Why the once great Maya civilization withered away is still a matter of debate among historians, archaeologists, and geoscientists. The leading theory is that the Maya suffered a series of severe droughts around 800–1100. New evidence suggests there may have been another reason: severe tropical storms.
One source for finding undisturbed sediments is blue holes, marine sinkholes into which sediments are continually deposited. Generally, the sediments in deposition layers are smooth. But when a large storm passes by, it rakes up and deposits coarse particles. Because of the structure of a blue hole, material can be deposited but cannot get out, allowing the feature to act as a near-perfect record of ancient storms.
Now Dominik Schmitt of Goethe University in Frankfurt, Germany, and colleagues have reconstructed past storms in the region going back 2,000 years. The researchers recovered and studied an 8.5-meter-long sediment core from the Great Blue Hole on Lighthouse Reef off the coast of Belize.
The sediments also revealed something else. “The tropical cyclone activity of the southwestern Caribbean generally shifted from a less active (100–900 CE) to a more active state (900 CE to modern),” said Schmitt. The shift happened right around the time when the Maya civilization was in decline.
The Classic Maya civilization, which once occupied most of the Yucatán Peninsula, began to wane starting in the late 800s. During the next century, great Maya cities like Copán (in what is now Honduras) and Tikal (in what is now Guatemala) were abandoned.
Climate change is thought to have been a primary driver of this collapse. The leading theory suggests that a series of severe and prolonged droughts plagued the Yucatán Peninsula, which may have reduced the availability of fresh water and decreased agricultural productivity.
In addition to drought, the Maya may have had to contend with increased and more unpredictable Caribbean cyclones. The Great Blue Hole sediment core showed five exceptionally thick layers—15 to 30 centimeters—deposited between 700 and 1150. These layers suggest extremely intense cyclones; for comparison, the deposition layer left by Hurricane Hattie, a Category 5 hurricane that passed over the same area in 1961, was just 4 centimeters thick.
Two of the ancient cyclones struck during drought periods, and the others struck just before and after severe droughts. It’s likely these cyclone landfalls destroyed Maya infrastructure, caused coastal flooding and crop failures, and added to the environmental stress of the intensive drought phases.
https://www.smithsonianmag.com/science-nature/severe-cyclones-may-have-played-role-maya-collapse-180975717/
