Fossil fuel emissions could soon start to cause headaches for archaeologists and paleontologists using radiocarbon dating to study artifacts. New research suggests the release of carbon-based gases into the atmosphere by vehicles and factories could alter radiocarbon measurements of ancient material.
Radiocarbon dating measures levels of carbon-14, a naturally radioactive form of the atom. This technique, first developed in the 1940's, determines the age of any organic material by measuring ratios between carbon-14 and nonradioactive atoms of the element.
Researchers stated that at current rates of atmospheric carbon emissions, so much error will have been introduced into radiocarbon measurements that by the year 2050, an item 1,000 years old would be indistinguishable from a brand-new sample. Researchers could begin seeing this effect as early as the year 2020, the study determined.
Carbon-14 atoms within organic material decline over time, allowing investigators to measure the age of a given artifact. Ancient organic remains, such as oil and coal, are so old, they are nearly devoid of carbon-14. As carbon emissions from human-based activities continue, concentrations of carbon-14 will decrease, as the radioactive atoms are diluted from the pollution and the radiocarbon "age" of the atmosphere is artificially raised.
"If we did any current measurements on new products, they will end up having the same fraction of radiocarbon to total carbon as something that's lost it over time due to decay. So if we just measure the fraction they'll look like they have the same age for radiocarbon dating," Heather Graven of Imperial College London, lead author of an article detailing the study, said.
This is not the first time in modern history in which human activities are altering levels of carbon-14 in relics. Carbon first began to dilute the marker material at the beginning of the Industrial Revolution, researchers state. Concentrations climbed once again during the 1950s and '60s as nuclear tests released the radioactive atoms into the environment. Today, concentrations of carbon-14 measure about the same as they did prior to the rise of industry.
Radiocarbon dating can not only measure the age of ashes from a fire, or a bone within a knife handle, but has even been used to detect art fraud. However, within just 35 years, Graven predicts a robe worn while an anonymous writer penned Beowulf would be indistinguishable in age from a T-shirt worn last weekend by a guy watching football.
"If we reduced fossil fuel emissions, it would be good news for radiocarbon dating," Graven said.
Study of how fossil fuel emissions affect radiocarbon dating was profiled in the Proceedings of the National Academy of Sciences.
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