(News & Editorial / Drought, Part 1 – Before 2012)
Mayan Drought & the developing US perma-drought of 2009+
A. Archaeologists uncover largest ancient dam built by Maya in Central America
July 16, 2012, Provided by University of Cincinnati
Pasted from <http://phys.org/news/2012-07-archaeologists-uncover-largest-ancient-built.html#>
[This image shows excavation of the dam identified by the UC-led team. A collapsed sluice gate is outlined in red. Credit: University of Cincinnati researchers]
Recent excavations, sediment coring and mapping by a multi-university team led by the University of Cincinnati at the pre-Columbian city of Tikal, a paramount urban center of the ancient Maya, have identified new landscaping and engineering feats, including the largest ancient dam built by the Maya of Central America.
That dam – constructed from cut stone, rubble and earth – stretched more than 260 feet in length, stood about 33 feet high and held about 20 million gallons of water in a man-made reservoir.
These findings on ancient Maya water and land-use systems at Tikal, located in northern Guatemala, are scheduled to appear this week in the Proceedings of the National Academy of Sciences (PNAS) in an article titled “Water and Sustainable Land Use at the Ancient Tropical City of Tikal, Guatemala.” The research sheds new light on how the Maya conserved and used their natural resources to support a populous, highly complex society for over 1,500 years despite environmental challenges, including periodic drought.
The paper is authored by Vernon Scarborough, UC professor of anthropology; Nicholas Dunning, UC professor of geography; archaeologist Kenneth Tankersley, UC assistant professor of anthropology; Christopher Carr, UC doctoral student in geography; Eric Weaver, UC doctoral student in geography; Liwy Grazioso of the Universidad de San Carlos de Guatemala; Brian Lane, former UC master’s student in anthropology now pursuing doctoral studies at the University of Hawaii; John Jones, associate professor of anthropology, Washington State University; Palma Buttles, technical staff senior member, SEI Carnegie Mellon University; Fred Valdez, professor of anthropology, University of Texas-Austin; and David Lentz, UC professor of biology.
Starting in 2009, the UC team was the first North American group permitted to work at the Tikal site core in more than 40 years.
What was once thought to be a sluice is outlined in red and is now filled with slump-down debriss.
Detailed in the latest findings by the UC-led efforts are:
• The largest ancient dam built by the ancient Maya of Central America
• Discussion on how reservoir waters were likely released
• Details on the construction of a cofferdam needed by the Maya to dredge one of the largest reservoirs at Tikal
• The presence of ancient springs linked to the initial colonization of Tikal
• Use of sand filtration to cleanse water entering reservoirs
• A “switching station” that accommodated seasonal filling and release of water
• Finding of the deepest, rock-cut canal segment in the Maya lowlands
According to UC’s Scarborough, “The overall goal of the UC research is to better understand how the ancient Maya supported a population at Tikal of perhaps 60,000 to 80,000 inhabitants and an estimated population of five million in the overall Maya lowlands by AD 700.”
He added, “That is a much higher number than is supported by the current environment. So, they managed to sustain a populous, highly complex society for well over 1,500 years in a tropical ecology. Their resource needs were great, but they used only stone-age tools and technology to develop a sophisticated, long-lasting management system in order to thrive.”
Water collection and storage were critical in the environment where rainfall is seasonal and extended droughts not uncommon. And so, the Maya carefully integrated the built environment – expansive plazas, roadways, buildings and canals – into a water-collection and management system. At Tikal, they collected literally all the water that fell onto these paved and/or plastered surfaces and sluiced it into man-made reservoirs. For instance, the city’s plastered plaza and courtyard surfaces and canals were canted in order to direct and retain rainwater runoff into these tanks.
In fact, by the Classic Period (AD 250-800), the dam (called the Palace Dam) identified by the UC-led team was constructed to contain the waters that were now directed from the many sealed plaster surfaces in the central precinct. It was this dam on which the team focused its latest work, completed in 2010. This gravity dam presents the largest hydraulic architectural feature known in the Maya area. In terms of greater Mesoamerica, it is second in size only to the huge Purron Dam built in Mexico’s Tehuacan Valley sometime between AD 250-400.
Said Scarborough, “We also termed the Palace Dam at Tikal the Causeway Dam, as the top of the structure served as a roadway linking one part of the city to another. For a long time, it was considered primarily a causeway, one that tourists coming to the site still use today. However, our research now shows that it did double duty and was used as an important reservoir dam as well as a causeway.”
