Plague and Climate in the Collapse of an Ancient World-System: Afro-Eurasia, 2nd Century CE

This article examines the potential role of the Antonine Plague (165–180 CE) and climate change in the mid-2nd-century collapse of the Afro-Eurasian world-system. Following the model proposed by Gills and Frank, the world-system cycles between phases of integration (A) and disintegration (B). Integrative phases are marked by increasingly complex exchanges of goods, services, information, and populations, which enhance connectivity and intensify the circulation of matter and energy. Yet, this very complexity, while driving growth and expansion, also generates systemic vulnerabilities. The plague and climate change are examined here as critical shocks that triggered the shift from an A phase to a B phase, destabilizing interconnected regions such as the Roman Empire in the West and the Han Dynasty in China. The demographic losses and logistical strains of the pandemic eroded the integrative structures underpinning Afro-Eurasian connectivity, creating conditions for prolonged disintegration. These developments are further situated within the broader history of the Silk Roads, whose role in fostering transcontinental connections had reached a peak in the centuries preceding the crisis. The analysis underscores how pandemics like the Antonine Plague, together with episodes of abrupt climate change, can act as decisive agents in the disintegration phases of world-systems, reshaping the trajectories of complex societies and accelerating the collapse of established networks.