• Redjard@lemmy.dbzer0.com
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    11 months ago

    On earth we have a land shortage. If you grow animal feed, that could have also been a foodcrop. In terms of land efficiency, meat is an order of magnitude less efficient.

    • SupraMario@lemmy.world
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      11 months ago

      We do not grow crops for just animal feed, the majority of what they consume is waste byproducts from what you are able to consume. It’s around 85% of their diet. So unless you have a way to all of a sudden eat stalks or roots or leaves and grass, it’s wasted if not feed to livestock.

      • Redjard@lemmy.dbzer0.com
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        11 months ago

        I’ll try to take a more nuanced and in depth look.

        As a start, I’m relatively sure the main use of a large chunk of agricultural land is solely food production. A cursory search gives data like this image
        global land use
        from this page.
        It’s reasonable to assume some of the plant waste of food crops feeds some of the livestock, but if that much land is exclusively used for animals it would seem reasonable we could at least double the human plant food production with a reduced animal portion in that land use.
        From a pure energy efficiency perspective animals are around 10%, so if you take half of produced plant calories and use them for animals, that will result in 10x fewer calories of animal products than the other half of the plants. This lines up with the energy spread by end human food product, which seems to be something like this:
        this is a shitty image link, that will probably break in the future. sry

        By the raw numbers and that coarse approach we expect 75% ⸱ 10% : 25% ≈ 1:3.3, the actual data seems to be slightly worse at 1:4.

        So it seems to me we are using something like 25% of the land area to produce 80% of the food, just by not passing it through animals. And if you are right then some of the animal calories are even supplemented with the plant waste of those 25%.

        The raw energy approach is actually quite a good approach by now, because we can use technology to transition most things into each other. You can pass plant waste into animals and loose 90% of the energy, or convert cellulose into (digestible) sugar and get the full energy. Or use it for other things that take energy like drug production. Using the plant waste on animals still brings that opportunity cost that means more land is used in other places to get the cellulose for those alternative uses, or to produce sugar the old fashioned way from more dedicated crops.

        Traditionally you had land that you could not use for agriculture but could use to graze goats, you had plant material you could not use for anything but feeding animals. Animals were our bioreactors to transform that material or land into usable products. Now we have better chains of use.

        The energy approach will finally be complete when we can turn plant material straight into animal products, with methods like lab grown meat or artificial milk, but we are not there yet. When we are, the energy balance of those should be close to that of plants and this entire problem simplifies greatly.

        • commie@lemmy.dbzer0.com
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          11 months ago

          much of the waste that is fed to animals does not have a better use, as you are suggesting. for instance, soycake. no one wants to eat that, but it’s high protein. giving it to animals conserves resources.

        • commie@lemmy.dbzer0.com
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          11 months ago

          The raw energy approach is actually quite a good approach by now, because we can use technology to transition most things into each other.

          this assumes some sort of centralized economy, instead of letting farmers give wasted apples to their neighbors horses or whatever.

        • commie@lemmy.dbzer0.com
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          11 months ago

          much of the land that is attributed to animal agriculture is grazing land, and is not suitable for growing crops.