The presence of bomb carbon in the earth's biosphere has enabled it to be used as a tracer to investigate the mechanics of carbon mixing and exchange processes.
Ellen Druffel has called this the silver lining in thermonuclear bomb testing.
Radiocarbon discrepancies due to volcanic CO2 emissions are a popular source of ammunition for fundamentalist viewpoints keen to present evidence to show that the radiocarbon method is somehow fundamentally flawed.
Since about 1890, the use of industrial and fossil fuels has resulted in large amounts of CO2 being emitted into the atmosphere.
Hans Suess (1955) discovered the industrial effect (also called after him) in the 1950's.
A number of researchers found that the activity they expected from material growing since 1890 AD was lower.
The effect of this has been to almost double the amount of C14 activity in terrestrial carbon bearing materials (Taylor, 1987).
Thus it was that 1890 wood was used as the modern radiocarbon standard, extrapolated for decay to 1950 AD.This apparent age of oceanic water is caused both by the delay in exchange rates between atmospheric CO2 and ocean bicarbonate, and the dilution effect caused by the mixing of surface waters with upwelled deep waters which are very old (Mangerud 1972).A reservoir correction must therefore be made to any conventional shell dates to account for this difference.A shellfish alive today in a lake within a limestone catchment, for instance, will yield a radiocarbon date which is excessively old.The reason for this anomaly is that the limestone, which is weathered and dissolved into bicarbonate, has no radioactive carbon.In such a case, it is very difficult to ascertain the precise reservoir difference and hence apply a correction to the measured radiocarbon age.