Volcanoes spew out CO which could just as effectively decrease the ratio.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.Another limitation is that this technique can only be applied to organic material such as bone, flesh, or wood. Carbon Dating - The Premise Carbon dating is a dating technique predicated upon three things: Carbon Dating - The Controversy Carbon dating is controversial for a couple of reasons.
We also know that the ratio decreased during the industrial revolution due to the dramatic increase of CO produced by factories.
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.
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).
And yet we know that "radiocarbon is forming 28-37% faster than it is decaying," which means it hasn't yet reached equilibrium, which means the ratio is higher today than it was in the unobservable past.
It takes about 5,730 years for half of a sample of radiocarbon to decay back into nitrogen.
It takes another 5,730 for half of the remainder to decay, and then another 5,730 for half of what's left then to decay and so on.
The rate of decay depends upon the number of atoms you have.
This means that as more of these atoms decay you have a lower rate of radioactive decay. If you roll a one, then that object decays and turns into something else.
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.
The amount of cosmic rays penetrating the earth's atmosphere is itself affected by things like the earth's magnetic field which deflects cosmic rays.
When a creature dies, it ceases to consume more radiocarbon while the C-14 already in its body continues to decay back into nitrogen.