of the 28,000 species[12] that are currently facing extinction.

And when it comes to the Amazon specifically, cow ranching is reportedly responsible for 80 per cent of rainforest loss in the Brazilian Amazon[13], with a recent investigation by the Bureau of Investigative Journalism showing that in 2019, fires in the Amazon were three times more common[14] in areas where there is cattle ranching. When it comes to soy, it is estimated that around 90 per cent of all of the soy that is produced in Brazil is used as animal feed, and globally 75 per cent of all the soy[15] that is produced is used for animal feed, with only 6 per cent of whole soybeans that are produced being used to produce plant-based products like tofu, soy milk and plant-based alternatives.

As for emissions, a University of Oxford report stated that even if the use of fossil fuel was ended immediately, the emissions produced by the agricultural sector[16] alone would make it impossible to limit warming to 1.5 degrees celsius and would even make it difficult to not hit two degrees. This means changes to our food system are essential if we want to avoid making the coral reefs disappear, creating more extreme heatwaves, water scarcities, droughts and food shortages for hundreds of millions more people, forcing them to be climate refugees. It is also vital if we want to avoid the continuing demise of the world’s biodiversity, increasing rates of dead zones and species extinction and the rising of sea levels causing the flooding of major cities such as Mumbai, Shanghai, Miami and New York and the potential for islands in the South Pacific ocean to disappear completely. 

Animal agriculture is responsible for producing between 14.5 and 18 per cent[17] of total greenhouse gas emissions (GHG), which makes it responsible for more emissions than the combined exhausts of all transport globally. The fishing method of bottom trawling alone is responsible for producing the same amount of emissions as the entire aviation industry.[18]

Switching to a plant-based diet can reduce agricultural emissions by as much as 73 per cent[19] in high-income nations and a study, published in the journal Science of The Total Environment, that analysed 313 different potential food systems[20] discovered that the highest GHG emissions were found in the food systems that included a high meat demand, especially if focused on ruminant meat and milk, and the lowest emissions were from the vegan diets.

But what about local animal products? Are they not more sustainable than buying plant foods from abroad? Well not according to the science, in fact when it comes to beef only around 0.5 per cent of the emissions[21] come from transportation and for lamb it is only two per cent, meaning that the issue of animal farming is the farming itself. Even with plant foods like avocados, only eight per cent of the total footprint comes from the travelling itself - indeed for most food products the transportation accounts for less than 10 per cent, with the higher transportation percentage simply being a reflection of the fact the food naturally produces lower amounts of greenhouse gases.

Furthermore, a report comparing greenhouse gas emissions[22] from the average diet across countries in the EU revealed that transportation was only responsible for six per cent of the total emissions related to diet, and when the results were broken down by food items, animal products were shown to be responsible for 83 per cent of emissions in the average EU diet, compared to only 17 per cent coming from plant-based foods.

In the US, the climate impacts of food choice were analysed[23] and food transport was shown to only account for five per cent of emissions in the average US household, which equals around 0.4 tons of CO2 equivalent. However, the study showed that substituting calories from red meat and dairy to plant-based alternatives for just one day a week would save 0.46 tons of CO2 equivalent, meaning that eating plant-based over red meat and dairy just one day a week would achieve the same result as having a diet with zero food miles.

The only way that buying local animal products could be more sustainable is if, to begin with, the farming of different foods was the same environmentally with the only difference being the miles the two foods had to travel. This is obviously not the case.

But isn’t regenerative beef good for the environment because grazing cattle can absorb carbon back into the soils? Not according to the meta-analyses that have been conducted on the matter. Grazed and Confused, a report by researchers based at the University of Oxford, states that although certain grazing managements can put carbon into the soil, at best this would only amount to 20-60 per cent of the emissions that the animals produce in the first place.[24]

After a few decades, the soil reaches soil carbon equilibrium as well, meaning the soil cannot sequester any more carbon. At which point none of the emissions from the animals would be offset. So farmers would either have to start grazing on more land, increasing the land used for animal farming, or stop the farming - meaning that grazing animals is not an effective short term or long term strategy for dealing with the problem either.

In the words of one of the lead researchers of Grazed and Confused, Dr Tara Garnett of the University of Oxford: “Grazing livestock are net contributors to the climate problem, as are all livestock. Rising animal production and consumption, whatever the farming system and animal type, is causing damaging greenhouse gas release and contributing to changes in land use.”

Even the lowest impact beef[25] is responsible for six times more greenhouse gases and a staggering thirty-six times more land than plant proteins such as peas.

Plus, there are more beneficial things we can do with the land, for example, research into the US food system found that reconfiguring cropland from animal feed to entirely human-edible crops, particularly ones that promote positive health outcomes such as fruits, vegetables and pulses, would feed an additional 350 million people compared[26] to what the same area of land produces in the current US food system. 

To put that into perspective, there are around 330 million people in the US, meaning another nation the size of the US could be fed with just the cropland used to currently feed animals there. Even if beef was just swapped for beans[27] in the diets of the US population, just under 700,000 square kilometres, which is the equivalent of 42 per cent of US cropland, would be freed up. Furthermore, in the UK just one-third of the cropland[28] currently used to grow animal feed could provide 62 million adults with their five servings of fruits and vegetables a day all year which, incidentally, is almost the entire UK population.

