Archaeological perspectives on the effects of medieval drought in prehistoric California

Inspired by Stine's [1994. Extreme and persistent drought in California and Patagonia during Mediaeval Time. Nature 369, 546–549.] findings from Mono Lake and Graumlich's [1993. A 1000-year record of temperature and precipitation in the Sierra Nevada. Quaternary Research 39, 249–255.] tree-ring study from the southern Sierra Nevada, California archaeologists have for over a decade been investigating the possibility that prehistoric societies were noticeably impacted by severe droughts during the Medieval Climatic Anomaly (MCA; cal A.D. 800–1350). Decreased production at obsidian sources, dramatic increases in bead production, trade, and sociopolitical complexity in the Channel Islands, and subsistence changes on the central coast were among the trends attributed to drought-related demographic stress by researchers in the 1990s. Review of more recent archaeological research shows that as the search for signs of unusual cultural changes during the MCA has broadened, some of these early patterns (e.g. violence and health problems) have been found to be more complicated and regionally varied than previously thought while others (e.g., settlement disruption, deterioration of long distance trade, and population movements) have been further corroborated.