Estimating the prevalance of post-agricultural population declines through the global radiocarbon record

Joe Roe and Martin Hinz

Paper presented at World Neolithic Congress, Şanlıurfa, 4–8th November 2024, 2024.

Abstract

“Boom and bust” population dynamics are inferred to have followed the emergence or introduction of agriculture in several parts of the world. However, it is not currently understood whether this trend is intrinsic to prehistoric agriculture or contingent on other factors. Here we show how two large recently-available open archaeological datasets—XRONOS and ArchaeoGLOBE—can extend the geographic scope of previous analyses and reach an estimate of the global prevalence of post-agricultural population declines. XRONOS is a global database of radiocarbon dates and other chronometric information, which can (with several caveats) be taken as a population proxy. ArchaeoGLOBE contains estimates of prehistoric and historic land use in different regions based on an expert consensus model. Combining these sources provides a measure of demographic development relative to regional agricultural onset, on a (near-)global scale.

Our preliminary results show evidence of post-agricultural population declines in multiple discontiguous regions, in line with previous findings. However, they are not seen everywhere, and where they are the magnitude and temporality of the trend varies significantly. We suggest that this variance indicates that the “boom and bust” dynamic must be contigent on other, local factors, and offer some tentative indications of what these might be. We also discuss the limitations of this methodology—in particular the uneven coverage and quality of the global radiocarbon record, the lack of purely empirical estimates of agricultural onset for many regions, and reliance on aggregated radiocarbon data as a single demographic proxy—and suggest some ways it could be refined in future work.