I’ve periodically written about space colonization. (No, I am not obsessed about space. I can quit thinking about it any time I want to.) While doing that highly-important task of dinking around on the Internet, I came across this Twitter thread
The author, Dr. Sarah Taber, is an expert in agriculture, and does a lot of work in support of greenhouses and other agricultural endeavors. She was talking to somebody about how a vegetarian diet is more sustainable for the Earth. Perhaps surprisingly, she’s not in support of that. Some key points she makes:
1) Many human societies (Bedouin, Mongols, Maasai, Inuit) have all or very high meat diets.
2) Many of the early human societies that didn’t eat a lot of meat (The Ganges valley, ancient Egypt, China, much of early Europe) had two things in common:
a. Lots of rain
b. Hierarchical societies that could enforce a low-meat diet
3) Humans can only eat a relatively small part of a plant. We need seeds and soft leaves. As she says, “we eat straw, we’ll poop straw” without getting any nourishment from it.
4) Large parts of the world, to include the current lettuce capital of the USA, Arizona, naturally only support “scrub plants.” We can’t eat them, and the only way to get what we can eat to grow there is to irrigate the hell out of the place.
5) Cows and other animals with multiple stomachs can, on the other hand, eat these plants just fine. All you need for cows is drinking water.
Then the good doctor does the math. 10 cows could graze on 73 acres of land and consume about 67,000 gallons of water a year. To get food crops out of the same chunk of land, you’d need 79 MILLION gallons of water. Now, it’s true that you can feed more people on 73 acres of crops then you can on 10 cows, but only if you’ve got the water. So, in dry areas, it makes sense to let cows graze, and in wet areas one grows crops.
Now, let’s tie this to space. It’s traditional to assume that space colonists will eat only plants. But water is heavy, and even the best recycling system will have some losses. I suspect, therefore, that at some scale of agriculture it would not make sense to grow plants for protein. It would be better to raise animals – especially animals that can eat the stalks and shoots of plants we can’t.This entry was originally posted at https://chris-gerrib.dreamwidth.org/697516.html. Please comment there using OpenID.