You should see an increase in your wage when the minimum goes to $15. A rising tide lifts all boats. Inflation is virtually zero, so rising wages are a good thing for the vast majority of wage and salary earning employees.
I think GP is worried this may not be the case, and he would lose purchasing power.
Nothing may happen, but I think we'll have to wait and see if this is the case or not.
I think the largest pay bump I've ever seen in a year was right at 2% or possibly even less.