The original reason that we created Hungry Pumpkin was to show (with science!) that vegan food can be tasty, simple, nutritious, and affordable. However, as our planet is increasingly victimised by global warming and growing populations, it becomes more and more important to be aware of the environmental footprint of our eating habits.
According to the United Nations, by 2050 the world’s population will reach nearly 10 billion. As each of us makes many small actions each day, these add up when multiplied by such a large population number. As such, even small acts such as cycling to work, buying local, and using reusable bags have a large impact when practiced by many. These actions may be small, but they start with each of us!
The fact that climate change is occurring is now undeniable (at least by those who follow science). Though it is difficult to distinguish between man-made climate change and natural shifts in global climate, it is clear that such changes are largely influenced by large CO2 emissions, introduction of dangerous substances into the environment (plastics, pesticides, etc.), and by the destruction of natural ecosystems (often for building, wood, or to change land to agricultural space).
Food is the basis of our survival, and producing it inherently places a burden on the environment. There are many different types of food that we can make, and choosing the right kinds can immensely reduce the burden that we place on the planet. But choosing the “right” food is not simple.
How can we scientifically calculate the impact of growing a particular food?
To begin with, most of us are by now aware that producing foods of animal origins is much more burdensome than producing plant-based foods. This is because more steps are involved, and animals use energy and produce waste. To create a single unit of animal-based food involves the use of multiple units of plant-based foods. This is not only inefficient environmentally, but also from the standpoints of growing populations and declining access to foods. The global wealth gap and the wastefulness of many of the richest countries on the planet also plays a large roll in this issue.
One unit of food can be one kilogram, one kilocalorie, or the equivalent of 100 g of protein. No matter which way you define it, the end result is the same: animal-based foods take more resources, produce more waste, and have lower yields than plant-based foods. This is because we add in the extra step of producing food for the animals that are to be consumed. A 2018 English survey found that an average human daily consumes 594 kilocalories of animal-based food (meat, cheese, eggs), for the production of which 5550 kilocalories of plant-based food was needed. This means that the animal uses almost 90% of the plants’ energy, and thus is lost from the human diet. As such, we get back only 10% of the calories that we invest in animal-based food production. Of these 5550 kilocalories that are consumed as feed, 1738 come from corn, soybeans, potatoes, and other plants that humans could directly consume. The remaining 3812 comes from hay and other substances that are not consumed by humans, but in order to produce them requires a large amount of land and natural environment destroyed as well as extensive fertilising and irrigation.
Sceptics will say that healthy food requires protein, mistakenly believing that there is not enough of this in a plant-based diet. Not only have we consistently proven this wrong at Hungry Pumpkin (see link), but the logic also does not line up; humans are not the only animals that need proteins. If other animals can get enough protein from plant foods, why not us? This was confirmed by the same English study, stating that feed containing 139 g of plant protein is needed to create 38 g of animal protein (this is the amount of animal protein that is produced globally per person per year). Almost 3/4 of the protein is therefore used by the animals and thus lost from the human diet. Of these 139 g of protein, 89 come from plants that humans can eat, while the remaining 52 grams is from hay and similar plants. As such, animals that are farmed for food at not protein producers, but protein consumers. Similar calculations have been made for vitamins and minerals, and the results are the same: more nutrients go into producing animal-based foods than we get back from them. This shows that eating plant-based foods puts less of a strain on the environment.
But different animal- and plant-based foods have different environmental footprints. This becomes difficult to calculate as there are many factors to be taken into account (pollution, loss of natural habitat, water usage, greenhouse gases, soil erosion and damage, methods of harvesting, transportation of feed, methods of slaughter, final transportation of animal products). A good assessment of the environmental burden of a food will take into account details as minute as the source of the water (is it from a large river? or a depleted groundwater source?) and what happens to it after use (returns to nature unchanged, becomes waste, evaporates).
The most burdensome form of cultivation for the environment is that of ruminants, such as cattle, sheep and goats. To produce enough beef to give 100 g of protein, an equivalent of 30 kg of CO2 is put into the environment. To produce this same amount of protein involves greenhouse gas release equalling 11kg of CO2 for cheese, 7.6 kg for pork, 6 kg for farmed fish, 5.7 kg for poultry, and 4.2 kg for eggs. This may not seem like much, but this is for only 100 g of protein! Next time you are in a store, pick up something that is 100 g and see if you think it is worth leaving such a dangerous footprint behind for such a small outcome. For plant foods, the environmental load is much lower, with 100 g of protein arising from the releas of 1.2 kg of CO2 for peanuts, 0.8 kg of CO2 for average legumes, 0.4 kg for peas, and 2.7 kg for cereals. That being said, there is also variation between producers based on their methods; some cereal production creates less than 2 kg of CO2 per 100 g of protein, while others are above 5 kg!
With regards to destruction of natural habitats to create farming areas, we see a similar pattern emerge: to produce 100 g of protein from beef requires 110 square metres. Cheese requires 41 square metres, 11 for pork, 7 for poultry, 4 for peanuts, 3 for peas, and 5 for cereals.
This study analysed only some of the most important foods of plant and animal origin, but we also know that some other foods are very demanding in terms of production, processing, and transport, and thus more burdensome for the environment. Tomatoes, for example, are about 3 times worse on the environment than onions in all parameters, such as CO2 emissions, surface use, water consumption, and groundwater pollution. Again though, this is the average; the most eco-friendly tomato growers are better than the worst onion growers!
If avocados are your favourite food, we regret to tell you that these tasty fruits are in fact rather sinister; a great deal of water is needed to produce them, while increasing demand has led to increased deforestation to keep up with consumption; transportation is also a large issue for these little green treats. Similarly, palm oil is a huge contributor to deforestation, but sustainable production also exists. This all being said, as much as 90% of all crop-growing areas are used to produce feed for livestock production.
So, how do we handle all of these numbers and how do we do our best to reduce our burden on the environment? Some well-known guidelines are best followed here: a plant-based diet is a great step, but if you’re not there yet than focus on local and in-season foods. Eating fewer processed foods and food with less packaging also helps. Using your own shopping bag rather than plastic and walking or biking to work or the store are also great options. It is important to remember though, every small action helps! The world does not need a few perfect vegans who produce zero waste, it needs many people like you who try to consume food more responsibly and cut back on waste as much as possible. We each have a role to play in this, for the safety of our planet and for all who live upon it.