Why the Maya Fell: Climate Change, Conflict—And a Trip to the Beach?
Latest evidence hints at a cautionary tale for modern civilization, expert says.
Maya Empire, seemingly swallowed by the jungle after centuries of urban, cultural, intellectual, and agricultural evolution.
In a wet period, Maya farms thrived, and an empire flowered, studies say.
What went wrong? The latest discoveries point not to a cataclysmic eruption, quake, or plague but rather to climate change. And faced with the fallout, one expert says, the Maya may have packed up and gone to the beach.
But first came the boom years, roughly A.D. 300 to 660. At the beginning of the so-called Classic Maya period, some 60 Maya cities—each home to between 60,000 and 70,000 people—sprang up across much of modern-day Guatemala, Belize, and Mexico's Yucatán Peninsula. (Explore an interactive map of key Maya sites.)
Surrounded by pyramids, plazas, ball courts, and government buildings, the urban Maya discussed philosophy, developed an accurate solar-year calendar, and relished a thick, bitter beverage made from cacao beans: the world's first hot chocolate.
Farmers, too, were riding high, turning hillsides into terraced fields to feed the burgeoning population.
Then came the bust, a decline that lasted at least two centuries. By 1100 the residents of once thriving Maya cities seem to have just up and left. But where did they flee to, and why?
In the 19th century, when explorers began discovering the overgrown ruins of "lost cities," theorists imagined an immense volcanic eruption or earthquake or superstorm—or maybe an empire-wide pandemic. (Related: "Maya Mystery Solved by 'Important' Volcanic Discovery?")
But today scientists generally agree that the Maya collapse has many roots, all intertwined—overpopulation, warfare, famine, drought. At the moment, the hottest field of inquiry centers on climate change, perhaps of the Maya's own doing.
(Also see "Climate Change May Have Killed Off Maya Civilization, Study Says.")
Flowering With the Rain
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.
(Take a Maya quiz.)
A Cautionary Tale?
The collapse, though, wasn't exactly all natural. To some extent, the Maya may have designed their own decline.
"There were tens of millions of people in the area, and they were building cities and farms at the expense of the forest," climate scientist Benjamin I. Cook said.
Widespread deforestation reduced the flow of moisture from the ground to the atmosphere, interrupting the natural rain cycle and in turn reducing precipitation, says Cook, of NASA's Goddard Institute for Space Studies and the Lamont-Doherty Earth Observatory.
According to computer simulations Cook ran for a study published in Geophysical Research Letters this past August, the localized drying decreased atmospheric moisture by 5 to 15 percent annually. Even a 10 percent decrease is considered an environmental catastrophe, he says.
Add this to the broader drying trend and the situation becomes dire—a cautionary tale for modern society, according to Cook. Today, as more and more forestland is turned into farms and cities, and as global temperatures continue to rise, we may risk the same fate that befell the Maya, he says.
But, according to Arizona State University professor of environment and society B.L. Turner, "that's the kind of oversimplification we're trying to get away from. The Mayan situation is not applicable today—our society is just so radically different now."
Lure of the Beach
In a study published in August by the journal Proceedings of the National Academy of Sciences, Turner attempts to correct some common misconceptions, beginning with the idea that Maya civilization vanished after the conquistadores arrived.
"It didn't cease to exist; there are still today Mayan people in the area. The culture, the traditions have been maintained," he said. But the cities, historically, have not—and that's odd.
Throughout global history, he said, "rarely can you find a large sustained population that just left and never came back," Turner said. The closest analogue he can think of is the sudden, and final, abandonment of Cambodia's Angkor Wat complex in the 15th century.
Turner's study concludes that the natural environment recovered rather quickly after the dry centuries. Why, then, didn't the Maya reclaim their glorious cities?
Turner points to the coasts. Fleeing starving, warring inland cities, many Maya made a beeline for the shore. Trade also shifted, from overland paths to coastal routes, he suggests.
With life relatively comfortable on the coast, the inland Mayan cities may have simply been forgotten, Turner says. No catastrophic earthquake, no plague, no curse, but rather a gradual migration to the beach, where life was a bit mellower.
That is, until the Spanish arrived.
More: See National Geographic pictures of Maya ruins and artifacts >>
Maya Collapse explained as 100 year drought
An aerial view of the coral reef and deep cave that make up the famous diving spot of the Blue Hole in the Caribbean Sea, off the coast of Belize.
Belize's Famous 'Blue Hole' Reveals Clues to the Maya's Demise
The ancient Mayan civilization collapsed due to a century-long drought, new research suggests.
