Next, why should you be concerned "if" the population of Whites is declining? Well for one, because Whites are the best kinds of people. If you don't believe that, somebody around here started a thread called, "Is the White species superior?" I suggest you look it up and read it. You don't want there to be fewer of what is better. Also, if the number of Whites was to decline, it might not be so bad if they weren't being replaced with non-whites.
But all that aside, you are asking the wrong question. It isn't if the number of Whites was to decline, how bad would it be. The question you should be asking yourself is that if the population of non-whites was rising, which it is, why is that a bad thing.
I guess that settles that. Bigot.