The Maya was one of the most advanced civilizations in history, and its seemingly sudden disappearance has remained unexplained until recently. A paper published in the November 9 issue of Science, written by a research team led by environmental anthropologist Douglas Kennett, presents its case for how climate change led to the downfall of the Maya civilization.
The team began its research six years ago in Yok Balum, a cave in the Belizean jungle. The cave has many speleothems, which are mineral deposits that form over the course of thousands of years. Stalagmites are a type of speleothem that rise upward from the cave floor. Some stalagmites contain a detailed history of the surrounding region's rainfall. Kennett's team found a 56-centimeter-long stalagmite, 50 meters from the cave's entrance, that contained an abundance of climatic data. They named the formation YOK-1.
Radiometric dating showed that YOK-1 had grown 41 centimeters continuously from 40 B.C.E. until its discovery in 2006. After performing analysis at the rate of a tenth of a millimeter at a time, the researchers were able to create a record of rainfall during this period at six-month increments.
The rainfall record was compared alongside historical records such as the span of Mayan centers across time and the recorded wars between various Maya settlements. The team found that periods of wetness generally indicate a healthy Maya society while dryer periods led to unrest. "Rainfall feeding the Maya's wetland farming systems worked really well, until they were faced with a climatic downturn. That's where you see a trend toward drying, and it's during that interval when you start getting these peaks in warfare, but you also get proliferation of competing centers," Kennett says.
Kennett maintains that if there is anything to take from his team's research, it is that these records are relevant to our current global climate change. He says that there is too much emphasis placed on abrupt weather events, when we should really be focusing on the changes our climate has made on a long-term scale. "The connections between climate and war and societal instability are ones that we think are important. Ones that we should be concerned about in light of our current situation."
If there is anything to take from this recent discovery it may be that it is in our best interest to find a way to positively affect our climate on a long-term scale. If we are successful, then we will have changed the world for the better. If we fail, our demise may be similar to the Maya.
Image by Rubén Chase, courtesy of Creative Commons licensing.