One thing that is likely should the global cooling prove accurate is that the temperate zone and rainfall will shift south wrt North America. For example, some arid lands in Texas, New Mexico, Arizona and California could could bloom again into the rich grasslands they were as recent as the late 1800s and early 1900s. When I was a kid in the 1950s, I remember old timers describing how the landscape was lush dryland prairie instead of the moonscape it is now. Perhaps the desert of today will be the bread basket of tomorrow?
About a 500 mile shift for grow zone conditions?