Corn, Climate, and the Human Population of Greater Cahokia

At its peak, the urban complex of Greater Cahokia likely had a population of between 15,000 and 20,000 people, with a social, political, and religious influence that covered the midcontinent. New excavations at Cahokia’s East St. Louis Precinct, paired with existing isotopic studies and climatic data afford us previously unavailable insights into factors which contributed to the rise and dissolution of the city between ca. AD 1000 and 1300. We argue that migration into Greater Cahokia played a causal role in the rapid intensification of maize agriculture and associated processing technology. Isotopic evidence indicates immigrants from a variety of backgrounds likely contributed significantly to both the creation and demise of the new city. In this chapter, we review the evidence in light of regional climatic changes and conclude that while climatic shifts facilitated both the formation and dissolution of Cahokia it was the human social, political and religious variables that hold the key to these processes.