Changing our diet for a wilder world
Status: early draft
It will be focused on Western Europe (Austria, Belgium, France, Germany, Liechtenstein, Luxembourg, Monaco, Netherlands, Switzerland) using data from the Food and Agriculture Organization (FAO) of the United Nations, but it could easily be transposed to other industrialized regions. All tables were generated by a script published on GitHub.
Western Europe was home to 191 million humans in 2013 and that number should stabilize around 200 millions by the year 2040. At the same time 573 million chickens, 65 million pigs and 42 million cattle, among other animals, were kept in farms to feed them.
Paris, France (Google Maps)
Western Europe has a land area of 109 million hectares. Most of it was covered by deciduous trees before human settlement and the beginning of agriculture, but nowadays the forests are reduced to 34 million hectares while crops and pastures use 28 and 25 million hectares respectively.
A closer look at the current forests shows that there is virtually no wilderness left in Western Europe, it is one of the most endangered ecosystem in the world. The vast majority of the remaining forests are heavily exploited and about a third of them are not much more than monoculture tree plantations.
|..... Permanent crops||1.35|
|..... Temporary crops||26.40|
|..... Fallow land||0.74|
|..... Permanent meadows and pastures||17.83|
|..... Temporary meadows and pastures||6.72|
|..... Primary forests||0.16|
|..... Planted forests||9.97|
|..... Naturally regenerated forests||24.31|
Most cattle (and sheep and goats) live in pastures, while most chickens and pigs (and humans) live indoors. Crops produce food for both humans and their livestock.
Pine plantations, Landes, France (Google Maps)
The majority of the space taken by crops is used for cereals, representing 18 million hectares of plantations, with 4 more used to produce oils. The remaining plants (fruits, roots, vegetables) take less than 3 million hectares.
NOTE: The area of crops on this table (25M hectares) differs from the previous table (28M hectares), see: QC Methodology (FAOSTAT)
The following table is more complex, but it allows us to see how many million tonnes of a type of crop is used for human food (directly or processed) and livestock feed.
NOTE: Some items on this table differ from the previous table. For example beers and wines are now excluded from cereals and fruits respectively and counted in drinks.
Most of the crops used to feed livestock are cereals. Of the 104 million tonnes available in the domestic supply, about 1/3 goes to human food and 2/3 to livestock feed.
Furthermore, as supply is defined by
production + import - export - changes in
stocks, assuming the same balance for the 126 million tonnes of cereals
produced, about 11 million hectares of cereal crops out of 18 according to the
previous table are used to feed livestock.
Cereal fields, Beauce, France (Google Maps)
If we look at the food supply (in kcal/capita/day) we can see that animal and vegetal products represent respectively 1/3 and 2/3 of the diet in Western Europe.
Plant-based diets have a long history around the world and the modern widespread availability of dietary supplements (vitamins B12 and D most notably) means that a strict vegan diet, properly planned, can be as healthy as any omnivore diets.
In terms of calories available to humans, converting crops to animal products is less efficient than directly consuming those crops in the first place, so a much smaller area of land for crops would be needed. The same might be true for other products like beers and wines for example.
NOTE: Add numbers and references to the previous paragraph.
It should be noted that some areas used for pastures are not suitable for crops and in those areas a diet including some animal products might be more efficient from the point of view of maximising the number of humans living on the land. But this essay is about improving biodiversity while stabilising the current human population of industrialized regions like Western Europe.
Cattle in a pasture, Alps, France (Google Maps)
If all humans living in Western Europe shifted to a plant-based diet, most 25 million hectares of pasture and at least a third of the 28 million hectares used by crops (mostly cereals used to feed the livestock) could be freed from agriculture, while a smaller portion of that cropland would be kept to increase the quantity of vegetal products available for direct human consumption. The result of this change, after rewilding the land, could double the amount of forests and provide a lot of space required to protect biodiversity.
A full conversion of the population to a plant-based diet seems, of course, slightly utopian at the moment, but even a moderate shift toward less meat consumption would progressively allow the creation of more natural reserves.
Bialowieza Forest, Poland (Google Maps)
In less industrialized areas there are more remaining forests, crops take less space than pastures and are less used to feed the livestock, and humans eat less animal products. But the population is still growing and adopting more and more a lifestyle similar to Western Europe.
World populations (in millions):
World land use (in million hectares):
|.. Arable land and permanent crops||1,571.97|
|.. Permanent meadows and pastures||3,309.64|
|..... Naturally regenerated forests||2,437.26|
|..... Planted forests||286.93|
|..... Primary forests||1,281.56|
World crops areas (in million tonnes and hectares):
World crops balance (in million tonnes):
- Gerbens-Leenes, P. W., and Sanderine Nonhebel. “Consumption patterns and their effects on land required for food” Ecological Economics 42.1-2 (2002): 185-199.
- Scarborough, Peter, et al. “Dietary greenhouse gas emissions of meat-eaters, fish-eaters, vegetarians and vegans in the UK” Climatic change 125.2 (2014): 179-192.
- Sabaté, Joan, and Sam Soret. “Sustainability of plant-based diets: back to the future” The American journal of clinical nutrition 100.suppl_1 (2014): 476S-482S.
- Aleksandrowicz, Lukasz, et al. “The impacts of dietary change on greenhouse gas emissions, land use, water use, and health: a systematic review” PloS one 11.11 (2016): e0165797.
- Erb, Karl-Heinz, et al. “Exploring the biophysical option space for feeding the world without deforestation” Nature communications 7 (2016): 11382.