How much land do you need to sustain yourself?

Have you ever thought about the question of how much land is needed to supply your personal consumption? Let's say you eat an average of 2000 calories per day. For most people on earth, a majority of their calories are supplied by one of the so called 'staple foods'. The most prominent of these are maize 🌽, rice 🍚, wheat 🍞 and potato 🥔 (but there are a lot more). According to Wikipedia, staple foods provide about 90% of calories that we eat. If a person would stick to a strict diet of only potato (which would not be healthy ⛔), they would need to eat 2.35 kg per day to consume 2000 calories. An average potato harvest has a yield of 17.2 tons per hectare. So to provide this person with a year's amount of potatoes would require a little under 500m2, or a 22.5m by 22.5m plot of land. Since the current amount of farmland worldwide 🌍 is 48 million square kilometers (km2), we could sustain about 96 billion of these potato eating people.

Simple diet example

However, no one is living off only potatoes, I hope. Potatoes are also not very calorie dense, so this would not be an efficient way to feed a large population. Let's construct a healthier hypothetical diet. For the sake of simplicity, we are keeping it plant based for now. An example of a very simple daily diet that covers almost all micro- and macro-nutrients would be:

• green soybeans 🥗 (250g)
• wheat 🍞 (200g)
• sweet potatoes 🍠 (150g)
• spinach 🍃 (50g)
• sunflower oil 🌻 (30g)
• sodium 🧂 (1g)

Green soybeans yield an average of 0.8 kg/m2/y, wheat 0.9, sweet potatoes 3.3, spinach 2.5 and sunflower oil 0.115 kilograms per square meter per year (assuming one harvest per year). Converting this to the area needed per person for this diet requires 114m2 + 82 + 16.5 + 7.3 + 96 square meters respectively. This results in a total of 316 m2 that would be needed per person. Quite a bit less than if we would eat only potatoes. It would only require an 18-meter by 18-meter plot of land. If everyone on earth were to eat only this diet, we could currently sustain a population of over 148 billion people 🧑‍🤝‍🧑. This is over 18x the current world population.

Adding meat into the mix 🍖

Although the diet above is somewhat realistic, there is one obvious problem: most people are not vegans 🥬. Since animals only convert a small amount of the food they eat into edible products, adding animal products will increase the area needed per person quite a bit.

Let's start with adding one chicken 🐔, so we can eat a daily egg 🥚. According to this source, the average chicken needs about 100 grams of grain per day. This adds another 41 m2 to our plot of land. Not too bad. Now let's add some chicken meat. Say we want to eat 100g of chicken per day. The average chicken yields about 2kg of meat and is eaten at an age of between 2 and 5 months (let's take 90 days). The chicken will have eaten around 9kg of wheat and produces 20 portions of 100g chicken meat. This means we will have to raise 4-5 extra chickens per person for the meat, adding 184.5 m2 of farmland 🧑‍🌾.

Our minimal non-vegan diet thus requires 542 m2 of land. This means we can sustain 88.5 billion people with current available farmland and farming practices, or about ten times the amount of people alive at this moment.

Lastly, let's add some cows 🐮. They will add milk 🥛, cheese 🧀, butter 🧈 and red meat 🥩 to our diet, making it quite well-rounded. Information about how much a cow eats varied from source to source, and it also changes a lot with the milking-cycle of the cow. This source says it is between 13-18 kg of dry grass per day for a cow that produces 28 liters of milk or 1.8 kg of milk solids. The yield of dried grass (silage) also varies, but can be around 15 tonnes / ha. This means a milk cow that eats 15 kg per day requires an additional 3650 m2 of farmland. About ten times more than our vegan from earlier. It can, however, provide milk, cheese and butter to well over 20 people. Cows 🐄 that are kept for meat are usually eaten after 18 months (550 days) and provide on average 225 kg of meat (2250 100g portions). This means one cow is enough to supply 4 people with a daily portion of meat. So let's add 1/20th and 1/4th of the cow's required 3650 m2 to our land requirement, which adds 1095 m2.

Conclusion

This would bring the total of the minimal diet supplemented with eggs, chicken meat, milk, cheese, butter and red meat to 1637 square meters per person. This is a little more than a 40 by 40 meter plot of land. Meaning that humanity could currently sustain 26 billion meat eaters (naively assuming no food is wasted). However, the world population 🌍 is currently predicted to peak around only 10.4 billion around 2050, because of declining birth rates.

This blog post 📝 is only meant as a thought experiment and to show that food production, even if we all eat meat, is not the limiting factor for population growth. I tried my best to find good sources, but can not guarantee all numbers are accurate. My hope for the future is that innovations in farming, such as indoor/vertical farming, aqua/hydroponics, genetical engineering 🧬, artificial meat production and other technologies will make growing food even more productive. This way we might be able to sustain populations of hundreds of billions all over the solar system 🌌.

How to track your time like a pro 🕒

At the end of 2023, I started a project in which I wanted to track my time, hoping this would make me spend it more productively. I wanted the solution to be self-hosted (no internet connection needed) and build on open source technology.

Tracking anything often starts with a spreadsheet. A great open source program to create and manage spreadsheets is LibreOffice Calc. Within LibreOffice calc I started by making a template. This template contains seven tabs, one for each day of the week. Within each tab there are three blocks of 8 hours. Each block contains four columns. A column for the time, the performed activity, consumptions (coffee, cigarettes, etc.), and lastly any notes or remarks. At the bottom of template I placed the names of the activities I expected to do most often. I also gave them a fitting color. I prefilled 8 hours per day with sleeping 😴 (between 01:00 and 09:00). In the end it looked similar to the spreadsheet shown below:

Because I spend quite a lot of my time behind two monitors, the spreadsheet is usually opened on my secondary monitor. After a few days, filling out the spreadsheet had already become a habit which I found quite satisfying to do. After a while of diligently logging my activities, I started to notice that seeing how you spend your time in such a visual way, really did help avoid doing undesirable activities. One of the goals was to reduce the time watching YouTube, and seeing a huge red block eating away your day is definitely more confronting than only the knowledge that you watched it for a couple of hours.

Even though tracking my time this way worked great, I still felt like there was more that could be done with this data. That is why I started working on a script 👨‍💻 that automatically gives a review of the current week. I wrote a python program that imports the spreadsheet and adds up the time spend on each activity and totals the consumptions. The output can be seen in the image below:

Don't worry, you are not having a stroke, the words are in Dutch 🇳🇱. As you might be able to see, the output is formatted in Markdown. This means it could easily be converted to HTML and displayed in a prettier way. I plan to one day turn this time tracking system into a web application (which I might publish).

How to remove the label from a glass jar 🫙

In order to test some new features (such as the fancy new gradient footer) I need to write some more text here. Unfortunately, I'm suffering from a bit of writer's block. So let me just tell you about the best way I have found for removing the labels from glass jars.

First soak the label or full jar in hot water 💧. Leave them for a couple minutes, until the paper part of the label can be removed with your nails. This leaves only the sticky residue. To remove the residue, soak a sponge in some acetone (nail polish remover 💅). Rub the scrubby side of the sponge 🧽 over the residue and it should come off easily. This will leave you with a completely clean jar which can be used for other purposes.

If you are planning to store food in the jar, don't forget to clean it thoroughly with hot water and soap. Or even better, put it in an autoclave, if you have one. A dishwasher will also work.