Radiocarbon dating curve is the key to unlocking the past and informing policy

Richard III skeleton

Through collaboration we've developed an internationally-recognised method for reliably dating items up to 50,000 years old.

Our statisticians helped produce the radiocarbon calibration curves IntCal04, IntCal09 and, most recently, IntCal13. The curves allow scientists and archaeologists to obtain precise age estimates for discoveries. IntCal09 was used to date the excavated bones of King Richard III (pictured) and mammoths preserved in Siberia.

The curves also reduce uncertainty about the timing of major events in the history and development of humans, plants and animals and the environments in which they lived.

Radiocarbon dating is possible because, while alive, plants, animals and humans absorb tiny amounts of radioactive carbon-14 from the atmosphere. When they die, absorption stops and the amount of carbon-14 begins to decrease in a predictable way as described by the law of radioactive decay.

But carbon-14 levels have fluctuated over time, so to allow accurate dating, an adjustment must be made using a calibration curve.

Because successful interpretation of radiocarbon dates can only be done with calibration, IntCal13 is vital for dating archaeological sites and past environmental change around the world. This makes IntCal13 an indispensable tool for the radiocarbon dating sector, a market estimated to be worth around £17.5m per year.

Developed by researchers from our School of Mathematics and Statistics and the CHRONO Centre at Queen's University Belfast, IntCal13 will provide reliable time-scales for both archaeologists and environmental scientists.

Those seeking to compare and combine large bodies of evidence, like members of the International Panel on Climate Change, will also benefit from the method.

IntCal curves are also key to the British Antarctic Survey’s advice to governments and policy makers on past climate, and are used by English Heritage to inform its advice on the management of archaeological and historic monuments.

Eric Wolff FRS, Science Leader (Chemistry and Past Climate), British Antarctic Survey, said: "Correct and consistent dating of past events in the palaeorecord is crucial to our ability to understand processes in the earth system, and therefore to verify and improve models of its future behaviour. In this sense the work of IntCal is one of the cornerstones that allows us to use the past to provide insights that can inform policy."

IntCal13 is the culmination of five years of research funded by the Natural Environment Research Council (NERC) and more than ten years of research by the teams at Sheffield and Queen's Universities.

Radiocarbon dating has been possible since the middle of the 20th century, but it is only because of improved statistical models such as those behind IntCal13 (and its predecessor IntCal09 – also funded by NERC) that scientists can now accurately date objects older than 14,000 years and up to 50,000 years old.

Image: The University of Leicester