War, Food, Climate Change, and the Decline of the Roman Empire

Over the past decade, several publications, amongst which most prominently the monograph published by Kyle Harper in 2017, have argued that climate change was a determining factor in the rise and decline of the Roman Empire. This article offers a critique of these studies, observing that they lack a clear analytical model and misleadingly represent climate change as consisting of uniform climatic eras, ignoring chronological and geographical variability. Moreover, it is argued that both the biology of arable crops and the societal aspects of agriculture offer a wide scope for adaptation. Furthermore, Roman politics or warfare in the third and fourth century do not show an increased weakness of the food supply, nor did the Nile floods have a major impact on events outside Egypt. Regional case-studies show that changes in landscape and settlement patterns are more often caused by societal developments than by climatic factors. Finally, the economic and demographic decline in the western half of the empire in the third and fourth century (while North Africa and the East continued to prosper) is linked to the declining ability of political and societal mechanisms to deal with ever-present harvest shocks. While climate change is not denied, societal factors are argued to have had a far greater impact on the fate of the Roman Empire.