Plus, if the world shifted to a plant-based diet, we could feed every mouth on the planet and global farmland could also be reduced by more than 75 per cent[29], which, when put into perspective, is the equivalent size of China, Australia, the US and the entire European Union combined no longer being needed for agriculture. We could reforest and restore this land, bringing back lost habitats and reversing the decimation of the world’s biodiversity.

It is also estimated that by returning animal farms to natural vegetation we could remove the equivalent of 8.1 billion metric tonnes of carbon dioxide[30] from the atmosphere each year over the course of 100 years, which is about 15 per cent of the world’s total greenhouse gas emissions. So not only would a plant-based diet reduce total annual emissions by around 14 per cent but it would also allow us to sequester a further 15 per cent of total annual carbon emissions on top of that.

It would also mean reducing soil acidification and eutrophication, which is the process that creates algae blooms and dead zones, by 50 per cent.[31]

All of the issues related to animal farming have come from a planet with just under eight billion people on it. Within the next thirty years, our population is expected to increase to 10 billion. However, global trends, as they are now[32], are showing that animal product consumption is increasing regardless of the growing population. This means that by 2050, the overall food demand for animal-based foods will be 70 per cent higher and specifically ruminant meat being 88 per cent higher. For this, an additional 593 million hectares of land will be needed - the equivalent size of two Indias.

Something clearly has to change and quickly. How much more rainforest needs to be cut down or set on fire? Do major cities and entire islands need to be submerged underwater? How much more habitat needs to be destroyed and how many more species need to go extinct? How many more people need to suffer from food and water scarcity?

Don’t just take our word for it. The lead author of the largest and most comprehensive analysis ever conducted analysing the impact that food and agriculture has on the environment - Reducing food’s environmental impacts through producers and consumers (Science, 2018) - stated in comments to the Guardian that:

“A vegan diet is probably the single biggest way to reduce your impact on planet Earth, not just greenhouse gases, but global acidification, eutrophication, land use and water use.” [33]

It’s been 11 years since the UN told us we need to shift to a plant-based diet. We don’t have another decade to spare.

- Ed Winters is Surge Co-Founder & Co-Director
earthlinged.org @earthlinged

References:

1. Livestock's long shadow. FAO.org, 2006.

2. UN urges global move to meat and dairy-free diet. The Guardian, 2010.

3. Livestock's long shadow. FAO.org, 2006.

4. Reducing food’s environmental impacts through producers and consumers. Science, 2018.

5. Reducing food’s environmental impacts through producers and consumers. Science, 2018.

6. Total global agricultural land footprint associated with UK food supply 1986–2011

7. Eating away at climate change with negative emissions. Harvard, 2019.

8. Here’s How America Uses Its Land. Bloomberg, 2018.

9. Creating a sustainable food future. World Resources Institute, 2018.

10. Cutting down forests: what are the drivers of deforestation? Our World in Data, 2021.

11. Biodiversity conservation: The key is reducing meat consumption. Science of the Total Environment, 2015.

12. What are the environmental impacts of food and agriculture? Our World in Data, 2019.

13. Controlling the Ranching Boom that Threatens the Amazon. Yale, 2009.

14. Record number of fires rage around Amazon farms that supply the world's biggest butchers. Bureau of Investigative Journalism, 2019.

15. Soy: food, feed, and land use change. TableDebates.org, 2020.

16. Global food system emissions could preclude achieving the 1.5° and 2°C climate change targets. Science, 2020.

17. Global Warming: Role of Livestock. Sejian V. et al., 2015.

18. Protecting the global ocean for biodiversity, food and climate. Nature, 2021.

19. Reducing food’s environmental impacts through producers and consumers. Science, 2018.

20. Food systems in a zero-deforestation world: Dietary change is more important than intensification for climate targets in 2050. Science of the Total Environment, 2020.

21. Reducing food’s environmental impacts through producers and consumers. Science, 2018.

22. The role of trade in the greenhouse gas footprints of EU diets. Global Food Security, 2018.

23. Food-Miles and the Relative Climate Impacts of Food Choices in the United States. Environ. Sci. Technol., 2008.

24. Grazed and Confused. FCRN, 2017.

25. Reducing food’s environmental impacts through producers and consumers. Science, 2018.

26. Eating away at climate change with negative emissions. Harvard, 2019.

27. Food system impacts on biodiversity loss. Chatham House, 2021.

28. Eating away at climate change with negative emissions. Harvard, 2019.

29. Reducing food’s environmental impacts through producers and consumers. Science, 2018.

30. Reducing food’s environmental impacts through producers and consumers. Science, 2018.

31. Reducing food’s environmental impacts through producers and consumers. Science, 2018.

32. Reducing food’s environmental impacts through producers and consumers. Science, 2018.

33. Avoiding meat and dairy is ‘single biggest way’ to reduce your impact on Earth. The Guardian, 2018.

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