ERL." href="http://images.iop.org/objects/erw/news/12/3/74/pic1.jpg">Decision tree
But the injection of fossil fuels into the atmosphere could cause problems with the calculations, by diluting 14C levels, in what’s often known as the Suess effect. Oil, coal and gas contain almost no 14C as they take many millions of years to form whilst 14C has a half-life of 5370 years.
With that in mind, Peter Köhler of the Alfred Wegener Institute in Germany modelled future emission scenarios, finding that considering 13C and 14C Suess effects in tandem could help avoid future confusion in radiocarbon dating results.
The Suess effect could lead to a scenario where past and future radiocarbon signatures are similar. Scientists believe that from the year 2050 fresh organic material might have the same 14C/12C ratio as samples that date back to 1050 AD. Fortunately, monitoring the level of 13C in tandem with the level of 14C could highlight the risk of such an ambiguity in future radiocarbon dating studies.
Köhler examined a range of representative concentration pathway (RCP) emissions scenarios to the year 2500. His modelling work revealed that when 13C concentrations, which are also influenced by fossil-fuel emissions under the 13C Suess effect, are taken into consideration, the output warns of scenarios where radiocarbon dating is likely to be affected.
"Compiling the raw data necessary to run the simulations was a big challenge," Köhler told environmentalresearchweb. "But according to the analysis we can use 13C for most carbon reservoirs to see if [results] have been affected by fossil-fuel emissions."
To help archaeologists and other users of radiocarbon dating disentangle past and future carbon-cycle changes, Köhler provides a decision tree. His model also accounts for several carbon dioxide reduction mechanisms, including carbon capture and storage.
Full details on the work, including projected changes in 13C levels, can be found in Environmental Research Letters (ERL).
Related links
- Using the Suess effect on the stable carbon isotope to distinguish the future from the past in radiocarbon Peter Köhler 2016 Environ. Res. Lett. 11 124016
- ERL
- Peter Köhler, Alfred Wegener Institute