"Caucasian" is a stupid word, a hangover from daft pseudo-scientific racism in the nineteenth century.   

The Caucasus is a range of mountains on the far side of Europe, where it butts up against Iran and Iraq, where there are a few small countries whose variegated inhabitants don't get on too well with each other.

Calling "white" people "Caucasian" is akin to referring to "black" people as "Ethiopian", which was also done at that time - except it's even more bizarre. At least Ethiopia has a certain special status as the only part of Africa which had at that time successfully resisted colonial rule. Nothing equivalent to that for the Caucasus.

If it's important to people to have some pseudo-racial label, White and Black are probably the simplest.   How about Cro-Magnon to cover us all? Or indeed "of African descent", since that's where all our ancestors evidently came from.