The role of climatic anomalies in agricultural instability and settlement abandonment in northeastern Germany during the migration period

Abstract The Late Antique Migration period (LAMP; 300–700 CE) in what is today northeastern Germany was marked by significant socio-environmental shifts, including a decline in human activity, the abandonment of settlements, and a reduction in cereal cultivation, particularly of rye ( Secale cereale ). While these changes are well documented in pollen and archaeological records, the underlying drivers—whether socio-political instability, agricultural crises, or environmental pressures—remain debated. Here, we use a multiproxy approach comprising high-resolution pollen data, archaeobotanical data, and climate reconstructions specific to the study area to explore the interplay between climatic fluctuations, agricultural practices, and human mobility during the LAMP. Although previous studies have examined socio-environmental changes during the Migration period using archaeological and palynological evidence, this study is the first to integrate these three proxies to systematically evaluate the role of climatic anomalies in shaping agricultural and demographic patterns. We focus on the Dark Age Cold Period (DACP; 350–700 CE) and the Late Antique Little Ice Age (LALIA; 536–660 CE), which brought cold and wet conditions to northern Europe, likely disrupting agricultural productivity and fostering the spread of Claviceps purpurea (ergot), a fungus toxic to humans affecting cereal crops, particularly rye. Our findings suggest that these two climatic anomalies created favorable conditions for outbreaks of ergot, leading to agricultural instability and reduced food security, which, combined with socio-political pressures, contributed to the observed decline in human activity and settlement abandonment. We suggest that climatic anomalies in the DACP and the LALIA, coupled with the vulnerability of cereal crops to ergot infestation, influenced agricultural and demographic shifts in northeastern Germany. This paper not only refines our understanding of the DACP and the LALIA, but also demonstrates how climatic stressors and natural hazards can amplify socio-political vulnerabilities in pre-industrial societies.