[At rights is a view of a Maya-built canal. Pictured is Guatemalan researcher Liwy Grazioso, who has participated in the work by a UC-led team. Credit: University of Cincinnati researchers]
Another discovery by the UC-led team: To help purify water as it sluiced into the reservoir tanks via catchment runoff and canals, the Maya employed deliberately positioned “sand boxes” that served to filter the water as it entered into the reservoirs. “These filtration beds consisted of quartz sand, which is not naturally found in the greater Tikal area. The Maya of Tikal traveled at least 20 miles (about 30 kilometers) to obtain the quartz sand to create their water filters. It was a fairly laborious transportation effort. That speaks to the value they placed on water and water management,” said UC’s Nicholas Dunning.
According to UC’s Ken Tankersley, “It’s likely that the overall system of reservoirs and early water-diversion features, which were highly adaptable and resilient over a long stretch, helped Tikal and some other centers survive periodic droughts when many other settlement sites had to be abandoned due to lack of rainfall.”
UC paleoethnobotanist David Lentz explained that the sophisticated water management practiced by the ancient Maya impacted the availability of food, fuel, medicinal plants and other necessities. He said, “Water management by the Maya included irrigation, which directly impacted how many people could be fed and overall population growth. Accordingly, it is essential to understand the array of canals and reservoirs at Tikal, which conserved water during the annual dry season and controlled floodwaters during the rainy months. These practices allowed the Tikal Maya to sustain relatively high population densities for several centuries. As it evolved, this system of reservoirs was largely dependent on rainfall for recharging. With the onset of the 9th century droughts however, water supplies dwindled, causing the resource base and social fabric of the Tikal Maya to come under considerable stress. These developments may well have contributed to the abandonment of the city.”
Of significance to Scarborough and the entire team are the potential lessons that can be gleaned from identifying a water system like that at ancient Tikal. Said Scarborough, “Water management in the ancient context can be dismissed as less relevant to our current water crisis because of its lack of technological sophistication. Nevertheless, in many areas of the world today, the energy requirements for even simple pumping and filtering devices – to say nothing about replacement-part acquisition – challenges access to potable sources. Tropical settings can be especially difficult regions because of high infectious disease loads borne by unfiltered water schemes. The ancient Maya, however, developed a clever rainwater catchment and delivery system based on elevated, seasonally charged reservoirs positioned in immediate proximity to the grand pavements and pyramidal architecture of their urban cores. Allocation and potability were developmental concerns from the outset of colonization. Perhaps the past can fundamentally inform the present, if we, too, can be clever.
B. The Fall of the Maya: ‘They Did it to Themselves’
October 7, 2009, Science@NASA, by Dauna Coulter
Read more at: http://phys.org/news174152911.html#jCp
For 1200 years, the Maya dominated Central America. At their peak around 900 A.D., Maya cities teemed with more than 2,000 people per square mile — comparable to modern Los Angeles County. Even in rural areas the Maya numbered 200 to 400 people per square mile. But suddenly, all was quiet. And the profound silence testified to one of the greatest demographic disasters in human prehistory — the demise of the once vibrant Maya society.
[Photo at left: Mayan ruins in Guatemala.]
What happened? Some NASA-funded researchers think they have a pretty good idea. “They did it to themselves,” says veteran archeologist Tom Sever.
“The Maya are often depicted as people who lived in complete harmony with their environment,’ says PhD student Robert Griffin. “But like many other cultures before and after them, they ended up deforesting and destroying their landscape in efforts to eke out a living in hard times.”
A major drought occurred about the time the Maya began to disappear. And at the time of their collapse, the Maya had cut down most of the trees across large swaths of the land to clear fields for growing corn to feed their burgeoning population. They also cut trees for firewood and for making building materials.
“They had to burn 20 trees to heat the limestone for making just 1 square meter of the lime plaster they used to build their tremendous temples, reservoirs, and monuments,” explains Sever.
He and his team used computer simulations to reconstruct how the deforestation could have played a role in worsening the drought. They isolated the effects of deforestation using a pair of proven computer climate models: the PSU/NCAR mesoscale atmospheric circulation model, known as MM5, and the Community Climate System Model, or CCSM.
“We modeled the worst and best case scenarios: 100 percent deforestation in the Maya area and no deforestation,” says Sever. “
The results were eye opening. Loss of all the trees caused a 3-5 degree rise in temperature and a 20-30 percent decrease in rainfall.” The results are telling, but more research is needed to completely explain the mechanisms of Mayan decline. Archeological records reveal that while some Maya city-states did fall during drought periods, some survived and even thrived. “
We believe that drought was realized differently in different areas,” explains Griffin. “We propose that increases in temperature and decreases in rainfall brought on by localized deforestation caused serious enough problems to push some but not all city-states over the edge.” EnlargeA deadly cycle of drought, warming and deforestation may have doomed the Maya. The Maya deforested through the use of slash-and-burn agriculture – a method still used in their old stomping grounds today, so the researchers understand how it works.
