Global environmental history is currently being enriched by troves of new data, and new models of environmental variability and human impact. Earth scientists are rapidly expanding historians’ knowledge of the paleoclimate through the recovery and analysis of climate proxies such as ice cores, tree rings, stalagmites, and marine and lake sediments. Further, archaeologists and anthropologists are using novel techniques and methods to study the history of health and disease, as revealed through examination of bones and paleomolecular evidence. These possibilities open the way for historians to participate in a conversation about the long history of environmental change and human response. This essay considers how one of the most classic of all historical questions–the fall of the Roman Empire–can receive an answer enriched by new knowledge about the role of environmental change.