A team of researchers led by Lars Fehren-Schmitz at UC Santa Cruz has examined DNA evidence from populations that lived in Peru between 840 BC and 1450 AD. Their investigations have revealed evidence of two major human migrations in the Central Andes in response to periods of drought and significant climate variability.
Most studies analyzing the impact of climate on the mobility and demography of ancient populations have concentrated on foraging societies. Here we reveal climatic impacts on socially complex, agricultural societies. Despite a range of anticipatory agricultural adaptations observed in the archaeological record, the instability of the coastal and highland ecosystems in southern Peru exceeded critical points in the past in which migration became inevitable to sustain the population.
(Lars Fehren-Schmitz et al., "Climate change underlies global demographic, genetic, and cultural transitions in pre-Columbian southern Peru," Proceedings of the National Academy of Sciences, May 22, 2014)