Droughts and conflicts during the late Roman period

Area of Science:

• Environmental History
• Climate Science
• Archaeology

Background:

• The collapse of Roman Britain (c. 410 CE) and the Western Roman Empire (476 CE) have complex, debated causes.
• Previous research has not fully integrated climate data with historical events to explain these declines.

Purpose of the Study:

• To investigate the role of climate variability, specifically summer droughts, in Roman societal instability and conflict.
• To establish a mechanistic model linking drought, resource scarcity, and societal collapse in agrarian societies.

Main Methods:

• Utilized tree ring-based climate reconstructions and historical documentary sources.
• Analyzed climate-conflict linkages across the Roman Empire (350-476 CE), with a case study on Roman Britain.

Main Results:

• A sequence of severe summer droughts (364-366 CE) correlated with harvest failures, food shortages, and the 'Barbarian Conspiracy' in Roman Britain.
• Found clear links between years of battles in the Roman Empire and preceding warm, dry summers.
• Observed anomalous coin hoarding and depopulation of settlements during drought periods.

Conclusions:

• Prolonged droughts are a significant driver of agrarian societal vulnerability.
• Climate variability, through harvest failures and food shortages, can lead to societal pressure, instability, and conflict, contributing to the decline of empires.