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

ABSTRACT

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.

KEYWORDS

Climate disasters, ecological resilience, land degradation, water history

INTRODUCTION

Just months after the beginning of a five-year flood from 1629 to 1634 that nearly ruined Mexico City, Carmelite friar Andres de San Miguel identified the cause of the current cataclysm to be changes 'in the weather in the last few years', particularly 'in the way that it rains':

It used to be temperate, raining mostly by day, beginning at one or two until four or five in the afternoon, such that one day's rainfall would be cleared up by the next day, causing little rise in the lake [of Mexico]. Nowadays it rains at all hours, and more commonly at night than day... While in years past, the torrential downfalls did not remain on the ground long after the sun came out to clear up the land and make it ready for more rain, the rains these last years... are continuous, drench the land and greatly enrich and augment the springs... such that one day of these rains has greater effect than a month of crazy downpours. (1)

As San Miguel recorded his thoughts. Central Mexico was experiencing the worst multi-decadal climate anomaly of the last millennium (1594-1645), which brought cold, floods, drought, famine, epidemics, epizootics and socio-economic turmoil. It was the second such chmate...