> https://www.ipcc.ch/report/ar6/syr/

>> Have they modeled all the different plausible crops and agricultural techniques, which regional environmental conditions they're most suited for, and the transitions between them based on regional climate change effects?

> Seems so.

I'm not seeing it. I'm assuming you mean page 16 of the "Summary for Policymakers," but all that has is a unreadable map of "Maize Yield" projections with the disclaimer:

> Projected regional impacts reflect biophysical responses to changing temperature, precipitation, solar radiation, humidity, wind, and CO2 enhancement of growth and water retention in currently cultivated areas. Models assume that irrigated areas are not water-limited. Models do not represent pests, diseases, future agro-technological changes and some extreme climate responses.

So it sounds like they are not accounting for things like changes between crops or changing which areas are cultivated, which could be pretty significant. For instance: their tiny map shows the cultivated area in Canada remaining unchanged, but if you're looking at total world agricultural yield of a future warmer planet, it seems like you would have account for more Canadian land becoming arable and agriculture spreading further north.

> "Extremely" is a big word. Agricultural yields depend on the weather. A population of 9-10 billion will not be sustained by vertical farms maintained in a synthetic climate.

Which is not the way I (or anyone reasonable) would think people would adapt. Instead of the software-engineer techno-fetishist fantasy of "vertical farms", I would think the adaptations would consist of things like:

1. Creating new farms in areas where the climate is currently too cold for productive agriculture,

2. Switching to different crops or different varieties that are hardier against heat and drought or otherwise yield more calories (per whatever limiting factor),

3. Switching to different irrigation techniques that may be more water-efficient,

4. etc.