Video Written, Produced, Filmed, and Edited by Sierra Glassman

 Think of an apex predator. A carnivore at the top of the food chain, like a wolf, lion, or eagle. Why do you think no species has evolved to eat these animals?

Hi, I’m Sierra with Eat For the Earth, and in series we will learn about the relationship between animal agriculture and the environment.

To understand why apex predators aren’t challenged, we have to know a basic concept in ecology: the trophic cascade. It is basically a food chain with levels. Here you can see the producers, the primary consumers, and the secondary consumers. Producers, or plants, create their own energy. They take their nutrients from the sun and the ground. Primary consumers are herbivores. They get their energy from eating plants. Secondary consumers eat primary consumers (and producers, if the species is omnivorous). For example, in a beef-eating society, soy is a producer, cows are primary consumers, and humans are secondary consumers.

One of the most interesting applications of the trophic cascade is the energy pyramid, which depicts the energy contained at each level of the trophic cascade. Why is it shaped like a pyramid? Well, an ecosystem has only so much energy, and, unfortunately, energy transfer isn’t exactly efficient. Each time something consumes an organism from the level below it, 90% of the energy that that organism stored over its whole life is lost. Only roughly 10% of the energy it consumed throughout its life is available to the next level of the pyramid. It would make sense then, that eating the producers, plants, is more energy-efficient than eating primary consumers, like livestock.

The reason why there can’t be an infinite chain of predators eating each other is because ecosystems have finite resources and energy is always lost through consumption. Because eating animals is less efficient than eating plants, animal farming uses way more resources than plants.

This plays out in animal agriculture’s land use. Meat and dairy production take up a whopping 83% of our farmland, but farmed animals only provide 37% of our protein and 18% of our dietary calories. That huge percentage isn’t all taken up by cows on pastures. It is also taken up by monoculture crops grown specifically to feed animals.

Because of the large amounts of plants used to feed animals, beef and lamb take 100 times more land to produce a Calorie than peas and tofu. Also, if used for livestock, one acre of land can only produce up to 480 pounds of meat, while if allocated to plants, could yield over a 20,000 pound harvest.

Even protein is wasted by meat and other animal products. For every 100 kilograms of protein fed to the animals, egg, dairy, and poultry only yield 10-15 kg of protein. Beef is the worst, only producing 3kgs of protein per 100 kg of feed protein. This is accentuated by the land use of animal products – beef and lamb take 100 times more land than peas and tofu to produce a single gram of protein!

This amount of land and crops used by animal agriculture is astounding. Just one company, Tyson Foods, uses an area twice the size of New Jersey to grow crops to feed its animals.

With this “wise” usage of our Earth’s surface, how does the animal industry manage our water? 3% of all water is freshwater, and more than half of that is in glaciers. It is a rare and finite resource.

When comparing plant food and animal products with the same nutritional value, water use is always higher for the animal product. Water use per gram of protein for milk, eggs, and chicken is one-and-a-half times larger, and for cows 6 times larger, than the water footprint of beans. If you replace meat by protein rich plants like beans and nuts in your own diet, you could lower your personal food-related water footprint by 30%!

Agriculture accounts for about 70% of the world’s freshwater usage, and animal ag takes up 29% of agriculture’s water usage. So, livestock use 20% of our global freshwater (Mekonnen and Hoekstra, 2012). That’s a lot.

We use tremendous amounts of water to grow tremendous amounts of food for animals who provide a fraction of the sustenance of the resources that they take. This waste of valuable resources in times of increasing scarcity is unacceptable.

But, how many resources could we save if we stuck to plant foods? The largest use of the Earth’s ground is farmland. In fact, it covers 43% of all ice and desert-free land, an astounding 4 billion hectares. If we eliminated animal agriculture, we could feed the same amount of people with only 1 billion hectares. This would free up an area the size of North America and Brazil combined!

The reduction of land usage and increased energy efficiency of a vegan world has big implications for food security. If we just shifted the cropland the US uses to feed cattle to plant crops for human consumption, we could feed an additional 190 million people! And, by growing all the world’s food directly for human consumption, we could increase available food calories by 70%. That amount could feed 4 billion more people—way more than the projected additional population of 2050. Clearly, a systematic reduction or elimination of animal agriculture will reduce land and water use and increase the world’s food security.

But, some people argue that some plant foods are environmentally worse than animals. Soy, a common ingredient of vegan foods, is one of the worst crops for the environment. In many cases it causes deforestation, waterway pollution, and damages to biodiversity. However, this argument is self-defeating, as most soy crops are fed to animals.

Out of all soy, over 75% is fed to livestock. Only 7% goes to humans, the rest going towards biofuels and tech. Soy is a damaging crop, but a vast majority goes to feed animals. So, just eating soybeans straight from the plant is kinder to the environment and more efficient than eating animals fed by soy.

Now that we’ve established that feed crops are unsustainable, what about areas where animals are farmed that can’t even grow human-edible crops? Much land that is currently used for livestock, like some pastures, are unsuitable for farming plants. Why, then, should we get rid of the animals?

There are a myriad of choices for a plot of land that can’t be used for crops. One can build residential areas to accommodate our rising population, make commercial or industrial complexes, or re-wild the area. Rewilding has a myriad of benefits: increasing carbon capture, biodiversity, and of course making our world a more beautiful place.

Animal agriculture is an inefficient use of our finite resources. Even the food chain demonstrates the effectiveness of going plant-based. But, systematic change towards a greener world needs help: from activists, lobbyists, and from consumers making more sustainable choices. Will you make the switch from knife to fork to create a kinder world?

Sierra Glassman is a recent high school graduate and Eat for the Earth summer 2022 intern. She has a passion for birds and has been accepted into UC Berkeley to study integrative biology starting Fall, 2022. She is spending her summer creating an educational video series for Eat for the Earth’s YouTube channel. During her brief time with the organization, she has researched and written three grants, had one approved (so far), created a plan for the series and an ad campaign, and is launching the first video today!

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