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This all changed in the 1940s when US chemist Willard Libby discovered that carbon-14, a radioactive isotope, could be used to date organic compounds.
– 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.
If there are no steps to reduce emissions, then by 2050 the atmosphere will have a signature of what carbon ratios were 1,000 years ago.
By 2100, just one human lifetime away, the atmospheric clock will have been turned back to the era of Imperial Rome.
Their recent analysis of sediment from the largest freshwater lake in northeast China showed that its carbon clock stopped ticking as early as 30,000 years ago, or nearly half as long as was hitherto thought.
As scientists who study earth’s (relatively) modern history rely on this measurement tool to place their findings in the correct time period, the discovery that it is unreliable could put some in a quandary.But Heather Graven, a lecturer in climate physics and Earth observation at Imperial College London, reports in the US journal Proceedings of the National Academy of Sciences that by 2020, as the fossil fuel emissions mount up, the fraction of carbon-14 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-14 has decayed.This made me realise that fossil fuel emissions are likely to have an impact on these various uses for radiocarbon.Radiocarbon dating, which is used to calculate the age of certain organic materials, has been found to be unreliable, and sometimes wildly so - a discovery that could upset previous studies on climate change, scientists from China and Germany said in a new paper.“Thus it is necessary to pay [special] attention when using such old carbon data for palaeoclimatic or archaeological interpretations," they added.