Then, sometime around 900 A.D., Mayan society collapsed. No one is sure why. But, after years of speculation, a new study provides further evidence for a oft-named cause: drought.
To measure drought’s affect on the Mayans, Rice University scientist Andre Droxler looked at mineral deposits in the Great Blue Hole — a 1,000-foot crater about 40 miles off the coast of Belize. Taking core samples from the sediment, Droxler’s team looked at the ratio of titanium to aluminum. When it rains a lot, titanium from volcanic rocks ends up in the Atlantic Ocean — and in the Great Blue Hole. During drier periods, there’s less titanium to be found. The Great Blue Hole is “like a big bucket,” Droxler told LiveScience. “It’s a sediment trap.”
Doing the math, Droxler found less titanium from sediment samples dated to the Mayans’ demise. As Live Science put it: “The team found that during the period between A.D. 800 and A.D. 1000, when the Mayan civilization collapsed, there were just one or two tropical cyclones every two decades, as opposed to the usual five or six.”
Cyclones are powerful storms that can wreak havoc. But they also bring the H2O that prevents a pre-industrial society from starving.
Evidence of drought has been mounting. A 2012 study in the journal Science analyzed a 2,000 year old stalagmite from a cave in Belize and also “found that sharp decreases in rainfall coincided with periods of decline in the culture,” said Discovery.