Would the horse go through climate change?

Hey!!! I Live and ride in germany, and I have all my life!!! I have been to america once for a week. I am german american!! My parents might want to move back to georgia soon, and i have a horse here in germany. The weather in germany is chilly and cold and sometimes super hot. I was just wondering would it be a shock if i shipped my horse back? I would ship him to canada for quarantine, and then drive to georgia but would that be a shock to him with the climate?? Thanks so much!!! <3