A U.S. focused take from 2017: https://cliffmass.blogspot.com/2017/02/global-warming-will-b...

It depends on what model you believe will occur. If you believe in cyclic climate changes, then the old "green" regions will come back. If that's the case, the fertile crescent & old roman grow areas (North Africa) & American Southwest will have a greening.

Another factor that has been observed is the changes in the jetstreams. This past winter there were Polar vortexes leading to cold temperatures. Europe was recently hit with an Equatorial vortex leading to a heat wave.