A 2400 yr Mesoamerican rainfall reconstruction links climate and cultural change

Abstract

Droughts are a recurring feature of Mexican climate, but few high-resolution data are available to test for climate-change forcing of Mesoamerican civilizations. We present a quantitative 2400 yr rainfall reconstruction for the Basin of Mexico, from a precisely dated and highly resolved speleothem, that documents highly variable rainfall over the past 2400 yr. Dry conditions peaked during a 150-yr-long late Classic (ca. 600-900 CE) (Common Era) mega drought that culminated at 770 CE which followed centuries of climatic drying that spanned the fall of the city of Teotihuacán ca. 550 CE. The wettest conditions in the 1450s CE were associated with fl ooding in the Basin of Mexico. Our data suggest that rainfall variability was likely forced by the El Niño-Southern Oscillation, and impacts on spring-fed irrigation agriculture may have been a stressor on Mesoamerican civilizations.

Persistent drying in the tropics linked to natural forcing

“…The drying steps are separated from one another by brief intervals of precipitation recovery in mid-century. Our and other available d 18 O records from Mesoamerica 17,18 correlate with each other with variable strength during the reconstruction period (Fig. 6, Supplementary Figs 1, 2), in part reflecting large dating uncertainties in some of the reconstructions.…”

“…5d, brown). (a) GU-Xi-1 (this study); (b) southwestern Guerrero (Mexico) 17 ; and (c) Yucatán peninsula (Mexico) 18 . Open circles represent the raw data from each record.…”

Cultural implications of late Holocene climate change in the Cuenca Oriental, Mexico

“…It is also possible that Cantona's strategic location may have attracted migrants, fleeing environmental stress or political upheavals elsewhere in central Mexico, although further research is necessary to explore this hypothesis. Some researchers have linked these late Classic political upheavals with climatic drying (1,2). It is important to note, however, that while sites like Cholula underwent significant periods of decline between 650 CE and 850 CE, other factors apart from climate, like invasion or volcanic eruptions, may have played a significant role in these cultural transitions.…”

“…A focal point of this debate is the dramatic cultural change that occurred during the Terminal Classic, from ∼850 CE through 1000 CE. Much of this debate has focused on the Maya lowlands (3,7), although researchers have also explored linkages between climate and cultural change in Terminal Classic highland Mexico (1,2,4). However, these comparisons have been hindered by a lack of high-resolution paleoclimate records: While paleoclimate records from across Mesoamerica suggest arid conditions at some point during this interval (1)(2)(3)(6)(7)(8), patterns of climatic change may have been regionally heterogeneous.…”

“…While some scholars argue for a direct causal link between aridity and the abandonment of many sites (1)(2)(3)(4), others argue that anthropogenic landscape transformations were more important in facilitating cultural change (5,6). A focal point of this debate is the dramatic cultural change that occurred during the Terminal Classic, from ∼850 CE through 1000 CE.…”