There's "sustains the land," which is food that can be grown this way indefinitely, which is what most people mean when they say "sustainable agriculture." To be more specific, "meeting society's present food and textile needs, without compromising the ability for current or future generations to meet their needs."
You're saying sustainable as in "can sustain the future diets of 10 billion people."
They don't map 1:1.
TBH I think you're right. "Sustainable agriculture" isn't scalable to 2050 populations.
https://www.independent.co.uk/news/world/americas/the-good-l...
They are successful but are not capable of replacing 100% of the grocery needs. And vegetables only appear in the summer and can be subject to infestations or random die offs... although there is significant canning that takes place throughout the summer for the winter months. Growing a diverse amount vegetables to support 25-50 people is surprisingly more complex than raising livestock (unless you just want to eat lots of zucchini and squash ;-).
However, there are many well documented small co-ops in Portland that I can refer you to if you want to ask them questions. These are very small farms, and in many cases people buy their shares of well in advance, and some have even become store-fronts rather than pickups.
Here are examples of places within a 15 minute drive of where I live:
When I used to eat meat I would buy half a cow with some friends friends. You could go visit the cow throughout the year:
https://www.foodbevg.com/US/Scappoose/393417489771/All-Natur...
This place exploded in popularity in the past 7 years. It used to be two guys and you would order chickens months in advance and pick them up a day after the slaughter, now I can just walk into their store and they have a growing staff:
https://www.marionacres.com/order
Similarly:
https://www.kookoolanfarms.com/
This dairy was a kickstarter, and I get milk, cream, and eggs from them year round, its fantastic.
Lastly, Sauvie Island just outside portland has an enormous farm community where half of the year one can purchase all manner of fruits vegetables through multiple farmers market stands.
Again though: it is only for part of the year, year round veggies are damn hard without large industrial apparatus. Unless you like pickled things.
It can be done, but it takes a village. Seriously.
Surprising to me that year-round veggies is so hard even with modern methods/greenhouses.
You are correct: it is not so hard with modern methods, but none of the small communities I know of (15-50 people) have invested in a greenhouse of sufficient size. And even the local farms here don't have greenhouses, not that I am aware of. That seems odd to me, perhaps I am missing something because that seems unlikely now that I think about it...
Based on my travels to other countries, local farmers markets are simply called "markets" and there is nothing unusual about them. In the USA, small local markets and co-ops are a fringe thing because we are fed almost entirely by industrial farming through vast supply chains that terminate at enormous multi-purpose grocery stores.
I may have a few facts wrong, but this consolidation started after WWII, and local food co-ops were considered liberal operations because it was "liberal hippies" who were opposed to the industrialization of food.
Seeing extremely far right subsets embracing what has generally been considered far left behavior is just amusing.
Hope this clarifies!
I recently had a lengthy discussion with some friends about their support of a solidary organic farm, where you pay a flat fee per month and get a box of whatever they have in that week. It's really hard for most people to understand that things like these are not sustainable and that it's purely a luxury product. Terms like "organic", "no GMO", "local" sound sustainable as you imagine going back to "the good old days", but it's just impossible to feed the world. Even after I quoted some facts about the needed land usage for organic, it was not really possible to convince them, that it's not sustainable.
If anybody has some good articles / studies about sustainable farming for the future, I would love to read them.