Maya Scholar Debunks World-Ending Myth

Maya Scholar Debunks World-Ending Myth

  10:58:00 AM    Science Lover

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As we hurtle toward the end of 2012, the conversation about a certain date with roots in an ancient Maya calendar has reached a fever pitch.

David Stuart discusses the new inscriptions with colleagues from Tulane University and Universidad del Valle de Guatemala. Seated left to right: Marcello Canuto (Tulane), Stuart, Tomás Barrientos (UVG), Jocelyn Ponce (UVG). (Credit: Image courtesy of University of Texas at Austin)

Dec. 21, 2012, has taken over popular culture this year: It's been the subject of movies, books and news shows. The date and its supposed prophecy that the world will come to an end has been the subject of water cooler conversations and international media attention.

But the truth regarding the date, according to renowned Maya scholar and University of Texas at Austin art history professor David Stuart, is that the day is indeed meaningful -- but not in the way you might think.

"The Maya never actually predicted the end of times," says Stuart, who recently won a UNESCO medal for his lifetime contributions to the study of ancient Maya culture and archaeological sites, including UNESCO World Heritage Sites. "In the Maya scheme of time, the approaching date was thought to be the turn of an important cycle, or as they put it, the end of 13 bak'tuns. The thing is, there are many more bak'tuns still to come."

Earlier this year, Stuart was working with colleagues at the ruins of La Corona in the Guatemalan jungle, where they excavated many inscribed stones that had been part of a staircase. As the world's leading epigrapher of Maya script, Stuart was brought in to decipher the 56 glyphs carved into the stones. He discovered 200 years of political history and, to his surprise, the second known reference in Maya culture to the so-called end date of Dec. 21, 2012.

But despite the popular misconception, the date doesn't predict the end of times. Rather, it was intended to promote continuity during a time of crisis.

"The hieroglyphs emphasized seventh century history and politics, linking the reign of an ancient king to the turn of the 13th bak'tun many centuries later," Stuart explains. "The point was to associate the divine king's time on the throne to time on a cosmic scale.

"The monument commemorated a royal visit to La Corona in AD 696 by the most powerful Maya ruler of that time, a few months after his defeat by a longstanding rival in AD 695," said Stuart. "This ruler was visiting allies and allaying their fears after his defeat. It was a time of great political turmoil in the Maya region, and this king felt compelled to allude to a larger cycle of time that happens to end in 2012."

Rather than prophesy, the 2012 reference served to place this king's troubled reign and accomplishments into a larger cosmological framework. In times of crisis, the ancient Maya used their calendar to promote continuity and stability.

Assuming 21st century soothsayers are incorrect about the impending end of the world, Stuart's research will continue in 2013, starting in January with the Maya Meetings, an international conference held, alternately, in Austin and Antigua, Guatemala, each year. Stuart has served as director of the event since 2004, and this year it is a family affair. Stuart's father, George E. Stuart, will be the keynote speaker at this year's meeting, which will be in Austin.

The elder Stuart was hired as a cartographer for the National Geographic Society and remained on staff for nearly 40 years working in a variety of capacities, including as editor for archaeology of National Geographic Magazine and chairman of the Committee for Research and Exploration. He founded the Center for Maya Research in 1984.

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CO2: Missing Link to Past Climate Changes

CO2: Missing Link to Past Climate Changes

  8:15:00 PM    Science Lover

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Increasingly, the Earth's climate appears to be more connected than anyone would have imagined. El Nino, the weather pattern that originates in a patch of the equatorial Pacific, can spawn heat waves and droughts as far away as Africa.

