Tuesday, July 28, 2015

Will carbon emissions interfere with radiocarbon dating?

OMINOUS: Fossil fuel emissions are making carbon dating more difficult (Sarah Kaplan, WaPo).
Carbon dating had never been, and likely never again will be, quite so glamorous — or so controversial [as when dating the Shroud of Turin]. And, thanks to atmospheric changes caused by the burning of fossil fuels, it could become even more complicated.

That’s according to a new study in the Proceedings of the National Academy of Sciences published Monday. Physicist Heather D. Graven of Imperial College London found that carbon emissions from fossil fuels are artificially raising the carbon age of the atmosphere, making objects today seem older to a carbon dater. By 2050, new clothes could have the same radiocarbon date as something that’s ten centuries old.
You can read the new study here (but probably it's behind a subscription wall - I have an institutional subscription). The abstract is here.

If correct, this conclusion isn't very good news, but let's keep in mind that it is based on simulations, since there really isn't any way to conduct controlled, repeatable experiments for this type of question. Such simulations are far from infallible, so I think some degree of skepticism is warranted. We'll see.

Radiocarbon dating is an important, if sometimes less than straightforward, tool for historians. Some relevant posts are here, here, here (but see also here and links), and here (but follow the link at the bottom for follow-up posts).