“Unusually high amounts of rainfall favoured an increase in food production and an explosion in the population between AD 450 und 660,” says Douglas Kennett, lead author and professor of anthropology at Pennsylvania State University. “This led to the proliferation of cities like Tikal, Copan and Caracol across the Maya lowlands. The new climate data show that this salubrious period was followed by a general drying trend lasting four centuries that was punctuated by a series of major droughts that triggered a decline in agricultural productivity and contributed to societal fragmentation and political collapse.”
A stalagmite from a cave close to the ancient city of Uxbenka in the tropical Maya Lowlands in southern Belize was analysed from researchers from the Penn State in the USA, the Eidgenössische Technische Hochschule Zürich in Switzerland, the University of Durham in the UK and inter alia the PIK. Stalagmites grow with humidity. Using the radioactive decomposition of uranium to thorium, the scientists examined the age structure of the stalagmite and were able to reconstruct detailed rainfall records for this region. They compared these records to the rich political histories carved on stone monuments at Maya cities throughout the region, hypothesizing that precipitation-induced changes in agricultural productivity mediated the tendency toward political integration or disintegration in the Maya Lowlands.
The long-term drying trend in the region was followed by the population collapse in the context of an extended drought between 1020 and 1100, according to the scientists. Norbert Marwan from PIK contributed to the study by a comprehensive computer analysis of the stalagmite’s age data, factoring in uncertainties about possible age data ranges. This resulted in the actual climate record. “Although climate change may be only one factor among others to cause changes in whole civilizations like the Maya, our study shows that climate change is capable of having major implications on society at large,” says Marwan.
Article: Douglas J. Kennett, Sebastian F. M. Breitenbach et.al: Development and Disintegration of Maya Political Systems in Response to Climate Change. Published in Science Vol. 338 no.6108 pp. 788-791. DOI:10.1126/science.1226299
Weblink to the article: http://www.sciencemag.org/content/338/6108/788
