In case of discrepancy in such a fundamental assumption, the end results might be flawed.► With the advancement of nuclear reactors and weapons, it is possible that the amount of carbon-14 has changed in the recent years, specially carbon data from the 1950s and 1960s are questionable.
Radiocarbon Basics Carbon comes in three “varieties” or isotopes: C is 5,730 years.
Because carbon is expected to be thoroughly mixed throughout the biosphere, atmosphere, and oceans, living organisms (which continually “take in” carbon throughout their lifetimes) are expected to have the same C in their bodies begins to decrease.
The most common form of carbon in the atmosphere is carbon-12, which is a stable isotope of carbon.
An unstable form of carbon isotope, carbon-14, also known as radiocarbon, is formed when cosmic rays hit atoms in the upper atmosphere of the earth.
There are calibration charts as well to account for the change in the amount of carbon-14 content in the atmosphere over the years to diminish errors.