Sometimes accompanied with mentions of 420.(Search 420 for more information!
Anyway, you don't need to worry, BC/AD has not lost at all to the metric system or Kwanzaa, it is still very much what is used and recognized (but I haven't looked at any high school history books lately).
Dates in the Gregorian calendar in the Western world have always used the era designated in English as Anno Domini or Common Era, but over the millennia a wide variety of eras have been used with the Julian calendar.
Personally I always thought it was MORE culturally insensitive.
Archaeologists also use BP - before present - which is confusingly set as 1950.
Astronomers of course have the best solution - just count days.