The manuscript by Skinner et al. presents a unique and useful data compilation of ocean-atmosphere radiocarbon age offset (B-Atm) across the last deglaciation. The presented global average B-Atm represents a new benchmark for modelling studies seeking to constrain the ocean's role in past atmospheric CO2 change, and seeking closure of the global radiocarbon cycle. The latter is important for constraining the carbon cycle evolution over the last deglaciation (which remains to be quantitatively accounted for), as well as the history of the geodynamo and solar activity.