Carbon dating uncertainty
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Radiocarbon dating is a key tool archaeologists use to determine the age of plants and objects made with organic material. But new research shows that commonly accepted radiocarbon dating standards can miss the mark -- calling into question historical timelines. Archaeologist Sturt Manning and colleagues have revealed variations in the radiocarbon cycle at certain periods of time, affecting frequently cited standards used in archaeological and historical research relevant to the southern Levant region, which includes Israel, southern Jordan and Egypt. These variations, or offsets, of up to 20 years in the calibration of precise radiocarbon dating could be related to climatic conditions.
New study warns that rising CO 2 levels from the burning of fossil fuels will undermine the precision with which once-living things can now be scientifically dated. LONDON, 24 July, — Climate change driven by increasing levels of atmospheric carbon dioxide will not just damage the health of the planet. A UK scientist now warns that it will also make life increasingly difficult for archaeologists, forensic scientists, art experts, fraud and forgery detectives, and people who detect ivory poachers.
Forensic scientists exhuming a skeleton, Egyptologists investigating an ancient tomb, and fraud detectives concerned with suspected forgeries of Renaissance paintings could still possibly make allowances for that. Radiocarbon dating is a year-old technique now used with increasing precision to date anything once alive from the last 50, years.
It exploits the natural ratio of two isotopes of carbon in the atmosphere. But Heather Graven, a lecturer in climate physics and Earth observation at Imperial College Londonreports in the US journal Proceedings of the National Academy of Sciences that byas the fossil fuel emissions mount up, the fraction of carbon in the atmosphere could drop to such a level that carbon-dating could become increasingly uncertain.
Fossil fuels are reservoirs of carbon from plants and algae that died so long ago that all the carbon has decayed. When carbon dioxide exhausts from combustion engines reach the atmosphere, they increase the levels of non-radioactive carbon, artificially ageing the atmosphere and, accordingly the new growths that exploit the atmospheric carbon. If there are no steps to reduce emissions, then by the atmosphere will have a ature of what carbon ratios were 1, years ago.
Byjust one human lifetime away, the atmospheric clock will have been turned back to the era of Imperial Rome. That means that a freshly-dead dung beetle that falls into an Egyptian tomb dating from the reign of Cleopatra would have the same radiocarbon age as the scarab that was trapped in the tomb under the sarcophagus 20 centuries ago. It also could, for instance, mean that border officials may not be able to distinguish museum collection ivory from illegally-poached elephant tusks, that fraud officers will not be able to confirm the age of costly single malt whisky or vintage claret, and that Jewish and Christian scholars may no longer be able to date important historic sources such as the Dead Sea Scrolls, or resolve doubts about the much-contested provenance of iconic relics such as the Shroud of Turin.
This made me realise that fossil fuel emissions are likely to have an impact on these various uses for radiocarbon. Climate News Network is a free and objective service publishing a daily news story on climate and energy issues.
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