While an uncalibrated reading may be off by a factor of 10%-20%, calibration severely reduces that value.
Standard calibration curves are now used for more accurate readings.
This inconsistent amount of carbon-14 renders the test less accurate but opens up testing possibilities not available for older samples.
Carbon-14 dating can be used on objects ranging from a few hundred years old to 50,000 years old.
Libby and others (University of Chicago) devised a method of estimating the age of organic material based on the decay rate of carbon-14.
likely to detect the presence of C-14 in amounts less than about 100,000 dpm (0.05 µCi).
Low-level C-14 contamination cannot be easily detected with a G-M meter, and special precautions are needed to keep the work environment clean.
The effects expected are: We have already seen evidence it is happening, the polar ice caps are melting, flooding is a regular headline in the news around the world, and the weather is already showing signs of becoming eratic.