A plant-based diet is better for the environment

Global warming, along with land- and water use, resource waste, biodiversity loss, and the rise of zoonoses are just a few of the global problems we are currently facing. These problems are exacerbated by a growing global population and a corresponding increase in demand for animal-based products. Dietary change is urgently needed to help solve these problems.

Our planet has a certain capacity in terms of how much it can take before a vital system, such as the planetary climate, reaches a critical point, sometimes called tipping point. Reaching those points, or even exceeding them, can cause irreversible and major changes to some of our earth systems, leading to global warming or biodiversity loss, as well as other negative impacts.^1 2 The global food system, together with current consumption patterns play a major role in exceeding some of these planetary boundaries. Changing what we eat can be beneficial for both human and planetary health.

Climate crisis

The current climate crisis is a massive threat to food security, water availability, and biodiversity, worldwide, as well as a major cause of environmental disasters. According to the Intergovernmental Panel on Climate Change (IPCC), our current food system is responsible for up to a third of global greenhouse gas emissions.³ Animal agriculture accounts for about 20% of global emissions.⁴ The goals set in the Paris Agreement in 2015 – aimed at limiting global warming to 1.5°C in order to avoid the worst impacts of global warming – will not be possible if current food-consumption behaviours are maintained, even if current fossil fuel emissions are completely halted.⁵

Scientific research, along with organisations such as the IPCC, agree that a shift towards more plant-based diets can reduce food-related greenhouse gas emissions significantly.⁶ On an individual level, shifting to a plant-based diet has the potential to reduce one’s personal food related greenhouse gas emissions by up to 50%.^7 8 9 10 On a global scale, if everyone adopted a plant-based diet, global foot-related emissions could be reduced by up to 70% by 2050, compared to a scenario in which current dietary practices are maintained.¹¹

Water use

The world is in the midst of a water crisis. Water scarcity already affects more than 40% of the global population.¹² Globally, agriculture is the biggest consumer of freshwater, using 70% of freshwater for the irrigation of fields and for rearing farmed animals on land and in aquaculture farms.¹³ Growing feed crops is responsible for 20% of global freshwater expenditure.¹⁴

When talking about water use, we often refer to the ‘water footprint’, which indicates how much water is needed for the production of certain goods, such as food. The water footprint is a combination of the freshwater (blue water) used directly for production that comes from groundwater and surface waters, and water from precipitation (green water) that is stored in the soil and is potentially available for plants. The amount of water in different categories depends on the specific product and can vary from region to region. In terms of a water footprint, the production of a 150-gram beef burger requires 2,350 litres of water, while a comparable soya-based burger needs only about 158 litres.¹⁵ The water embodied in 1 kg of beef is the combination of the water used to grow the feed, the water a cow needs to drink, and the water required to clean the animal sheds.

Going further, on an individual level, you could potentially reduce your water footprint by 25 – 55% by moving to a more plant-based diet.^16 17 This could represent a total reduction of between 1,200 and 2,000 liters of water each day.^18 19 In terms of fresh water, there also might be a significant reduction²⁰ – however, this depends on what is eaten and where it was produced.²¹

Land use

About half of the world’s habitable area is used for agriculture.²² Of this, 80% is used for producing animal-based products (which also contributes to up to 60% of food emissions), although they only provide about 18% of our calories.²³ Most of this land is used as pasture, while the remainder, which comprises large areas of cropland that could potentially be used to grow crops for direct human consumption, is used to grow feed crops. According to the FAO, about a third of global cropland is used for feed crops²⁴ and while this global average is already very high, countries with a high share of animal protein in their diets use even more cropland. For example, more than 50% of Germany’s domestically cultivated cropland is used for the production of feed crops. In addition, Germany effectively ‘imports’ huge amounts of land – twice the area used for domestic crop-production. In total, two thirds of Germany’s cropland footprint is used for livestock production.²⁵

Waste of resources

It is a sad fact that a third of all food is either lost due to inefficiencies in the supply chain or wasted at the consumer or retail level.²⁶ While much of this waste occurs at the consumption level, there is another important factor to acknowledge. As stressed above, we feed huge amounts of crops to animals, crops which could potentially also be consumed directly by humans. About a third of all grains and two thirds of soya beans, maize, and barley are fed to animals.²⁷ Not everything we feed to so-called livestock can also be used for human nutrition (e.g. grass from pastures), and in some regions of the planet, it is simply not possible to grow enough crops for human consumption. But, particularly in the west, a large part of what we feed to animals is in direct competition with human needs.

The greatest losses in food production are linked to the production of animals for food.^28 29 30 In biology, it is common knowledge that, with every step in the food chain, a considerable amount of energy is lost as it is used for metabolism, movement, and other processes. ‘Feed conversion efficiency’ describes how many kilograms of feed are needed to produce a single kilogram of meat, milk, or eggs. A study by Shepon at al. (2016) showed that on average, only about 8% of plant proteins are converted to animal proteins – which means that, for every kilogram of animal protein, about 12 kilograms of plant protein is needed.³¹ When comparing animal-based products with nutritionally equivalent plant replacements, between 40% and 96% of food is lost.³²

Industrial animal husbandry uses larger amounts of protein that could be used for direct human consumption.³³ In the US, replacing meat with plant alternatives could reduce the need for cropland and nitrogen-fertiliser use by 35-50%, and reduce greenhouse gas emissions to a similar extent.³⁴ Another example from the US showed that an increase in plant-based diets could feed twice the country’s population.³⁵ On a global level, we would be able to feed about 10 billion people by reducing the amount of animal protein in our diets.^36 37 38

Loss of biodiversity

Biodiversity is crucial to the functioning of ecosystems and is necessary for healthy soils, water regulation, carbon storage, food production, pollination, and healthy wildlife populations.³⁹ Yet, a large part of the food we consume comes from only a small number of species, and the ways in which we produce our food places further pressure on biodiversity.

We have entered the era of sixth mass extinction.^40 41 About 25% of all species currently face extinction, many of them within decades.⁴² Agriculture is one of the main reasons for this huge decline in biodiversity, as we are changing the surface of this planet within such a short period of time that it renders nearly any adaptation by wild species impossible.

The world’s forests are home to over 80% of terrestrial plants and animals,⁴³ yet nearly 70% of cleared lands in the Amazon are used as cattle pastures.⁴⁴ Deforestation could be reduced by up to 55% if animal consumption was reduced.⁴⁵

A recent study looking into 20,000 terrestrial vertebrates projected that about 88% of these species will lose their habitats to agricultural expansion by 2050 if current dietary patterns and agricultural practices are maintained. In order to prevent these losses, it is important to eat less meat and animal-based products, reduce food waste, sustainably increase crop yields, and implement international land-use planning.⁴⁶

Infectious diseases and Antibiotic resistance

Zoonoses are diseases of animal origin that have spread to humans. Mounting evidence suggests that the recent increase in zoonotic events is directly linked to humans’ increasing interactions with animals, particularly in terms of food sourcing. Our appetite for meat, eggs, and dairy has brought us into ever-closer contact with both domesticated and wild animals by keeping ever more of them in increasingly confined spaces and invading ever more of their habitats. Together with human-made destruction of the environment, this increases the likelihood of viruses jumping the species barriers, consequently resulting in new zoonotic diseases.

What you can do

By reducing your consumption of meat, dairy products, fish, and eggs, and shifting to a more plant-based diet, you can directly contribute to helping solve many of the global problems mentioned above. With a shift in diets, 10 billion people could, in theory, be fed – without putting a further burden on the environment and the health of the planet.⁴⁷

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