That explanation has long dominated scientific thinking. But new findings based on sediment records stretching back 3,300 years suggest the story may be more complicated than a simple climate crisis.

Benjamin Gwinneth, a geography professor at Université de Montréal who studies environmental change and its impact on the Maya, has been investigating the Itzan archaeological site in present-day Guatemala.

By analyzing sediment cores from Laguna Itzan, a nearby lake, Gwinneth and his team have been piecing together a long-term record of both environmental conditions and human activity in the region.

Surprisingly, their results show no signs of drought at Itzan during the period when the Maya population declined. Even so, the local population collapsed at roughly the same time as communities in other parts of Guatemala and Mexico that did experience drought.

So what caused the decline?

Clues From Sediments Reveal Human and Environmental History

To answer that question, the researchers examined three types of geochemical markers preserved in lakebed sediments. These included polycyclic aromatic hydrocarbons, which indicate the intensity of slash-and-burn fires; leaf waxes, which reflect vegetation and rainfall patterns; and fecal stanols, which help estimate population size.

Together, these indicators allowed the team to track changes in population, farming practices, and climate over thousands of years, from the earliest signs of human presence around Laguna Itzan about 4,000 years ago until the site was abandoned roughly 1,000 years ago.

"The data revealed that the first permanent settlements appeared 3,200 years ago," said Gwinneth. "There were slash-and-burn fires and an increase in population. During the Preclassic period, between 3,500 and 2,000 years ago, the Maya used fire extensively. They practiced slash-and-burn agriculture, using fire to clear the forest and then growing crops on the fertile ashes."

Shifts in Maya Agriculture and Urban Growth

During the Classic period, between 1,600 and 1,000 years ago, the data show a major shift. Population density increased significantly, yet the use of fire dropped sharply.

"This probably means that most of the land had been cleared, which could have led to a change in agricultural strategy," said Gwinneth.

The evidence points to more intensive farming methods, such as ridge and furrow ploughing to limit erosion and more focused gardening practices. "Fire was no longer an important component of their farming practices," Gwinneth said. "This transformation reflects gradual urbanization and suggests that the Maya were changing agricultural strategies to feed a growing population."

These findings match what researchers already understand about the Maya at their height. Their society was highly organized, urbanized, and supported by advanced agricultural techniques tailored to local conditions.

Stable Climate at Itzan Challenges Drought Theory

Another key piece of evidence comes from hydrogen isotope analysis, which helps reconstruct past rainfall patterns. Unlike sites farther north that experienced drought, Itzan appears to have maintained a stable climate.

"Itzan is located near the Cordillera, where atmospheric currents from the Caribbean generate regular orographic (mountain-related) rainfall," Gwinneth explained. "While other Maya regions suffered devastating droughts, Itzan appeared to have a stable climate."

This finding is especially important because some scholars have proposed that the Maya collapse began in the southwestern lowlands, where Itzan is located. If drought did not affect this area, it likely was not the initial trigger.

"Even though there were no drought conditions locally, the population of Itzan declined sharply during the Terminal Classic period, between 1,140 and 1,000 years ago," Gwinneth continued. "Population markers show a dramatic fall, signs of agriculture disappear, the site was abandoned."

This raises a key question: why did a community with reliable water and favorable conditions decline at the same time as drought-affected regions?

Interconnected Maya Cities and a Cascading Collapse

"The answer lies in the interconnectedness of Maya societies," said Gwinneth. "The cities did not exist in isolation; they formed a complex network of trading relationships, political alliances and economic dependence.

"When the central lowlands were hit by drought, this may have triggered a cascading series of crises: wars between cities over resources, the collapse of royal dynasties, mass migrations, disruption of trade routes, and so on."

Under this scenario, Itzan did not fall because of local environmental stress. Instead, it was pulled into a broader regional breakdown as the larger system unraveled.

Because Maya cities were so closely linked, problems in one area could quickly spread. Drought in key regions may have sparked instability that rippled outward, creating a chain reaction across the entire civilization.

"The transformation or "collapse" of the Maya civilization was not a mechanical result of a uniform climate catastrophe; it was a complex phenomenon in which climate, social organization, economic networks and political dynamics were intertwined," Gwinneth concluded.

"Regional socio-political and economic factors played a decisive role."

Gwinneth believes these insights matter beyond ancient history, offering a window into how interconnected societies today might respond to environmental challenges.