Records of the economic history of the Roman empire are scarce, but scientists have found a different way to measure the activity of Romans through ice cores. Taken from Greenland, the ice cores show how ancient Roman economy fared through times of peace, war, plague, and unrest.
This builds on a previous study done in the 90s.
Lead Pollution In Ice Cores
A team of researchers that included scientists, archeologists, and economists from the Desert Research Institute, University of Oxford, and the Norwegian Institute for Air Research published a study in the Proceedings of the National Academy of Sciences showing how ice cores can be used to study the Roman empire.
Ice cores taken from Greenland allowed the research team to gather data from 1,235 BC during the late Iron Age to the early Middle Ages around 1,257 AD. The accurately dated measurements found that lead pollution in the ice cores show the history of the Roman empire as events impacted the economy of the empire.
Researchers used a study from the mid-1990s which used 18 measurements in the period between 1,110 BC and AD 800. This new study follows the same time period but uses 21,000 measurements to create a record for the time period.
Ice cores can be difficult to come across in Greenland. It can take three to four years to drill into the bedrock and get to the cores. Researchers in this study were able to use a core that had to be abandoned after a drill got stuck at the 6,500-foot level, scientists used a 1,400-foot section of the core.
This core contained 40,000 years of annual snowfalls. It was then cut into rods just over three feet long then were melted from the bottom. The ice was melted at the rate of two inches per minute. Lead quantity was measured using mass spectrometers.
Roman prosperity is tied to lead because it was used for making water pipes and sheathing for boats. Romans made their standard coin, the denarius, out of silver and silver occurs in lead ores. Separating the silver from lead requires high temperatures which pumped lead into the atmosphere.
Ancient Roman History In Ice Cores
Scientists show that during times of peace, lead pollution from the Roman empire rose. This was during the period of Pax Romana between 27 BC and 180 A.D. There were drops in the level of lead after this period due to civil wars. Other events that caused a notable drop in lead production include the Antonine plague of 165-180 A.D., and the Cyprian plague 250-270 A.D.
The lowest point of lead emissions in the ice core was found to be during the Imperial Crisis of 235 to 284 A.D. During this time, there were barbarian invasions, the Cyprian plague, and internal problems within the empire.
In order to measure the Roman empire's economy, historians have only made assumptions since no records exist from the time.