It is often surprising how little animal agriculture features in mainstream environmental discussions, especially considering its significant contribution to our climate crisis.
Major international analyses show that food systems, including livestock and crop production, are a major source of greenhouse gas emissions. According to the most recent global estimates, agrifood systems accounted for nearly 30 % of total human-caused greenhouse gas emissions, with livestock and land use change being substantial contributors (1). This is a conservative estimate, with some environmental analyses estimating far higher.
Greenhouse gases from livestock are not limited to carbon dioxide. Methane, which is produced by ruminant animals such as cows and sheep during digestion, has a much stronger warming potential than CO2 over shorter timescales. The Intergovernmental Panel on Climate Change identifies methane from livestock and emissions from land use change as significant drivers of human-caused warming (2).
This means that we cannot hope to sufficiently address climate change without reconsidering how we produce and consume food.
The Scale of Animal Agriculture
Although precise global tallies vary, available estimates suggest that more than 70 billion land animals are slaughtered annually worldwide, not including fish, whose deaths are typically not recorded in the same way (3). When we include fishing and bycatch, that number reaches the trillions.
Meeting the resource demands of such massive animal populations requires huge tracts of land, and produce enormous demand for water, energy, and feed crops. Every stage of production, from growing feed to transportation and processing, carries a significant environmental cost.
Studies comparing dietary patterns show that animal-based diets generally have much higher greenhouse gas emissions, land use, and water footprints than plant-based diets (4, 5). You may be surprised to learn how little meat you need to be eating to have a pretty substantial impact, too. This is one reason why researchers examining low-impact diets consistently highlight plant-based eating as a key climate mitigation measure.
Waste, Water, and Pollution
In addition to greenhouse gases, animal agriculture produces vast quantities of waste. In some major livestock-producing countries, animal manure totals hundreds of millions of tonnes per year, which is many times greater than the amount of human waste produced by even the most densely populated countries.
Unlike human sewage, which is typically treated before disposal, animal waste in industrial systems is often managed in open lagoons or stored with minimal treatment before being spread on fields as fertiliser. When mismanaged or washed into waterways during heavy rains (both are common), this manure runoff has been linked to:
- Contamination of rivers and aquifers
- Algal blooms and oxygen depletion in water bodies
- Harmful bacterial outbreaks and food-borne illnesses
Biodiversity and Habitat Loss
Animal agriculture also plays a significant role in biodiversity loss.
Large areas of land are devoted to growing crops for animal feed and providing grazing space, which leaves less habitat available for wild species. Recent life-cycle assessments demonstrate that diets high in animal products are closely associated with greater land use and the resulting pressures on natural ecosystems (4, 5).
This massive demand for land has been a major factor in deforestation and habitat destruction, especially in particularly biodiverse regions such as the Amazon basin. Clearing forests for pasture and feed crop production directly threatens countless plant and animal species and accelerates the risk of extinctions.
Diet and Climate Action
Taken together, these environmental impacts make it clear that food systems, including animal agriculture, are intertwined with climate justice and sustainability goals.
Recent research indicates that shifts towards plant-based diets could reduce overall food-related emissions by substantial margins. Estimates vary, but these are often in the range of 30% or more compared with diets high in animal products (5). Plant-based diets also tend to require less land and less water, easing pressure on ecosystems and curbing the demand for the expansion of human infastructure.
Because of this, climate scientists and environmental organisations increasingly emphasise that sustainable, plant-based diets can be a powerful complement to efforts in energy, transport, and industry. Addressing emissions from fossil fuels remains essential, but dietary change represents one of the most accessible ways individuals can lower their environmental footprint.
A Practical Step Forward
Veganism will not solve the climate crisis on its own, because no single action can. But choosing plant-based foods is an accessible and practical step that most of us can take to reduce our impact on climate change, water resources, and biodiversity, all without radical disruptions to our daily lives.
For many, adopting a more plant-focused diet represents one of the most effective personal actions available for addressing climate change and ecosystem degradation, alongside avoiding flying where possible, buying second hand, and implementing energy and waste conservation practices.
Given the urgency of the current climate and ecological crises, veganism is something that committed environmentalists, and anyone who cares about wildlife, should seriously consider.
Bibliography
- Food and Agriculture Organization of the United Nations (FAO). Latest FAO estimates of greenhouse gas emissions from agrifood systems (2022).
https://www.fao.org/statistics/highlights-archive/highlights-detail/greenhouse-gas-emissions-from-agrifood-systems.-global–regional-and-country-trends–2000-2022/en/ - Intergovernmental Panel on Climate Change (IPCC). Special Report on Climate Change and Land.
https://www.ipcc.ch/srccl/ - Faunalytics. Global animal slaughter statistics and charts.
https://faunalytics.org/global-animal-slaughter-statistics-and-charts/ - Poore, J., & Nemecek, T. (2018). Reducing food’s environmental impacts through producers and consumers. Science.
https://www.science.org/doi/10.1126/science.aaq0216 - Willett, W., et al. (2024). Environmental and climate benefits of plant-based diets. Nature Communications.
https://www.nature.com/articles/s41467-024-45328-6
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