Since the 1940s, scientists have used carbon dating to determine the age of fossils, identify vintages of wine and whiskey, and explore other organic artifacts like wood and ivory. The technique involves comparing the level of one kind of carbon atom—one that decays over time—with the level of another, more stable kind of carbon atom.
The approach was a sensation when it was introduced. The chemist who developed carbon dating, Willard Libby, won the Nobel Prize for his work. “Seldom has a single discovery in chemistry had such an impact on the thinking in so many fields of human endeavour,” one of Libby's colleagues wrote at the time, according to the Nobel Foundation.
Today, carbon dating is used so widely as to be taken for granted. Scientists across countless disciplines rely on it to date objects that are tens of thousands of years old.
That may soon change.
An analysis by Heather Graven, a climate-physics researcher at Imperial College London, finds that today's rate of fossil-fuel emissions is skewing the ratio of carbon that scientists use to determine an object's age. Combustion of fossil fuels is “diluting the fraction of atmospheric carbon dioxide containing radiocarbon,” Graven told Environmental Research Web. “This is making the atmosphere appear as though it has ‘aged,’ or lost radiocarbon by radioactive decay occurring over time.”