Animal agriculture: at what cost?

September 13, 2022

The costs to our planet and the climate are becoming insurmountable. But we can’t solve a problem until we acknowledge it. Let’s get a few things straight.

Producing animal-based food products affects our planet in dramatic ways, and at what cost? Not only do we need to consider how effective and efficient they are in satisfying our nutritional requirements, but also their impacts on the environment and climate change.


In most aspects of economic activity, governments and corporations demand increasing levels of efficiency and productivity. However, they seem to have generally ignored the overall food production system in that regard. How else can we explain the continued large-scale production of animal-based foods when animals are a grossly and inherently inefficient source of nutrition. For example, it takes 20 kilograms of plant protein to produce just one kilogram of beef protein, and five kilograms of plant protein to produce one kilogram of pig or poultry protein. In fact, 77 percent of global soy production is used to feed farmed animals.

These huge levels of inefficiency mean we currently require far more resources, including land, to feed people than would be required if we were to adopt a non-animal diet. Even worse, the current system is not only inefficient but also ineffective to the extent that more than 700 million people globally are chronically undernourished. Based on a 2013 study from researchers at the University of Minnesota, a transition away from animal agriculture would give us the capacity to adequately feed these people many times over.

The scale of animal agriculture industries also exacerbates other problems to which it contributes, such as greenhouse gas emissions and resultant climate change.

77 percent of global soy production is used to feed farmed animals.


Humans and all members of the natural world now face an existential threat from climate change. Animal agriculture’s impacts are generally understated in official greenhouse gas reporting because relevant data is either classified under non-livestock headings, included on the basis of conservative calculations, or not included at all.

Classification under non-livestock headings – Land clearing for animal agriculture and other purposes is not allocated to the responsible sector. Rather, it has a stand-alone classification known as ‘land use, land use change, and forestry’. This arrangement reduces our ability to recognise and address the ongoing causes of climate change to the extent that they relate to our use of land.

Conservative reporting – A 100-year time horizon is generally used for calculating the global warming potential (GWP) of non-carbon dioxide greenhouse gases. However methane – a major factor in animal agriculture’s climate change impacts – generally breaks down in the atmosphere to a significant extent in nine to 12 years. Therefore, a 100-year GWP (which shows the average impact over a period of 100 years) greatly understates its shorter-term impact. This is critical when considering the impact of near-term climate change tipping points, with potentially catastrophic and irreversible consequences.

Some meat industry participants argue erroneously that methane’s relatively short atmospheric lifetime means that a farming business can continue to emit the gas, provided its herd size is stable. However, methane’s shorter atmospheric lifetime is already allowed for in estimates of its GWP. What’s more, methane has accumulated in the atmosphere at a much higher rate than carbon dioxide since pre-industrial times, and it’s the atmospheric concentration of a greenhouse gas, rather than its emissions per se, that determines its warming impact. The meat industry also argues that biogenic (non-fossil) methane such as that emitted by cattle is less harmful than fossil methane. However, according to the Intergovernmental Panel on Climate Change, the GWP multiplier of non-biogenic methane is close to that of the fossil variety.

Omissions from official greenhouse gas reporting – One key omission is the loss of carbon sequestration that arises from land clearing and other changes in land use. This failure has massive implications when we consider the land area used for animal agriculture. Allowing for loss of sequestration, a 2018 paper in the journal Nature found the global average greenhouse gas costs of dairy and beef to be three to four times higher than previous estimates from the UN Food and Agriculture Organization, which only used emissions from each year’s agricultural expansion. They also reported that the greenhouse gas emissions intensity of beef is 26 times that of pulses (including chickpeas and lentils) and 73 times that of soybeans.

Image: Sergio Souza on Pexels


We can only touch on the many costs of animal agriculture here, but water pollution, water usage, land degradation, invasive species, and biodiversity loss all need to be acknowledged.

Blue carbon – Consumption of fish and other sea animals has had a dramatic impact on kelp forests and vegetated coastal habitats, which have the ability to sequester and store large amounts of carbon. Vegetated coastal habitats, including seagrass meadows, mangroves, and salt marshes, are the most carbon-rich ecosystems in the world, capturing carbon 40 times faster than tropical rainforests. Kelp forests provide similar benefits. Such impacts are generally ignored in official greenhouse gas reporting.

Water pollution – Intensive dairying practices impact fresh water, including fertilisers and effluent entering the water system, resulting in excessive levels of nitrates. In rivers, these nitrates result in toxic algal blooms, which extract oxygen and make the water unsafe for fish and other inhabitants. Effluent also adds pathogens such as E. coli. In New Zealand, for example, 60 percent of rivers now have unacceptable levels of contamination, with the figure increasing to 95 to 99 percent in pastoral, urban, and non-native forested areas. The nitrates also enter groundwater systems that 50 percent of New Zealanders rely on for drinking water. Tragically, they are carcinogenic.

Land use – In dramatic contrast to the inefficiencies of animal agriculture, a 2019 paper in the journal Science reported that non-animal agriculture occupies a mere 17 percent of farmland globally while providing 63 percent of protein and 82 percent of calories. The report’s authors estimated that a general transition away from animals as a food source would reduce the area used as farmland globally by 76 percent (including 19 percent of arable land). This would release an area equal to Africa or four times that of Australia. That’s 31 million square kilometres that would be available for reforestation, afforestation, or rewilding!

Non-animal agriculture occupies a mere 17 percent of farmland globally.

Loss of biodiversity – Biodiversity loss and the resultant pressure on wild animals was highlighted by a 2018 paper in the Proceedings of the National Academy of Sciences, which reported that the biomass of farmed animals (excluding farmed birds) is now 15 times that of wild animals. The biomass of farmed birds is more than double that of birds in the wild. Biodiversity is essential for the processes that support all life on Earth.


We need to recognise and acknowledge a problem before we can solve it. In the same way that entrenched economic interests continue to resist ending the use of fossil fuels, the animal agriculture sector resists a general transition away from its products. However, we will not overcome climate change and other threats without such a move. We must give our magnificent planet the opportunity to recover and thrive for the benefit of all its inhabitants – including us.

Lead image: Scharfsinn on Shutterstock

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