Over the past several decades, scientists have proposed multiple theories to explain the collapse of the Mayan civilization. Historians have linked their demise with everything from overhunting to deforestation to a peasant uprising to an alien invasion. Only one concept has gained some credibility in recent years: severe drought. Since 1995, scientists have been looking closely at the effects of drought. Now a new research suggests that a century-long drought was indeed responsible for the collapse of the ancient Mayan civilization, reports LiveScience.

Severe Drought Ushered In The Collapse Of Mayan Civilization

Mayan civilization flourished between AD 300 and AD 700

A previous study published in the journal Science in 2012 analyzed a 2,000-year-old stalagmite from a cave in Belize. Researchers found that the decline in rainfall coincided with the period of collapse of Mayan civilization. The Mayan civilization bloomed between AD 300 and AD 700 in the Yucatan peninsula.

They mastered astronomy, built pyramids, developed a calendar system and a hieroglyphic writing system. But their building activities slowed significantly after AD 700. Scientists led by Andre Droxler of Rice University found the proof in the Blue Hole, the most famous underwater cave in Belize, as well as some lagoons nearby.

Droxler and his colleagues drilled cores from the sediments in the Blue Hole. They analyzed its chemical composition, with a special focus on the ratio of titanium to aluminum. During periods of ample rainfalls, titanium in the volcanic rocks of the region is swept into streams that reach the ocean. So, says Droxler, a lower ratio of titanium to aluminum indicates periods with less rainfall.

Mayans later moved to Chichen Itza but…

They found that an extreme drought occurred between AD 800 and AD 900, which coincides with the collapse of the Mayan civilization. Researchers blame a shift in the intertropical convergence zone (ITCZ) for this drought. During summers, this monsoon system dumps water on the Yucatan peninsula. Many scientists in the past have suggested that the ITCZ might have missed the Yucatan peninsula altogether during the Mayan decline.

After that, Mayans moved north to sites like Chichen Itza (now in Mexico). But they disappeared again a couple of centuries later. Droxler and his colleagues found that a second severe drought occurred between AD 1000 and AD 1100, which coincides with the collapse of Chichen Itza. “When you have major droughts, you start to get famines and unrest,” Droxler said.