Scientists analyzing sediments from a lake near the ancient Maya city of Itzan in Guatemala found no signs of drought during the period of population decline around 800-900 CE. The study suggests the collapse resulted from interconnected regional crises rather than local climate failure. Itzan maintained stable rainfall while neighboring areas suffered droughts.
Between 750 and 900 CE, the Maya lowlands experienced a sharp drop in population and political power. Researchers have traditionally attributed this to severe droughts, but a new analysis of lake sediments from Laguna Itzan challenges that view at the Itzan site in Guatemala's southwestern lowlands. Benjamin Gwinneth, a geography professor at Université de Montréal, led the study published in Biogeosciences in 2025. The team examined geochemical markers including polycyclic aromatic hydrocarbons for fires, leaf waxes for rainfall and vegetation, and fecal stanols for population size, covering 3,300 years of history. The data showed permanent settlements emerging 3,200 years ago with extensive slash-and-burn agriculture in the Preclassic period. By the Classic period, from about 1,600 to 1,000 years ago, fire use declined sharply amid rising population and urbanization, indicating a shift to intensive farming like ridge ploughing to sustain growth. Hydrogen isotope analysis confirmed stable climate at Itzan, thanks to orographic rainfall from Caribbean currents near the Cordillera mountains. Yet, population markers indicate a dramatic decline during the Terminal Classic, from 1,140 to 1,000 years ago, coinciding with collapses elsewhere. Gwinneth attributes this to the Maya cities' tight interconnections through trade, politics, and economics. Droughts in central lowlands likely sparked wars, migrations, and trade disruptions that rippled outward, pulling stable sites like Itzan into the downfall. 'The transformation or collapse of the Maya civilization was not a mechanical result of a uniform climate catastrophe; it was a complex phenomenon,' Gwinneth said.
