P_02

Radiocarbon calibration: from bane to blessing

Bronk Ramsey C¹

¹University Of Oxford, United Kingdom

Temporal and spatial variation in radiocarbon in the atmosphere has been the subject of investigation from the first pioneering work of Libby and Arnold in the middle of last century.  However, as the precision of measurements has improved, now by almost two orders of magnitude, what constitutes a significant variation has also changed. Furthermore, through the development of other dating techniques applied to global records, it is possible to test degrees of variation over much longer timescales and with ever wider geographic coverage.  As knowledge has improved, the interpretation of radiocarbon measurements has had to be revised, often very significantly as with the first comprehensive calibration curves.  These re-evaluations, and the loss of chronological precision that comes with accurate calibration, have often been seen as an unfortunate drawback in the radiocarbon dating method.  However, ‘necessity is the mother of invention’ and these problems have stimulated extensive research in global radiocarbon records, in statistical methods for dealing with complex radiocarbon data, and in measurement methods.  This research has both provided a wealth of information useful for other scientific challenges, most notably the quantification of the global carbon cycle, but also enabled, in the right circumstances, measurement precision an order of magnitude better than if there had been no variation in atmospheric radiocarbon.  Challenges remain in many areas but, taking a long perspective, the research undertaken for radiocarbon calibration has, through its ingenuity and innovation, provided rich scientific dividends in both chronology and broader geoscience.