Managing the risk of climatic variability in late prehistoric northern Chile

► Late prehistoric northern Chile presented significant ecological and social risks. ► Settlement patterns, ceramics, and rock art reveal risk management strategies. ► Communities coped with drought through trade, diversification, and extensification. ► Risk of food shortfalls exacerbated inter-group raiding and intra-community strife. ► Defensive sites, alliances, and ritualized trade ameliorated the risk of conflict. The concept of risk management encompasses the diverse strategies employed in preventing and mitigating losses associated with social and environmental calamities. Building on the growing literature on risk, we use archaeological data from the Tarapacá Valley, located in northern Chile, to document the risk-reduction tactics mobilized by the valley’s inhabitants to navigate the increasingly volatile environmental and social conditions of the Late Intermediate Period (AD 1000–1450). With the onset of exceptionally unpredictable environmental conditions after AD 1100, residents of the Tarapacá Valley chose strategies such as increased trade and agricultural diversification and extensification to minimize shortages in staple resources. Threats of raiding and intra-community strife exacerbated the risks associated with subsistence shortfalls. Valley communities elected a number of strategies to curtail conflict-induced risk, including movement of settlements and field systems to defensible locations, construction of walls and other defensive features, and the introduction of plazas. Rock art data suggest that trade was increasingly embedded in ritually sanctioned events involving groups from different ecological zones. While studies of risk have focused disproportionately on environmental hazards, subsistence-related crises are often compounded by social hazards that require their own risk-mitigating strategies, further constraining options for coping with subsistence stress.