This is promising, but it does basically rely on human populations stabilizing fairly soon. Interestingly the most solid factors for that is women's education and rights and children's health care, that correlates most closely with reduced population growth (I mean, not many people would really want to pump out ten kids and watch six to eight of them die of childhood diseases, which was about the pre-industrial norm, given the choice - having two kids is the basic replacement number assuming they survive to adulthood).
Hydroponics plus desalination is kind of interesting, as then you could grow some crops on seriously non-arable land, although I don't recall ever seeing high-protein crops (such as legumes with associated nitrogen-fixing bacteria) grown hydroponically. In terms of total calories per land area IIRC potatoes are the big winners there, never seen hydroponic potatoes either.
Hydroponics plus desalination is kind of interesting, as then you could grow some crops on seriously non-arable land, although I don't recall ever seeing high-protein crops (such as legumes with associated nitrogen-fixing bacteria) grown hydroponically. In terms of total calories per land area IIRC potatoes are the big winners there, never seen hydroponic potatoes either.