Other corrections must be made to account for the proportion of throughout the biosphere (reservoir effects).
Additional complications come from the burning of fossil fuels such as coal and oil, and from the above-ground nuclear tests done in the 1950s and 1960s.
Atmospheric nuclear weapon tests almost doubled the concentration of concentrations in the neighbourhood of large cities are lower than the atmospheric average.
The development of radiocarbon dating has had a profound impact on archaeology.
In addition to permitting more accurate dating within archaeological sites than previous methods, it allows comparison of dates of events across great distances.
Animals eat the plants, and ultimately the radiocarbon is distributed throughout the biosphere.
The ratio of λ is a constant that depends on the particular isotope; for a given isotope it is equal to the reciprocal of the mean-life – i.e.
By contrast, methane created from petroleum showed no radiocarbon activity because of its age.