Climate Change, Subsistence and Warfare during the Late Pre-Columbian Period in the Lower Midwest

Summary

Archaeologists are increasingly turning to climate change as part of their explanatory models of regional and interregional population movement, socio-cultural transformation, and the dissolution of societies in North America. In the lower Midwest, both megadroughts and megafloods have been invoked to explain declining agricultural returns, rises in conflict, and abandonment of major river valleys during the latter half of the Mississippian Period. However, the data sources and indices recording rainfall and drought have often been extrapolated over broad geographic expanses, introducing unnecessary ambiguity.

Here, we deliver the first high-resolution record of hydroclimate change over the last 2,500 years in the Midwest. These data are examined in conjunction with the isotopic record for subsistence change and the spatiotemporal patterning of fortified settlements. Sediment cores from lakes in Indiana provided isotopic and lithologic data that demonstrate considerable fluctuations in atmospheric moisture during the Medieval Climate Anomaly (MCA) and subsequent Little Ice Age (LIA). A prolonged wet period during and prior to the MCA is followed by a LIA-era drought that lasted for approximately 500 years. This research convincingly demonstrates a close relationship between prolonged severe drought and population dynamics during the depopulation of the lower Midwest between AD 1300 and 1450.

This Resource is Part of the Following Collections

• Society for American Archaeology 81st Annual Meeting, Orlando, FL (2016)

Keywords

Spatial Coverage