“We know that for every 1 to 3 years you farm a piece of land, you need to let it lay fallow for 15 years to recover. In that time, trees and vegetation can grow back there while you slash and burn another area to plant in.”
But what if you don’t let the land lay fallow long enough to replenish itself? And what if you clear more and more fields to meet growing demands for food? “
We believe that’s what happened,” says Griffin. “The Maya stripped large areas of their landscape bare by over-farming.”
Not only did drought make it difficult to grow enough food, it also would have been harder for the Maya to store enough water to survive the dry season. “The cities tried to keep an 18-month supply of water in their reservoirs,” says Sever. “For example, in Tikal there was a system of reservoirs that held millions of gallons of water. Without sufficient rain, the reservoirs ran dry.” Thirst and famine don’t do much for keeping a populace happy. The rest, as the saying goes, is history. “
In some of the Maya city-states, mass graves have been found containing groups of skeletons with jade inlays in their teeth – something they reserved for Maya elites – perhaps in this case murdered aristocracy,” he speculates.
No single factor brings a civilization to its knees, but the deforestation that helped bring on drought could easily have exacerbated other problems such as civil unrest, war, starvation and disease.
Many of these insights are a result of space-based imaging, notes Sever. “By interpreting infrared satellite data, we’ve located hundreds of old and abandoned cities not previously known to exist. The Maya used lime plaster as foundations to build their great cities filled with ornate temples, observatories, and pyramids. Over hundreds of years, the lime seeped into the soil. As a result, the vegetation around the ruins looks distinctive in infrared to this day.”
Space technology is revolutionizing archeology,” he concludes. “We’re using it to learn about the plight of ancients in order to avoid a similar fate today.”
C. Global Ocean Surface Temperature Warmest On Record For June
ScienceDaily (July 27, 2009) — The world’s ocean surface temperature was the warmest on record for June, breaking the previous high mark set in 2005, according to a preliminary analysis by NOAA’s National Climatic Data Center in Asheville, N.C. Additionally, the combined average global land and ocean surface temperature for June was second-warmest on record. The global records began in 1880.
Global Climate Statistics
The combined global land and ocean surface temperature for June 2009 was the second warmest on record, behind 2005, 1.12 degrees F (0.62 degree C) above the 20th century average of 59.9 degrees F (15.5 degrees C) [1.12F rise + 59.9 average= 61.02F, 2009 combined land and oceans].
Separately, the global ocean surface temperature for June 2009 was the warmest on record, 1.06 degrees F (0.59 degree C) above the 20th century average of 61.5 degrees F (16.4 degrees C).[1.06 rise + 61.5F average = 62.56F 2009 oceans]
[Now, fast forward 3 years to the present; see the growing effects of “the warmest global ocean surface temperature” from July 2009. Mr Larry]
D. Punishing drought in Midwest shows no sign of abating
17 July 2012, Reuters, By Ernest Scheyder
Pasted from <http://news.yahoo.com/punishing-drought-midwest-shows-no-sign-abating-012249337.html>
(Reuters) – Broiling heat blanketed much of the Midwest again on Tuesday, exacerbating the region’s worst drought in more than 50 years and devastating corn, soy and other vital crops.
Across the country’s agricultural heartland, elected officials met with farmers and ranchers affected by the growing disaster promising government relief.
In Missouri, Governor Jay Nixon announced on Tuesday that all 114 counties in the state have been designated as natural disaster areas due to the drought, making farmers eligible for government loans or other assistance. Before Tuesday, 17 counties had received disaster status.
In Iowa, Governor Terry Branstad convened a hearing to discuss the drought and its effect on the state’s pork industry, which relies heavily on corn feed.
“It’s important that we do all we can to help people through this difficult time,” Branstad told local radio station KILJ. “And obviously more rain would help.”
Although weather forecasters said some parts of the parched region might get some rain next week and help pull corn prices off near-record highs, analysts slashed their forecasts for U.S. corn production by another 7 percent on Tuesday, a Reuters poll found.
From Chicago to St. Louis to Omaha, Nebraska, temperatures eclipsed 100 Fahrenheit (37.8 Celsius) and the National Weather Service issued heat advisories across Midwest and mid-Atlantic states.