Sedimentary cores taken from the ocean floor in four l
ocations show that climate patterns in the tropics have 
mirrored Ice Age cycles for the last 2.7 million years 
and that carbon dioxide has played the leading role in 
determining global climate patterns. Cores from site 806 
were used as controls. (Credit: Timothy Herbert, 
Brown University)

Now, a research team led by Brown University has established that the climate in the tropics over at least the last 2.7 million years changed in lockstep with the cyclical spread and retreat of ice sheets thousands of miles away in the Northern Hemisphere. The findings appear to cement the link between the recent Ice Ages and temperature changes in tropical oceans. Based on that new link, the scientists conclude that carbon dioxide has played the lead role in dictating global climate patterns, beginning with the Ice Ages and continuing today.

"We think we have the simplest explanation for the link between the Ice Ages and the tropics over that time and the apparent role of carbon dioxide in the intensification of Ice Ages and corresponding changes in the tropics," said Timothy Herbert, professor of geological sciences at Brown and the lead author of the paper in Science.

"It certainly supports the idea of global sensitivity of climate to carbon dioxide as the first order of control on global temperature patterns," Herbert added, "but we don't know why. The answer lies in the ocean, we're pretty sure."

The research team, including scientists from Luther College in Iowa, Lafayette College in Pennsylvania, and the University of Hong Kong, analyzed cores taken from the seabed at four locations in the tropical oceans: the Arabian Sea, the South China Sea, the eastern Pacific and the equatorial Atlantic Ocean.

They decided to zero in on tropical ocean surface temperatures because these vast bodies, which make up roughly half of the world's oceans, in large measure orchestrate the amount of water in the atmosphere and thus rainfall patterns worldwide, as well as the concentration of water vapor, the most prevalent greenhouse gas.

Looking at the chemical remains of tiny marine organisms that lived in the sunlit zone of the ocean, the scientists were able to extract the surface temperature for the oceans for the last 3.5 million years, well before the beginning of the Ice Ages. Beginning about 2.7 million years ago, the geologists found that tropical ocean surface temperatures dropped by 1 to 3 degrees Celsius (1.8 to 5.4 degrees Fahrenheit) during each Ice Age, when ice sheets spread in the Northern Hemisphere and significantly cooled oceans in the northern latitudes. Even more compelling, the tropics also changed when Ice Age cycles switched from roughly 41,000-year to 100,000-year intervals.

"The tropics are reproducing this pattern both in the cooling that accompanies the glaciation in the Northern Hemisphere and the timing of those changes," Herbert said. "The biggest surprise to us was how similar the patterns looked all across the tropics since about 2.7 million years ago. We didn't expect such similarity."

Climate scientists have a record of carbon dioxide levels for the last 800,000 years -- spanning the last seven Ice Ages -- from ice cores taken in Antarctica. They have deduced that carbon dioxide levels in the atmosphere fell by about 30 percent during each cycle, and that most of that carbon dioxide was absorbed by high-latitude oceans such as the North Atlantic and the Southern Ocean. According to the new findings, this pattern began 2.7 million years ago, and the amount of atmospheric carbon dioxide absorbed by the oceans has intensified with each successive Ice Age. Geologists know the Ice Ages have gotten progressively colder -- leading to larger ice sheets -- because they have found debris on the seabed of the North Atlantic and North Pacific left by icebergs that broke from the land-bound sheets.

"It seems likely that changes in carbon dioxide were the most important reason why tropical temperatures changed, along with the water vapor feedback," Herbert said.

Herbert acknowledges that the team's findings leave important questions. One is why carbon dioxide began to play a major role when the Ice Ages began 2.7 million years ago. Also left unanswered is why carbon dioxide appears to have magnified the intensity of successive Ice Ages from the beginning of the cycles to the present. The researchers do not understand why the timing of the Ice Age cycles shifted from roughly 41,000-year to 100,000-year intervals.

Contributing authors are Laura Cleaveland Peterson at Luther College, Kira Lawrence at Lafayette College and Zhonghui Liu at the University of Hong Kong. The U.S. National Science Foundation and the Evolving Earth Foundation funded the research. The cores came from the Ocean Drilling Program, sponsored by the NSF, and the Integrated Ocean Drilling Program.

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