Worldwide, roughly 70 billion animals are raised and slaughtered each year within the food system. Producing so many animals comes with a high price for us, for the animals, and for our planet. These costs make the United Nations Sustainable Development Goals (SDGs) much harder to achieve.
Industrial farming of animals—on land and in water—has alarming impacts on environmental and human health. Achieving the SDGs will require questioning the influence of multinational agribusiness corporations in our food systems, and rethinking how we eat and how we farm. If it is to be effective at advancing food system solutions for sustainable development, the 2021 UN Food Systems Summit must engage with the negative impacts of industrial animal production.
The first part of the high environmental cost of industrial animal farming is wasted resources. Raising and feeding so many animals requires an immense amount of land and resources—the output of 75–80 percent of the world’s total agricultural land.  Producing animal products has been the reason for as much as 65 percent of the wild land converted to agriculture since 1960. From this overwhelming investment, livestock provide humanity with less than one-fifth of our calories. Land that could have produced food for people is dedicated instead to feeding 70 percent of our livestock. Producing livestock also uses up more than one-quarter of our global water resources each year, a costly investment in what promises to be a hotter, drier world. Spending so many resources on feeding the animals we eat means we have fewer resources to build a more equitable world free of human hunger and poverty, the backbone of the SDGs.
The second part of the high environmental cost of industrial animal farming is greenhouse gas emissions (GHGs). Just as cars and trucks emit GHGs from vehicle tailpipes, livestock emissions come from animal digestion, manure, and the farming of animal feed crops. Livestock production around the world generates roughly the same amount of emissions as road transportation. If this continues, it will be impossible for the world to effectively limit climate change. This will endanger our progress on nearly all of the SDGs—especially those related to energy, environment, health, hunger, and inequality. By 2050, half of the world’s allowable GHG budget could be consumed by the food system. With the devastating effects of global climate change already on our doorstep, we simply can’t afford the high GHG cost of industrial animal agriculture any longer.
The third part of this high environmental cost is damage to ecosystems. Livestock production worldwide is a primary driver of deforestation, contributing to biodiversity loss and ecosystem collapse. Many of the nutrients in industrial fertilizers and livestock manure also wash away into nearby waterways, where they cause the overgrowth of harmful algae, which leads to dead zones that suffocate aquatic life. More and more of these dead zones have been appearing since the 1960s, jumping from less than 50 to more than 600 today. All of this damage is only the beginning. Trends suggest that global diets will likely become more reliant on animal products without radical change, driving more industrial meat production. Meeting spiking worldwide demand through industrial livestock methods would require over twice the land currently devoted to livestock production—an amount of land we simply do not have. 
Farmed Fish Are Industrial Livestock of the Sea
It is easy to think of our global oceans as vast, inexhaustible, and separated from the environmental damage of industrial agriculture. But nothing could be further from the truth.
In 2014, commercial aquaculture surpassed wild fisheries as the primary source of fish consumed by humans worldwide. In 2018, the production of farmed fish worldwide reached record-setting levels.  Unfortunately, much of this commercial fish farming is simply industrial livestock under the waves—just as cruel and environmentally damaging as industrial livestock production on land.
Industrially farmed fish live in confinement, packed tightly into underwater nets, pens, and crates. Ocean water flows freely in and out of the pens, carrying with it waste, antibiotics, and even diseases that pollute surrounding waters.
Unlike most industrially farmed land animals, who are naturally herbivores or omnivores, many of the aquatic species raised for human consumption—including salmon and shrimp—are carnivores. In commercial aquaculture, farmed carnivorous fish are raised on industrial feed produced from smaller fish and a variety of animal sources, including poultry feathers and chicken fat. This means that industrial aquaculture depends on terrestrial meat production and the capture of other fish. Roughly one-fifth of the world’s commercial fish catch becomes food for high-value species of farmed fish.
Just as production of industrial livestock on land diverts some human-edible crops for animal feed, producing industrial fish feed also diverts food sources that could otherwise support traditional human food webs, as well as the livelihoods of people who, without these traditional food sources, become vulnerable to hunger and malnutrition. Commercial fishing degrades fishing environments and competes for the same resources on which small-scale fishing communities depend.
