Overview

• A 871–1021 CE stalagmite from Grutas Tzabnah in Yucatán provides the first seasonal-resolution oxygen-isotope record for the Classic Maya period.
• The record documents eight severe wet-season droughts, including a 13-year stretch from about 929 to 942 CE and a total of 44 years of extreme drought conditions.
• Drought phases align with drops in monument building and political activity at key northern centers such as Chichén Itzá and Uxmal.
• Uxmal’s political system collapsed soon after the longest drought while Chichén Itzá’s extensive trade networks and water-management infrastructure helped it endure longer.
• The research team will now match the stalagmite’s year-by-year drought timeline with site-specific archaeological data to refine insights into local societal impacts.