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Debilitating Drought and the Classic Mayan Collapse
Reference
Webster, J.W., Brook, G.A., Railsback, L.B., Cheng, H., Edwards, R.L., Alexander, C. and Reeder, P.P. 2007. Stalagmite evidence from Belize indicating significant droughts at the time of Preclassic Abandonment, the Maya Hiatus, and the Classic Maya collapse. Palaeogeography, Palaeoclimatology, Palaeoecology 250: 1-17.

What was done
An active stalagmite (MC01) was removed from the entrance chamber of Macal Chasm -- a cave on the Vaca Plateau west of the Rio Macal in the Cavo District of Belize near the border with Guatemala (~17N, 89W) -- from which the authors obtained "reliably dated reflectance, color, luminescence, and C and O stable isotope records for the period from 1225 BC to the present."

What was learned
As Webster et al. describe it, "the interval in our record from AD 750 to 1150 was the most prolonged dry phase in our 3300-year record," which period of time can be seen from the Interactive Map and Time Domain Plot of our Medieval Warm Period (MWP) Project to correspond well with the MWP's mean time of occurrence around the globe, which period, in their words, "coincided with the collapse of the Maya civilization." More specifically, they say their data depict "a series of droughts centered at about AD 780, 910, 1074, and 1139," with "successive droughts increasing in severity."

What it means
In concluding their paper, the seven scientists state that the results of their investigations "add to a growing body of evidence suggesting that severe dryness affected a broad region of Mesoamerica and contributed to the collapse of the Maya civilization during the Late Classic period." Consequently, although the warmth of the MWP was beneficial to Norse settlers on Greenland, its dryness across a broad swath of Mesoamerica spelled an end to the indigenous civilization of that region.

Reviewed 17 September 2008