White Europeans still have a variation in skin colour but they are typically a much lighter shade than "red' Amer-indians or "black" Africans. Truly, colour is only skin deep.
Exactly true. For people like myself who are of Greek heritage, we are often referred to as 'olive skinned'. While we are classified as 'white', clearly we are a shade darker than those from northern climates like the UK, Ireland or the Scandinavian countries.
And the primary difference is ultimately latitude and climate. Northerly climates are more overcast and colder, which denotes selective pressures would favor skin tones that absorb more light. While those in the Mediterranean areas would evolve to have slightly darker skin since sunlight is more prevalent.
Note that even among darker skinned individuals, there are wide variances as well. Clearly, those in the Indian subcontinent have a different shade versus those in Africa. And parts of Africa likely have variances among their populations as well. Asian countries also have variances as well. People in Japan versus those in Cambodia or Vietnam will have different skin tones.
A photographer in the UK did a nice collage of all the different skin tones she found. See following image:
Also a great example of why racism is so friggen stupid.