Animal agriculture requires more land to produce the same amount of food energy than equivalent plant-based agriculture. With about 75% of global agricultural land being used for animal agriculture, much of which is attributed to crops grow for animal feed.
As global human populations grow there will be a growing demand for food and if we try to meet this demand by producing more animal flesh we will quickly run out of land and other resources. Future food requirements could be met by reducing the demand for animal flesh. This would make animal feed crops available for human consumption.
To reduce the impacts of animal agriculture we will need country level information to inform strategies for mitigation. This is exactly what a group of scientists did in a paper published in the journal Global Environmental Change. They estimated the total land footprint associated with livestock supply of the United Kingdom (England, Scotland, Wales, Northern Ireland).
What did they do?
To do this they calculated the amount of cropland and grassland that was used to produce the animal flesh consumed by the UK. They did this for each year between 1987 and 2010.
To calculate the amount of cropland used for animal feed vs human food they first worked out how much crop feed and food the UK was consuming. For example, they would figure out how much wheat crop was being used for feed vs food. This included both home grown crops and imported.
When calculating the total amount of feed consumed they included home grown feed, imported feed and the feed that was associated with the growth of important animal flesh. So for every tonne of chicken flesh important into the UK, the crops that were needed to grow the chicken were directly added to the UK’s total ‘feed’ use. They calculated the amount of cropland for each type of animal flesh based on the animals Feed Conversion Ratios (FCR).
Calculating the amount of grassland used by the UK was more complicated and a bit beyond what we can go into here. But basically for every country that supplied animal based food products to the UK they worked out the amount of grassland used to produce the products. For example, if the USA supplied Cow Flesh, Sheep’s Flesh and Cows Milk to the UK, they work out how much grass land was used to grow each tonne of that product in the USA.
To top all of this off they also calculate the calorie and protein content associated with the animal flesh and human crops consumed by the UK.
What did they find?
The total land footprint of the UK food supply in 2010 was 23,723 kha, which included 14,890 kha of grassland footprint, 5,176 kha of cropland footprint for animal feed and 3,657 kha for human food. The total land area of the UK is 24,361 kha which means that the land area the UK uses for producing food is equivalent to 97.3% of its total size. That is larger than England, Scotland and Wales combined!
The land footprint associated with animal products was 20,066 kha, which makes up 85% of the UK food supplies total land footprint. That is a little bit smaller than the total land area of England and Scotland combined.
The authors show that in 2010 about 38% of the total UK crop supply, which included domestic production and imports but not exports, was used for animal feed. With more than half of all cereals, pulses and oil crops being used for animal feed. In particular, 87% of all UK barley supply and 93% of all soya bean supply goes to feeding animals.
In 1987, around 55% of the cropland footprint for feed was found in countries outside of the UK. This increased to 64% in 2010; which means the UK is effectively exporting its animal agriculture associated land use.
The grassland footprint that was required to produce the UK’s animal products was almost 3 times larger than the cropland feed footprint. About 44% of the UK’s grassland footprint is used to produce cow flesh. By 2010 the average area required to produce 1kg of cow flesh was 52 m2, sheep flesh was 141 m2 and milk 2.5 m2.
Despite animal based products using 85% of the UK food supplies total land footprint they only produced 48% of the proteins and 32% of calories consumed by humans. Alternatively, cereals for human food used 6% of the UK food supplies land footprint and produce about 33% of the protein consumed by humans.
What does it mean?
The results in this study really speak for themselves. The land footprint of the UK food supply is dominated by animal agriculture, with only 15% of the footprint being used for growing food for direct human consumption.
If we break up the UK food supplies total land footprint into 1% chunks then it is clear that land used to grow animal based foods is extremely inefficient at providing protein for humans. For every 1% of land dedicated to animal production 0.56% of the UK’s protein was produced. In contrast, for every 1% of land dedicated to cereal production 5.5% of the UK’s protein was produced. That means that the same amount of land dedicated to producing cereals delivers about 10X more protein than it would if it were used to grow animal flesh. This highlights the huge resource inefficiencies in using animals flesh for food.
The authors suggest that a dietary change away from animal flesh could significantly reduce food supply land footprints.
A limitation of the study was that they used only one FCR to calculate the amount of cropland and grassland area required for animal products from different countries. These FCR’s were based on UK ratios which might not be truly representative of animals in other countries. For instance, this means that cows in Australia were assumed to have the same FCR as cows in the UK. They predicted the effect that this might have on their results and found that it wasn’t drastic but could cause small differences in their results.
Finally, it would be great to see similar studies done for other countries. It would be also be interesting to calculate what a country’s total food supply land footprint was if animal based consumption were replaced with 100% plant based consumption.
What does it mean for veganism?
This will be an important paper to reference when speaking to people about the environmental impacts of animal agriculture. It clearly shows the hugely disproportionate land resources that are required to produce animal based foods compared to plant-based foods. But keep in mind this information is about the UK.
Written by Adam Cardilini