It's the standard dating scheme used in archaeology and some areas of geology for material that is carbon dated. As mentioned on the wikipedia page that OP linked to, "present" is actually a standard date: January 1, 1950; chosen because material from later dates can not be reliably measured [using carbon dating] due to nuclear testing.
No that is when radioactive forms of carbon start to push us into a different situation with regards to radiocarbon dating. It is basically pre nuclear weapons and post now.
what about BCE (as in "Before Common Era"), i thought this was the pc way of expressing this in our post-religious world of tomorrow!? https://en.wikipedia.org/wiki/Common_era
> "present" is actually a standard date: January 1, 1950
which is an abuse of the English langauge, since "present" actually means "now." Scientists should not overload pre-existing English words to mean other things.
I would state the argument as follows: We should use the term "before nuclear testing", abbreviated as BNT. It is more precise than "before present", which will become more inaccurate over time, whereas "before nuclear testing" will always have the same meaning.
