What if all whites returned to Europe?

[renaissance12]

Hey guys, already posted this on the Latin American section, but I'm curious about different viewpoints from all across the boards. What would the social, cultural and political ramifications be if whites from North America, Oceania, Siberia, South America, Cuba and South Africa went back to the lands of their ancestors? How would the locals react? Would there be good or tense relations? What kind of culture classes would occur?

There will be more space for the Chinese