Effects of climate conditions on hunger...
I don't know if this is already planned, but it seems appropriate to me that extremes of climate would cause hunger to decay faster, and that various machines and constructions would change that. From the primitive (building a roof over an area makes it cooler) to the industrial (an electricity-guzzling air conditioner that makes the whole structure cooler), it could have a lot of effect on the way people build.
Above all, it would make the long-term consequences of industrialization more material. When heat waves or freak storms make people get hungry, they'll know why. Likewise, it makes the planet's climate zones more important, as building in the desert no longer simply means that food is harder to get -- working outside is exhausting!