The Maya civilization, which occupied much of modern-day Mexico and Central America, collapsed rapidly between 800 and 1000 AD. This collapse has often puzzled archaeologists. There hasn’t been a clear explanation for why the society collapsed, which was known for its sophisticated calendar system and pyramid construction.
The scientists published their findings in the journal Science and they indicate that the collapse was due to extreme climate changes. The scientists analyzed 2,000-year-old stalagmites from a cave in southern Belize and studied archaeological records. Palaeoclimatologist Douglas Kennett of Pennsylvania State University in University Park and his colleagues think that unusual rainfall patterns accelerated the fall of the Maya people.
The team estimated rainfall in the Mayan lowlands by measuring oxygen isotopes incorporated into the stalagmite from rainwater, which had seeped into the cave from above. These precipitation levels were tied to specific dates by measuring the rate of radioactive isotopes in the stalagmite.
Unusually high rainfall promoted a population boom between 440 and 660 AD. There were also protracted dry conditions between 660 and 1000 AD, which aligns with a period of political instability among the Maya.
Kennett’s error margins are between 1 and 17 years. Previously, they were about 100 years in carbon-dating efforts. Drought was a key factor, but some researchers believe that the relative rainfall inferred from the stalagmite should be calibrated against actual recorded precipitation, which is available for the modern segment of the stalagmite.
Some palaeoclimatologists are skeptical of the team’s association of climate change with cultural records, but the study could have important implications for climate modeling because it seems to indicate that extreme droughts may have occurred 1,000 years ago.
Reference: “Development and Disintegration of Maya Political Systems in Response to Climate Change” by Douglas J. Kennett, Sebastian F. M. Breitenbach, Valorie V. Aquino, Yemane Asmerom, Jaime Awe, James U.L. Baldini, Patrick Bartlein, Brendan J. Culleton, Claire Ebert, Christopher Jazwa, Martha J. Macri, Norbert Marwan, Victor Polyak, Keith M. Prufer, Harriet E. Ridley, Harald Sodemann, Bruce Winterhalder and Gerald H. Haug, 9 November 2012, Science.