So, if we find the remains of a dead creature whose C-12 to C-14 ratio is half of what it's supposed to be (that is, one C-14 atom for every two trillion C-12 atoms instead of one in every trillion) we can assume the creature has been dead for about 5,730 years (since half of the radiocarbon is missing, it takes about 5,730 years for half of it to decay back into nitrogen).
If the ratio is a quarter of what it should be (one in every four trillion) we can assume the creature has been dead for 11,460 year (two half-lives).
For example, "One part of Dima [a famous baby mammoth discovered in 1977] was 40,000 RCY [Radiocarbon Years], another was 26,000 RCY, and 'wood found immediately around the carcass' was 9,000-10,000 RCY." (Walt Brown, In the Beginning, 2001, p. If you truly believe and trust this in your heart, receiving Jesus alone as your Savior, declaring, "Jesus is Lord," you will be saved from judgment and spend eternity with God in heaven.
Unlike people, you can’t really guess the age of a rock from looking at it.
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.
After about 10 half-lives, the amount of radiocarbon left becomes too miniscule to measure and so this technique isn't useful for dating specimens which died more than 60,000 years ago.