In 1990, 90 percent of global fisheries were within sustainable levels—a catch rate that still allowed wild species to recover. By 2017, this number had fallen to less than 66 percent. To make matters worse, our oceans are also under enormous environmental threat from decades of chemical pollution, the global plastic crisis, and climate change. Together, the pressures of overfishing and environmentally damaging commercial aquaculture pose additional serious threats to ocean sustainability and to all human societies that depend on the oceans.
Public Health Costs
Regularly consuming meat and other animal products can intensify our risk of health problems. In 2015, the International Agency for Research on Cancer declared processed red meats, such as sausages and pepperoni, to be carcinogenic, and all red meat “probably carcinogenic.” Analysis of millions of individuals across all regions of the globe has also linked red meat and eggs to higher risks of chronic illness, stroke, heart disease, and premature death.
Even for those who avoid or minimize animal products, industrial livestock farming can damage health through dirtier air and water. These broad public health threats are exactly the opposite of what we need to achieve the UN SDGs related to public health.
The industrial meat industry is also building a silent crisis: Antibiotic resistance. Worldwide, 70–80 percent of antibiotics are currently used in industrial livestock. This amount could double by 2030. Many antibiotics used to treat human infections are the same ones overused in livestock, weakening their ability to defend us. Resistant infections are already causing 700 million extra hospital days per year in OECD nations, and could cause 10 million deaths per year by 2050 unless we take immediate action. The World Health Organization has named antibiotic resistance one of the biggest global threats to public health, food security, and sustainable development.
Even as the world is grappling with the devastating impacts of COVID-19, many people are unaware that industrial livestock production also contributes to the emergence of pandemics. Research shows that three-quarters of recently emerging infectious diseases in humans have come directly from animals or from the ingestion of animal-source foods. Wherever land is deforested to grow feed crops or graze livestock, the fresh contact between wild species and humans risks introducing new infections.  The global dynamics that drive pandemic risk start with decisions made on our plates, and on the desks of agricultural investors. Continuing to produce and consume industrial livestock puts us at higher risk of future pandemics.
Industrial Animal agriculture Depends on Exploitation
Producing livestock at the scale and intensity needed to support current high meat demand causes immense unnecessary suffering and endangers the welfare of both animals and people. The abuses common in industrial animal production directly endanger the SDGs related to dignified employment, fighting poverty, and building just societies.
Animal Welfare Concerns
Animals in the industrial meat system commonly endure cruel and abusive conditions including confinement, mutilation, pain, loneliness, ill health, and dirty and unsanitary living areas. As the COVID-19 pandemic caused food processing shutdowns, millions of livestock that could not be sold at market were destroyed, some by cruel practices such as the intentional shutdown of ventilation systems in the buildings where they were held. Animals in the meat industry are treated as components of an assembly line, harmed and discarded to maximize profits.
Human Welfare Concerns
Industrial meat and poultry plants in the United States employ 1.7 million people. Human Rights Watch has documented abusive working conditions including long hours, restricted breaks, low pay, exposure to toxic substances, and high danger of bodily harm. These difficult workplace conditions are maintained by low availability of alternative employment and by active suppression of collective bargaining among workers, many of whom are immigrants, women, and people of color.
Linking Human, Animal, and Environmental Health
Interdisciplinary approaches such as One Health emphasize the connections between human health and environmental health. After all, human society, food production, and development exist within the balance of natural systems. There is no future for humanity without respecting the environment and the animals with whom we share it.
The many costs of industrial livestock production and consumption are too high for us to pay: for the environment, for animals, and for our health. Now is the time for us to consider what sort of future we want. If we wish to achieve the progressive vision expressed in the UN Sustainable Development Goals, we must rethink our reliance on industrial animal products—before it is too late.
Read other posts in this series
Introduction: Our Vision for A Sustainable Food System
Part 1: Industrial Agriculture Threatens Sustainable Development explores the history of modern agriculture in the high-income nations, who built this industrial system, who has benefited from it, and what consequences it holds for a sustainable future.
Part 3: Building a Food System That Supports Sustainable Development examines structural factors contributing to the continued dominance of the industrial food system and what types of change are needed to bring about a transition.
Part 4: The Food System of Tomorrow: A Call to Action lists potential solutions at the global level, as well as specific opportunities that can spur sustainable transition within US politics and the US farming system.
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