Droughts during the last 2000 years in a tropical sub-humid environment in central Mexico

High-quality records of hydroclimate variability in central Mexico during the last 2000 years are necessary to better understand human-environment interactions in Mesoamerica. Of particular interest are the climatic conditions during the Epiclassic period (ad 600-900), as droughts have been associated with a cultural demise occurring aroundad 900-1000. We reconstruct the hydroclimate history of the last 2000 years based on a sediment record from a drought-sensitive lake located near one of the most important Epiclassic city-states in Mesoamerica. Titanium concentrations, pollen and diatoms give a consistent environmental signal of five droughts occurring at about: (i)ad 50-250, (ii)ad 700-950, (iii)ad 1200-1300, (iv)ad 1450-1550 and (v)ad 1760-1820. Some droughts were associated with cooler climatic conditions, and all of them framed major historical events. Our results show that the great cultural development of the Epiclassic period (ad 600-900) was framed by a scenario of drought conditions followed by abandonment atad 900-1000. A brief return to moister conditions is recorded before another drought during the time of the fall of the city-state of Tula (1200). European contact (1521) and the War of Independence (1810-20) also occurred during times of drought.