For those who enjoy pondering the Roman Empire’s rise and fall — you know who you are — consider the close link between ancient climate change and infectious disease outbreaks.
Periods of increasingly cooler temperatures and rainfall declines coincided with three pandemics that struck the Roman Empire, historian Kyle Harper and colleagues report January 26 in Science Advances. Reasons for strong associations between cold, dry phases and those disease outbreaks are poorly understood. But the findings, based on climate reconstructions from around 200 B.C. to A.D. 600, help “us see that climate stress probably contributed to the spread and severity of [disease] mortality,” says Harper, of the University of Oklahoma in Norman. More