Rivers of God, Rivers of Empire: Climate Extremes, Environmental Transformation and Agroecology in Colonial Mexico

This paper explores the social-ecological effects of the Little Ice Age (1300-1850) in colonial Central Mexico. Archival research reconstructs the history of climate, soil, water and agriculture in two Central Mexican watersheds: the Zahuapan River in Tlaxcala and the San Juan River in the Teotihuacan Valley. I clarify social-ecological and landscape responses to climate stress, along with changing human resilience/vulnerability to anomalous weather. The methodology is interdisciplinary, comparing natural climate archives (plant and mineral) to historical climate archives (texts and images), examining hydrological and edaphic evidence and contextualising social-ecological change within a framework of indigenous agrarian innovation. Together, this research reveals a critical transition from nature-induced to anthropogenic cataclysms after the Late Maunder Minimum (1684-1713). Before this disjuncture, floods were rare events driven by extraordinary precipitation and without significant hydromorphological change. Afterward, cataclysms were frequent, poorly correlated to precipitation trends and determined by anthropogenic accelerated soil erosion that transformed watersheds. Evidence from both basins demonstrates the rapid onset of deep hillside erosion and valley sedimentation after 1715. I argue that the combined ecological shock of colonialism and climate was mediated by early-colonial indigenous agrosystems, resulting in transformation without lasting degradation. The transformative potential of the Little Ice Age lay dormant until the Late Maunder Minimum intersected with the metepantli system, a new agrarian regime based on the cultivation of agave plants in monocropped sloping terraces for the extraction of pulque (a beer-like beverage), whose economic wealth belied its impoverished ecology. Not only does this paper challenge - even negate - arguments that link degradation to early-colonial biology, pre-Columbian agriculture or eighteenth-century population growth; it identifies the Late Maunder Minimum as a transformative moment in colonial ecosystems - and, by extension, society - that gave rise to a degraded and devious landscape.