Climate Change, Agricultural Yields and the Fall of the Roman Empire

Abstract

The Roman Empire fell at the end of the 5th century AD. Many potential drivers exist behind the decline of such a large nation that spanned Europe, one of them being climate change. It is hypothesised that the shift in climate and weather conditions caused agriculture to falter and produce less food. This would put pressure on the trade networks within the empire, contributing to its destabilization and eventual fall. Using the new Jugerum model, this research attempts to quantify this destabilization by simulating the climate conditions prevalent during the later centuries of the Empire. These simulated climate conditions are derived from the ERA20-CM database to create 6 separate 110-year climate scenarios. Using these scenarios, PCR-GLOBWB is used to model the hydrology for the Roman Empire. This serves as input for the Jugerum model, allowing it to simulate crop production for 4 different crop types. The production is then aggregated into a network based on ORBIS, and trade is simulated in this network to ensure that all demand can be met. The results of the model simulation suggest that the total amount of crops produced within the Roman Empire does not meaningfully change in between climate scenarios, but the allocation of crop land is affected. This is shown to have a negative effect on the stability of the simulated trade network, with the trade volumes showing an increase in year-on-year fluctuations.