The human diet is probably split into several major categories and I think a one size fits all solution is probably not forthcoming. The first category which m

The human diet is probably split into several major categories and I think a one size fits all solution is probably not forthcoming. The first category which makes up the bulk of our diet are caloric cereal crops, or starchy tubers. In the calorie category it's all about getting the most starch out of a given land area. All these permaculture, food forest idealists, conveniently don't talk much about calories. Starch is a pretty simple molecule/polymer, I wouldn't be surprised if we find a way to synthesize it from energy and hydrogen feedstock. Then there is protein/nitrogen sources, which today are obtained from animal and legume products. Legumes are undoubtedly more efficient than animal products but are unfortunately still pretty heavy land users. My guess is we'll be eating food fortified with precision fermented proteins pretty soon. Some of those proteins will be mixed with soy, and the synthetic starch and used to produce chicken/fish feed. And then finally there's the third category, vitamin and mineral containing foods (fresh greens, fruits, nuts etc). This is where "weeds" come in. I think in a lot of ways this is already pretty much solved by glasshouse/hydroponic cultivation and is already being practiced on a huge industrial scale. At the end of the day I don't think there's really a serious risk that climate change completely disrupts modern agriculture. Yes it will cause massive changes to the varieties, techniques, and distribution of what we grow but we'll be able to work around it.