> the planet will continue to have multiple climate zones Yes, but large-scale crop production is not so easy to move. > it won't take a planet-wide crop fail

> the planet will continue to have multiple climate zones Yes, but large-scale crop production is not so easy to move. > it won't take a planet-wide crop failure Yes, by "planet-wide crop failure" I didn't mean that there won't be a harvest anywhere, just that production will drop low enough that there is no more surplus. I'm pretty sure that will be enough to destabilize our geopolitics, and it will be all downhill from there for quite a while.