In contrast, from 1955 to 1963, atmospheric radiocarbon levels almost doubled.
The new method is based on the fact that over the past 60 years, environmental levels of radiocarbon have been significantly perturbed by mid-20th-century episodes of above-ground nuclear weapons testing.
Before the nuclear age, the amount of radiocarbon in the environment varied little in the span of a century.
Barring any future nuclear detonations, this method should continue to be useful for year-of-birth determinations for people born during the next 10 or 20 years.
Everyone born after that would be expected to have the same level of carbon-14 that prevailed before the nuclear testing era.
C and counting the amount of each) allows one to date the death of the once-living things.
Perhaps you have heard of Ice Man, a man living in the Alps who died and was entombed in glacial ice until recently when the ice moved and melted.
Unlike tooth enamel, soft tissues are constantly being made and remade during life.
Thus, their radiocarbon levels mirror those in the changing environment.
Now, new applications for the technique are emerging in forensics, thanks to research funded by NIJ and other organizations.
In recent years, forensic scientists have started to apply carbon-14 dating to cases in which law enforcement agencies hope to find out the age of a skeleton or other unidentified human remains.
Thus, pupal case radiocarbon content would serve as a decay-resistant proxy for the tissues, yielding the year of death.