There's reasonable enough relations between the US and the British for Brits t settle in the US. The ones who don't mind the 'liberal' views of the US and not being under British rule will do so, and be welcome (especially the white ones - damn racism). I'm going to disagree with you at least insofar as prominent historical figures go for the south exporting people to the north - I have had a very difficult time finding any people who moved from the south to the north, but rather have found several who moved from the north to the south. Now then, I do see the South exporting people - but to the west! So while you will see some leakage of people into the US, the main pattern will be to move westward. The Caribbean I agree. The Mainland, however, has enough 'human' climate that I think we'll see them go there. And if we're talking climate, I hardly think that Australia would be the preferred settlement region on that!