Advances in radiocarbon dating could mean historical events haven't been recorded accurately

A study published in Science Advances on March 18 explored how variations in carbon levels in different geographical regions may mean that the calibration curve from the Northern Hemisphere is not appropriate for radiocarbon dating in the Mediterranean.

Since the 1960s, scientists have used a single calibration curve that was constructed from known-age wood found in central to northern Europe and North America. However, measurements of known-age wood from recent decades and different geographical regions have shown small offsets. This means other factors like growing seasons might affect levels of Carbon-14 more than scientists previously appreciated.

In this study the researchers report positive and negative Carbon-14 offset intervals for the Mediterranean which correspond to reversals and plateaus in atmospheric radiocarbon levels.

As measurements used in radiocarbon dating become more precise, historic events can be more accurately recorded. For example, scientists have long debated whether the date of the Thera (Santorini) volcanic eruption was in the mid–16th century BCE or later in the 17th century BCE. Using the revised calibration curve and appropriate offsets, these authors argue that it was more likely in the later 17th century BCE.

The discovery of these positive and negative Carbon-14 offsets have led these researchers to realize that a high-resolution Carbon-14 time series is required for accurate dating of the Mediterranean region. No single static adjustment will be satisfactory. Greater temporal and spatial resolution of seasonal variations is needed, to ensure accurate, precise measurements.