We don’t have to reeducate most people though. Just those who produce food in bulk.
Also there’s the fact that we can transport large amounts of food around the globe from where they grow as things shift.
I think the worry is, among others, that the reduced outputs from the grain regions of the US, Canada, Argentina, Russia, China, India can’t easily be replaced.
Even if it can be replaced the geo-political turmoil would likely be severe.