North American Tree Rings, Climatic Extremes, and Social Disasters - Dendroclimatology - page 296

Chapter 10
North American Tree Rings, Climatic Extremes,
and Social Disasters

David W. Stahle and Jeffrey S. Dean

Abstract Tree-ring reconstructed climatic extremes contemporaneous with severe
socioeconomic impacts can be identified in the modern, colonial, and precolonial
eras. These events include the 1950s, Dust Bowl, mid- and late-nineteenth cen-
tury Great Plains droughts, El Año del Hambre, and the seventeenth and sixteenth
century droughts among the English and Spanish colonies. The new tree-ring recon-
structions confirm the severe, sustained Great Drought over the Colorado Plateau
in the late thirteenth century identified by A.E. Douglass and document its spatial
impact across the cultural heartland of the Anasazi. The available tree-ring data
also indicate a succession of severe droughts over the western United States dur-
ing the Terminal Classic Period in Mesoamerica, but these droughts are located far
from the centers of Mesoamerican culture and their extension into central Mexico
needs to be confirmed with the new suite of millennium-long tree-ring chronologies
now under development in the region. The only clear connections between climate
extremes and human impacts are found during the period of written history, includ-
ing the prehispanic Aztec era where codices describe the drought of One Rabbit
in Mexico and other precolonial droughts. The link between reconstructed climate
and societies in the prehistoric era may never be made irrefutably, but testing these
hypotheses with improved climate reconstructions, better archaeological data, and
modeling experiments to explore the range of potential social response have to be
central goals of archaeology and high-resolution paleoclimatology.

Keywords Climate · Dendrochronology · Drought · Epidemic disease · Human

impacts · Megadrought · Palmer Drought Severity Index · PDSI · North America

famines