Minerals taken from Belize's famous underwater cave, known as the Blue Hole, as well as lagoons nearby, show that an extreme drought occurred between A.D. 800 and A.D. 900, right when the Mayan civilization disintegrated. After the rains returned, the Mayans moved north — but they disappeared again a few centuries later, and that disappearance occurred at the same time as another dry spell, the sediments reveal. [In Photos: Stunning Sinkholes]
Although the findings aren't the first to tie a drought to the Mayan culture's demise, the new results strengthen the case that dry periods were indeed the culprit. That's because the data come from several spots in a region central to the Mayan heartland, said study co-author André Droxler, an Earth scientist at Rice University.
Rise and decline
From A.D. 300 to A.D. 700, the Mayan civilization flourished in the Yucatan peninsula. These ancient Mesoamericans built stunning pyramids, mastered astronomy, and developed both a hieroglyphic writing system and a calendar system, which is famous for allegedly predicting that the world would end in 2012.
But in the centuries after A.D. 700, the civilization's building activities slowed and the culture descended into warfare and anarchy. Historians have speculatively linked that decline with everything from the ancient society's fear of malevolent spirits to deforestation completed to make way for cropland to the loss of favored foods, such as the Tikal deer.
The evidence for a drought has been growing in recent years: Since at least 1995, scientists have been looking more closely at the effects of drought. A 2012 study in the journal Science analyzed a 2,000-year-old stalagmite from a cave in southern Belize and found that sharp decreases in rainfall coincided with periods of decline in the culture. But that data came from just one cave, which meant it was difficult to make predictions for the area as a whole, Droxler said.
The main driver of this drought is thought to have been a shift in the intertropical convergence zone (ITCZ), a weather system that generally dumps water on tropical regions of the world while drying out the subtropics. During summers, the ITCZ pelts the Yucatan peninsula with rain, but the system travels farther south in the winter. Many scientists have suggested that during the Mayan decline, this monsoon system may have missed the Yucatan peninsula altogether.
To look for signs of drought, the team drilled cores from the sediments in the Blue Hole of Lighthouse lagoon, as well one in the Rhomboid reef. The lagoons surrounded on all sides by thick walls of coral reef. During storms or wetter periods, excess water runs off from rivers and streams, overtops the retaining walls, and is deposited in a thin layer at the top of the lagoon. From there, all the sediments from these streams settle to the bottom of the lagoon, piling on top of each other and leaving a chronological record of the historical climate.
"It's like a big bucket. It's a sediment trap," Droxler told Live Science.
Droxler and his colleagues analyzed the chemical composition of the cores, in particular the ratio of titanium to aluminum. When the rains fall, it eats away at the volcanic rocks of the region, which contain titanium. The free titanium then sweeps into streams that reach the ocean. So relatively low ratios of titanium to aluminum correspond to periods with less rainfall, Droxler said.
The team found that during the period between A.D. 800 and A.D. 1000, when the Maya civilization collapsed, there were just one or two tropical cyclones every two decades, as opposed to the usual five or six. After that, the Maya moved north, building at sites such as Chichen Itza, in what is now Mexico.
But the new results also found that between A.D. 1000 and A.D. 1100, during the height of the Little Ice Age, another major drought struck. This period coincides with the fall of Chichen Itza.
The findings strengthen the case that drought helped usher in the long decline of the Mayan culture.
"When you have major droughts, you start to get famines and unrest," Droxler said.
The Collapse Explained
"The ancient Mayan civilization collapsed due to a century-long drought," - that's what new research suggests. According to a study by archaeologists at Rice University, sediments found in the Belize Blue Hole near the center of Lighthouse Reef show that extreme drought may be the leading cause of the civilization's collapse.
The director of the Institute of Archaeology, Dr. John Morris told us via phone that this development complements the research he and his team are conducting in the Caves here in Belize and that this theory is only one of many.
Dr. John Morris
"There are many theories that explain the collapse of the ancient Maya civilization and one of them is that of environmental degradation or in some sense severe dry period of drought that affected the Maya quite considerably. It's one of several theories and one that has been examined quite recently in detail. The evidence that we are acquiring comes from core deposits that we retrieve from lagoons and lakes and also from tests done on stalagmites in caves and primarily because what those show is that running through test on the stalagmites, it shows that a severe dry period took place sometime around that same period between 700 and 900 AD and the evidence is remarkable because those caves for example the one in the blue hole and also when you look at the coring done at Lake Peten in Tikal, it shows also too that there was significant dry periods."
According to Morris the period of drought is recorded to have occurred between 700 and 900 AD.
Researchers found that during this period, there were only one or two tropical cyclones every two decades, as opposed to the usual five or six.
Environmental conditions and weather patterns are also being studied based on this evidence to validate the drought theory.