The Mayan civilization probably collapsed due to extreme droughts, according to new research published in the journal Scientific Reports.
Between the years 800 CE (Common Era) and 1000 CE, there appear to be two major droughts that led to the civilization's demise.
Researchers from Rice University and Louisiana State University studied sediment from the Blue Hole of Lighthouse Reef in Belize, near the lands where the Mayans first thrived then collapsed.
"When you have major droughts, you start to get famines and unrest," Rice University Researcher André Droxler told Live Science.
In analyzing the elements found in the sediment, the researchers said unusually low titanium counts and titanium/aluminum ratios show that there was low precipitation resulting in extreme droughts at the same time of the Mayans' collapse.
The Mayans existed from about 2000 BCE (Before Common Era) to 1000 CE. They lived in what is now southern Mexico, the Yucatan Peninsula, Guatemala, Belize, western Honduras and extreme northern El Salvador.
"This region certainly is susceptible to drought," AccuWeather.com Senior Meteorologist Jason Nicholls said. "In fact, El Niños tend to result in below-normal rainfall and above-normal temperatures across these areas."
Droughts coincide with the ENSO (El Niño Southern Oscillation) but are not necessarily cyclical, Nicholls said. Sea surface temperatures can play a big part in causing droughts, and since water temperatures tend to be slower to change, it can cause droughts to carry over for multiple years.
Nicholls cited Columbia University research which showed tree-ring records that indicated a severe drought in Mexico during the late 16th century.
"Given that there was a very severe drought in the late 16th century, it is reasonable to assume there could have been a 'mega drought' during the time of the Mayans," he said.
"Droughts still impact the Mexican economy today, so a 'mega drought'- or 'dust bowl'-type drought back in the time of the Mayans could have been devastating."