This study explores the dynamic interplay between biogeography, climate variability, and human agency in shaping the population trajectories of Amazigh communities in the Canary Islands (1st to fifteenth centuries cal CE). Using radiocarbon dating as a proxy for population size, this research suggests potential links between demographic trends and environmental factors, highlighting how climatic phases influence agricultural productivity and settlement patterns. Favorable conditions during the Roman Warm Period (RWP) facilitated population expansion, whereas climatic stress during positive phases of the North Atlantic oscillation (NAO) (700–800 cal CE) led to significant demographic declines, particularly on smaller and more arid islands. Larger and ecologically more diverse islands, such as Gran Canaria and Tenerife, showed resilience due to their ecological diversity, agricultural innovations, and food security strategies, which supported sustained growth even during challenging periods such as the Early Medieval Climate Anomaly (MCA, 800–1150 cal CE). From 1150 to 1350 cal CE, cooler sea surface temperatures and a prevailing negative NAO phase increased marine productivity, enabling demographic recovery across islands. However, the arrival of Europeans in the fourteenth–fifteenth centuries introduced external disruptions, including slave raids, novel pathogens, and land seizures, leading to societal collapse. Overall, this study highlights the critical role of environmental diversity and agricultural adaptability in supporting human populations through climatic change and offers valuable perspectives on the relationships among climate, biogeography and human societies.
