Islands No More: Changing Perceptions of the Climate of the Valley of Mexico in the Nineteenth Century

Located in a tropical region but at an altitude that renders it temperate, Mexico City’s two-season weather cycle has long proved a puzzle for inhabitants and visitors.  In 1803, Alexander von Humboldt remarked that the city had ‘a most suitable climate,’ yet the subsequent century hosted scores of events that suggest the climate was far from stable.  Droughts, floods, and dust storms vexed conventional urban life. Repeated wars and rapacious logging leveled the forest reserves that formed the city’s fragile watershed.  Railroads carved up ridges and devoured trees while the associated erosion increased unpredictability in the lives of residents.  In response, federal engineers undertook dramatic measures to stabilize weather-induced vulnerabilities.  Indeed, the era’s largest public works project was the Gran Desagüe,(1886-1901) which sought to finalize the work of desiccating the lakes that had shaped the city’s environs for centuries.  Permanently corralling these waters and turning an island landscape into a built environment was a part of the political project to consolidate power and a manifestation of a new reliance on science and engineering.  Yet, we know much less about how this and other landscape changes influenced the city’s climate or responded to it. Scholars have examined the relationships between climate—particularly drought—and rebellion during the colonial period yet they stop prior to this period of crucial social, cultural, and political change.   The sculpting of the urban environment that occurred in tandem with changing understandings of science and meteorology helps us to understand not only how the climate changed, but what people perceived to be happening. Drawing on popular sources, such as calendars and almanacs, and emerging scientific discourses in journals, this paper suggests some preliminary ideas about the ways in which inhabitants changed their understanding of the city’s climate over the course of the nineteenth century.