National Geographic News has an interesting discussion of how climate change resulted in the Mayan decline and inland demise.
The latest Maya climate-change study, published Friday in the journal Science, analyzes a Belizean cavern’s stalagmites—those lumpy, rocky spires on cave floors—to link climate swings to both the rise and fall of the empire.
Formed by water and minerals dripping from above, stalagmites grow quicker in rainier years, giving scientists a reliable record of historical precipitation trends. One sample used in the new study, for example, documents fluctuations as far back as 2,000 years ago.
Among the trends revealed by the Belizean stalagmites: “The early Classic Maya period was unusually wet, wetter than the previous thousand years,” according to study leader Douglas Kennett, an environmental anthropologist at Pennsylvania State University. “During this time, the population proliferated,” aided by a surge in agriculture.
During the wettest decades, from 440 to 660, cities sprouted. All the hallmarks of Maya civilization— sophisticated political systems, monumental architecture, complex religion—came into full flower during this era.
(Read about the rise and fall of the Maya in National Geographic magazine.)
Climate Shift Sparks Conflict
But the 200-year-long wet spell turned out to be an anomaly. When the climate pendulum swung back, hard times followed.
“Mayan systems were founded on those [high] rainfall patterns,” Kennett said. “They could not support themselves when patterns changed.”
The following centuries, from about 660 to 1000, were characterized by repeated and, at times extreme, drought. Agriculture declined and—not coincidentally—social conflict rose, Kennet says.
The Maya religious and political system was based on the belief that rulers were in direct communication with the gods. When these divine connections failed to produce rainfall and good harvests, tensions likely developed.
Within the scant 25 years between 750 and 775, for example, 39 embattled rulers commissioned the same number of stone monuments—evidence of “rivalry, war, and strategic alliances,” according to Kennett’s study.
But times would get even harder.
The stalagmite record suggests that between 1020 and 1100 the region suffered its longest dry spell of the last 2,000 years. With it, the study suggests, came Maya crop failure, famine, mass migration, and death.
By the time Spanish conquistadors arrived in the 16th century, inland Maya populations had decreased by 90 percent, and urban centers had been largely abandoned. Farms had become overgrown and cities reclaimed by forest.
You can read the rest of the article HERE.
This is more evidence that climate change is cyclical, with warm and cold periods, wet and dry periods. The Sierra has experienced long periods of drought lasting 200 to 2000 years long. We are currently living in a moderate period much like the Maya from 440 to 660. The notion that humans can control the climate is just pain foolish, a political wet dream that can be used to scare us in to paying carbon taxes.