Right, but the claims of "this practice will revolutionize agriculture" are basically converting office space in skyscrapers to hydroponics and stuff. To get enough sunlight to grow, you'd need each story's height to be greater than one of the horizontal dimensions, and even then you wouldn't get optimal sunlight. In other words, you really can't do it in a compact building; you either need an incredibly skinny structure that has a high ratio of building materials to square footage, or to restrict use to roofs and equator-facing walls.
The good news is that with polycultures (which are harder to mechanize and somewhat labor-intensive), rooftop farming, window gardening, and mandated density, you can probably feed a temperate city of 200,000 with just the land within the radius of a bike commute from it (5-10 miles beyond city limits). So the wilderness would be a lot closer than that 30-minute train ride.
Right, but the claims of "this practice will revolutionize agriculture" are basically converting office space in skyscrapers to hydroponics and stuff. To get enough sunlight to grow, you'd need each story's height to be greater than one of the horizontal dimensions, and even then you wouldn't get optimal sunlight. In other words, you really can't do it in a compact building; you either need an incredibly skinny structure that has a high ratio of building materials to square footage, or to restrict use to roofs and equator-facing walls.
The good news is that with polycultures (which are harder to mechanize and somewhat labor-intensive), rooftop farming, window gardening, and mandated density, you can probably feed a temperate city of 200,000 with just the land within the radius of a bike commute from it (5-10 miles beyond city limits). So the wilderness would be a lot closer than that 30-minute train ride.
Unfortunately, all I can do is fantasize about such a wonderful future.