Carbon 14 dating half life
Specimens which lived and died during a period of intense volcanism would appear older than they really are if they were dated using this technique.
The ratio can further be affected by C-14 production rates in the atmosphere, which in turn is affected by the amount of cosmic rays penetrating the earth's atmosphere.
This man-made fluctuation wasn't a natural occurrence, but it demonstrates the fact that fluctuation is possible and that a period of natural upheaval upon the earth could greatly affect the ratio.
Volcanoes spew out CO which could just as effectively decrease the ratio.
However, there is strong evidence which suggests that radioactive decay may have been greatly accelerated in the unobservable past.
We must also assume that the ratio of C-12 to C-14 in the atmosphere has remained constant throughout the unobservable past (so we can know what the ratio was at the time of the specimen's death).
C-12 is by far the most common isotope, while only about one in a trillion carbon atoms is C-14.
Carbon-14 has a half-life of 5,730 ± 40 years—, half the amount of the radioisotope present at any given time will undergo spontaneous disintegration during the succeeding 5,730 years.
Because carbon-14 decays at this constant rate, an estimate of the date at which an organism died can be made by measuring the amount of its residual radiocarbon.
This means there's been a steady increase in radiocarbon production (which would increase the ratio). God, the Father, sent His only Son to satisfy that judgment for those who believe in Him.
And finally, this dating scheme is controversial because the dates derived are often wildly inconsistent. Jesus, the creator and eternal Son of God, who lived a sinless life, loves us so much that He died for our sins, taking the punishment that we deserve, was buried, and rose from the dead according to the Bible.