This also has to be corrected for. Second, the ratio of C in the atmosphere at that time to be estimated, and so partial calibration of the “clock” is possible.Accordingly, carbon dating carefully applied to items from historical times can be useful.
The rate of decay of N in 5,730 years (plus or minus 40 years).The strength of the Earth's magnetic field affects the amount of cosmic rays entering the atmosphere.A stronger magnetic field deflects more cosmic rays away from the Earth.Also, the Genesis flood would have greatly upset the carbon balance.The flood buried a huge amount of carbon, which became coal, oil, etc., lowering the total C ratio in plants/animals/the atmosphere before the flood had to be lower than what it is now.Cosmic rays enter the earth's atmosphere in large numbers every day.
For example, every person is hit by about half a million cosmic rays every hour.
Overall, the energy of the Earth's magnetic field has been decreasing, so more C is being produced now than in the past.
This will make old things look older than they really are.
That is, they take up less than would be expected and so they test older than they really are.
Furthermore, different types of plants discriminate differently.
The carbon-14 atoms are always decaying, but they are being replaced by new carbon-14 atoms at a constant rate.