How Traditional Ecological Knowledge and Climate Science can Inform Archaeological Inferences. Predicting Good & Bad Harvest Years among Maya Subsistence Agriculturalists
Authors
Karen L. Kramer1 and Russell D.Greaves2
1 Professor of Anthropology, University of Utah, Salt Lake City, UT (karen.kramer@anthro.utah.edu).
2 Maxwell Museum, Director Office of Contract Archaeology, University of New Mexico, Albuquerque, NM, (rgreaves@unm.edu).
Abstract
Human response to climate change has a rich ethnographic and archaeological history. An extensive archaeological literature links climate stress to the fall of the ancestral Maya, with drought being the prevailing explanation for their demise. While inferences often are drawn from climate data to explain past events, relatively little is known about how small-scale agriculturalists actually experience climate variation, and what climate data are useful in predicting food production. Our ethnographic perspective from longitudinal research integrates traditional ecological knowledge and climate science as tools to inform archaeological inferences. To do so we address three related questions: What do Maya farmers tell us is important about the climate for food production? At what scale do climate data reflect how good and bad harvest years map onto the local precipitation record? How does paleoclimatic data affect the usefulness of archaeological inferences, and specifically in determining the cause of the Maya demise?
To address these questions, we use 30-years of ethnographic interview and economic data collected among Yucatec Maya subsistence farmers to assess those aspects of climate variation that affect agricultural cycles and food production. Sixty years of high-resolution meteorological data and crop yield assessments are used to detect how climate data predict good and bad crop yields. We find that 1) Maya farmers accurately gauge climate risk and identify two climate vulnerabilities during the growing season, with the greatest negative impact on crop yields being heavy late-season rains associated with severe tropical storms, not drought. 2) Only the daily precipitation record closely fits the climate pattern described by farmers. Based on these ethnographic data, other temporal scales (average annual and monthly precipitation) miss key information that farmers find important to produce successful harvests. This suggests that fine-grained data are needed to make accurate inferences about the past human behavior, which is an important result because the finest-grained climate data often available to archaeologists and paleoclimate are annual proxies. While annual measures are useful to address long-term shifts in climate, they may not reflect the scale at which the climate affects food production. These findings highlight the need for exchange among archaeology, ethnography and climate science to define climate variables at scales appropriate to human behavior.
People living in small-scale societies close to the means of production are astute stewards of climate knowledge and provide valuable insights into the scale at which climate affects human livelihoods. From this perspective, we emphasize that rather than finding compelling patterns and signature changes in the annual climate data and then making inferences about the archaeological past, there is great value in working the other way around –evaluating what is important about the climate to people's lives, and then ask how those aspects of the climate might be changing.