Economic dynamics of the Early Roman Empire: Insights from lead pollution, coinage, weather, and war

This study examines the relationship between anthropogenic lead pollution recorded in Greenland ice cores and economic dynamics during the Pax Romana (27 BC–180 AD), a period of relative political, institutional and technological stability in the Early Roman Empire. Our findings reveal that approximately one-fourth of the annual variability in lead pollution during this period can be explained by summer temperatures, silver coin output, and warfare — three factors plausibly linked to fluctuations of the Empire’s economy. Using annual time-series analysis, we integrate high-resolution paleoclimatic, paleoenvironmental, and cliometric data to investigate short-run economic dynamics in an ancient society. Specifically, our results suggest that warmer summers, which likely boosted agricultural yields, were positively associated with increased economic activity. In contrast, higher production of silver coins and periods of warfare were associated with lower levels of lead emissions, suggesting that these factors were associated with periods of weaker aggregate economic activity. Our analysis also provides formal statistical support for the hypothesis that historical lead pollution levels contain valuable information about economic activity in ancient Europe, thereby corroborating a highly debated claim in the literature.