Land

A vegan world would need about 75% less farmland

By WhyStopHarmingAnimals.com

If everyone on Earth ate a plant-based diet, the world would need about 75% less farmland[1]. Our World in Data, drawing on Poore and Nemecek’s 2018 study in Science, puts current agricultural land at about 4.1 billion hectares and a plant-based world at about 1 billion[1][2]. The land left over, roughly 3 billion hectares, is an area on the order of North America plus Brazil, and it could go back to forest and wild habitat.

The reason is simple. To eat animals, we first have to grow plants for them, and most of what the animal eats never comes back as food.

Most farmland feeds animals

Farming already covers about 44% of the world’s habitable land, around 48 million square kilometres. About 80% of that farmland is used for meat and dairy, either as pasture for grazing or as cropland growing feed[3]. In return, Poore and Nemecek found, meat and dairy supply about 18% of the world’s calories and about 37% of its protein[2]. The rest of humanity’s calories and protein come from plants grown on the remaining fifth.

The loss happens inside the animal. A cow, pig or chicken spends most of the energy in its feed on staying alive, and only a small share turns into meat, milk or eggs. Beef is the worst case: it returns only a few percent of the protein that went into the animal. Cassidy and colleagues, writing in Environmental Research Letters in 2013, measured farm output as people nourished per hectare instead of tonnes harvested[4]. By that measure, shifting crop calories from animal feed to people would raise the number of people each hectare feeds[4], because a large share of the world’s crop calories never reach a human plate[4]. They go through an animal first[4].

Two models, the same answer

The 75% estimate comes from Our World in Data’s reading of Poore and Nemecek[1][2]. Their global analysis found that meat and dairy take the vast majority of farmland[1][2] and produce about 60% of agriculture’s greenhouse gases, and that avoiding them is the single biggest way to cut the impact of what you eat.

Springmann and colleagues reached a similar number by a different route[5]. Their 2018 paper in Nature modeled how the food system could stay within planetary boundaries for land use, climate and other limits[5]. Without a shift toward plant-based diets, they found, staying within the land-use and climate boundaries was not feasible even with fixes on the production side[5]. Completely plant-based diets cut global land use on the order of 70% in their analysis[5].

Most of the land a vegan world would free is pasture, with the rest coming from cropland that now grows feed. People would still need cropland, but far less of it, because the crops would feed people directly instead of passing through an animal.

What lives on that land now

Using most of the world’s farmland to raise animals[3] has changed who lives on the planet. Our World in Data, using figures from Bar-On, Phillips and Milo’s 2018 census of life on Earth in PNAS[6][7], shows that if you weigh every mammal that isn’t human, about 94% of the total is cows, pigs and other farm animals[6][7]. Farm animals outweigh wild mammals about 15 to 1[6][7], and counting land mammals alone, their share is 97%[6]. Wild animals were pushed off the land to make room for animals bred to be killed. Forests are still being cleared for the same reason[8]. Our World in Data, drawing on Pendrill and colleagues, puts beef at about 41% of commodity-driven deforestation worldwide, the largest share of any product[8].

Limits of the estimates

These are global models, and the exact figure depends on the assumptions: about 75% in Our World in Data’s estimate[1] and on the order of 70% in Springmann’s[5]. Some grazing land is too dry or steep to grow crops, so not every hectare freed from pasture could become a field. It could become forest, grassland or wetland again, which is the point. Neither estimate depends on new technology or higher yields. The land comes back because the animals no longer need to be fed.