Many of the heat advisories don’t expire until next week. Temperatures in Kansas City, Kansas, for instance, are expected to hit 104 F (40 C) on Wednesday. In Topeka, the intense heat is drying up soil so far beneath the surface that water lines are cracking.
So far this month, 2,202 heat records have been broken across the United States and another 787 tied, according to the National Climatic Data Center.
Another 14 U.S. cities set new record highs by 8 p.m. EDT (0000 GMT) on Tuesday, according to Accuweather.com, including St. Louis, Milwaukee, Detroit and Syracuse, which all topped out above 100 F.
Those temperatures have contributed to the worst drought since 1956, the National Oceanic and Atmospheric Administration said in a report posted on its website.
FROM CRISIS TO HORROR STORY
About 55 percent of the contiguous United States is in a drought, just as corn plants should be pollinating, a period when adequate moisture is crucial. The United States ships more than half of all world exports of corn, which is made into dozens of products, from starch and ethanol to livestock feed.
“We’re moving from a crisis to a horror story,” said Purdue University agronomist Tony Vyn. “I see an increasing number of fields that will produce zero grain.”
The soonest rain is expected in the Midwest is the middle of next week, said Jason Nicholls, meteorologist for AccuWeather. [Stunted corn grows next to a cattle feed lot in Springfield, rural Omaha, Neb. on Tuesday. The drought gripping the United States is the widest since 1956.
The new forecast calls for rains of 0.2 to 0.7 inch (5 mm to 18 mm) around the region, up from earlier outlooks of 0.1 to 0.6 inch.
The dry weather and intense heat likely will continue through August, further damaging the corn crop, AccuWeather said.
Corn prices are at 13-month highs and have surged 45 percent this summer, with analysts expecting the lingering drought to result in the smallest U.S. corn crop in five years.
As the worst drought since the Eisenhower administration begins to expand to the northern and western Midwest, areas that had previously been spared, analysts are slashing corn yield estimates by the hour.
“We need soaking rains now. We need two-to-three-inches and that’s not in the forecast,” AgResource Co analyst Dan Basse said.
EFFECT ON FOOD PRICES
In April concern mounted that near-record spring corn plantings would sharply increase supply and push corn prices below $5 per bushel.
Now, because of the drought, corn prices are flirting with $8 per bushel, and that could boost food prices.
With much of the Midwest pasture laid waste by the drought and ranchers facing climbing feed costs, many ranchers have begun liquidating their herds, which could translate into higher prices for meat next year.
“Based on my conversations with producers, I would say 75 percent of the corn crop in the heart of the drought is beyond help,” said grains analyst Mike Zuzolo, president of Global Commodity Analytics & Consulting in Lafayette, Indiana.
Weather problems were also reported in Eastern Europe and Asia, mirroring drought that dented Argentina and Brazil’s last harvest.
Black Sea grain producer Kazakhstan was preparing for a below-average crop this year due to an “alarming” drought in the country’s main growing regions.
The United Nations food agency said earlier this month that the U.S. drought was expected to see global food prices snap three months of declines in its July figures.
The drought is even harming equipment makers. Shares of Deere & Co, the world’s largest maker of tractors and combines, fell on Tuesday after a JPMorgan analyst said the U.S. drought was likely to harm sales in 2013.
E. Global Temperature in 2011, Trends, and Prospects
18 January 2012, by James Hansen, Reto Ruedy, Makiko Sato and Ken Lo
…Because of the ocean’s thermal inertia, global temperature change caused by solar variability lags solar irradiance by about 18 months. Thus the influence of the sun in 2011 continued to be a cooling effect. However, the sun’s influence will change rapidly to a warming effect over the next 3-5 years…
[During January of this year, Columbia University researchers were predicting global warming to increase over the next 3-5 years–2012, 2013, 2014, 2015, 2016. So if we’re mildly upset with the heat, crop reports and grocery prices this fall, imagine the price-world social situation over, minimally, the next 2 years. – Mr Larry]
2011 was only the ninth warmest year in the GISS analysis of global temperature change, yet nine of the ten warmest years in the instrumental record (since 1880) have occurred in the 21st century. The past year has been cooled by a moderately strong La Nina. The 5-year (60-month) running mean global temperature hints at a slowdown in the global warming rate during the past few years. However, the cool La Nina phase of the cyclically variable Southern Oscillation of tropical temperatures has been dominant in the past three years, and the deepest solar minimum in the period of satellite data occurred over the past half dozen years. We conclude that the slowdown of warming is likely to prove illusory, with more rapid warming appearing over the next few years.”