From 750 to 900 AD, the Maya lowlands in Central America experienced a significant demographic and political decline, a period that coincides with a string of severe droughts. For decades, scholars assumed that the collapse of Maya civilization was primarily due to this climatic crisis. However, an analysis of 3300 years’ worth of sediment core samples partially challenges this widely accepted explanation.
Professor Benjamin Gwinnett, a geography professor at the University of Montreal who studies environmental shifts and their impact on Maya civilization, conducted extensive research at the site of Itzan in modern-day Guatemala. Together with his colleagues, he reconstructed the history of human activity and climatic conditions in the area by examining sediment cores taken from Laguna Itzan, a lake adjacent to the archaeological site. The findings of this study were published in the journal Biogeosciences.
The researchers found no evidence of droughts in that specific region. Nevertheless, the Maya population there declined concurrently with neighboring regions that demonstrably suffered from drought. So, what is the explanation?
Traces of Humans and Nature in Lake Sediments
Gwinnett’s team focused on three geochemical indicators present in the sediment deposits of Lake Itzan:
- Polycyclic Aromatic Hydrocarbons (PAHs), which indicate the intensity of slash-and-burn agriculture;
- Leaf waxes, which hint at vegetation type and local precipitation levels;
- Coprostanois (a fecal biomarker), used to estimate population density.
These markers allowed for a simultaneous reconstruction of population dynamics, agricultural practices, and climate, spanning from the first signs of human presence around Laguna Itzan 4000 years ago right up to the time the settlement was abandoned around 1000 years ago.
“The data showed that the first permanent settlements emerged 3,200 years ago. We observe evidence of forest clearing and population growth. During the Preclassic period, between 3,500 and 2,000 years ago, the Maya made extensive use of fire. They practiced slash-and-burn agriculture, clearing forest and planting crops in the fertile ash,” explains Gwinnett.
New Farming Methods
Radical changes occurred during the Classic period, between 1,600 and 1,000 years ago: despite the population becoming significantly denser, the use of fire dramatically decreased.
“This likely means that a large portion of the land had already been cleared, which could have led to a change in agricultural strategy,” the professor posits.
The data points to a substantial intensification of agriculture, including the use of raised fields and furrows to mitigate soil erosion, alongside the development of intensive gardening.
“Fire ceased to be a major component of their farming practices,” the scientist notes.
These shifts reflect a process of gradual urbanization—and align with what archaeologists and anthropologists know about the Maya civilization at its peak: it was a complex, urbanized society featuring growing specialization and advanced agricultural techniques adapted to the environment.
The Mystery of Stable Climate
Meanwhile, analysis of hydrogen isotopes indicated that, unlike the northern city-states plagued by drought, Itzan apparently maintained a stable climate due to its geographical position.
“Itzan is situated next to a mountain range where atmospheric currents from the Caribbean Sea generate regular orographic rainfall. While other Maya regions were experiencing devastating droughts, the climate in Itzan remained steady,” the researcher emphasizes.
He considers this a crucial finding because some archaeologists had argued that the Maya collapse began in the southwest. The absence of drought there suggests it could not have been the initial cause of the decline.
“Despite the lack of local arid conditions, the population of Itzan sharply decreased toward the end of the Classic period, between 1,140 and 1,000 years ago,” Gwinnett continues. “Population markers show a steep drop, agricultural signs vanish, and the settlement was abandoned.”
Why then did a community possessing ample water and favorable conditions share the fate of its neighbors who were ruined by drought?
Fatal Interdependence
“The answer lies in the interconnectedness of Maya societies. Cities were not isolated; they formed a complex network of trade, political alliances, and economic dependencies,” the professor explains. “When drought struck the central lowlands, it probably initiated a cascade of crises: inter-city warfare over resources, the collapse of ruling dynasties, mass migrations, disruption of trade routes, and so on.”
According to this theory, Itzan collapsed not due to a local water shortage, but because it was pulled into the chaos as the very system of which it was a part disintegrated. While drought may have been a significant contributing factor, it generated a domino effect that spread far beyond the stricken areas.
“The transformation, or ‘collapse,’ of Maya civilization was not a mechanical result of a single climatic catastrophe—it was a complex phenomenon where climate, social organization, economic networks, and political dynamics were intertwined,” Gwinnett concludes. He is convinced these findings are relevant today, as they can shed light on how civilizations respond to environmental changes.
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