Environmental Characteristics of the a.d. 900–1300 Period in the Central Mesa Verde Region

This paper has a threefold purpose. First, it reviews environmental evidence proposed to account for the final migrations from the Northern San Juan region: the Great Drought (A.D. 1276–;1299), the advent of the Little Ice Age (ca. A.D. 1200), and a prolonged period of climatic irregularity that began in the thirteenth century (ca. A.D. 1250–;1450). Second, it characterizes environmental variability for the A.D. 900–;1300 interval. Finally, it suggests how altered environmental conditions, interacting with demographic and social factors in the middle of the thirteenth century, may be linked to the migration from the region by Puebloan populations.