I think about this once in a while too, and then I remember that a bunch of German Nazis came out of the woodwork when just a million Syrians were admitted as war refugees. Whether northern countries accept more people or not, migration out of the tropics due to uninhabitable climate is coming.
Until the heat is everywhere and there is no place to run to, at which point things get ugly real fast.
I'm still for helping those in need, we have the resources to make a whole lot of lives better here.