I'm worried that we won't be able to support the population we have. Lower quality of life I can handle. Famine and starvation is frightening. I hate to say it, but we'll probably be ok in North America. The rest of the world, fuck.
Crop failures could happen at any moment, we're already seeing it to some extent. We pushed the global population to the point where a single event (Ukraine) is bad for global supply.