Transcript Deline of Angkor factors

Deline of Angkor factors
http://www.msnbc.msn.com/id/45857260/ns/technology_and_science-science/t/drought-leddemise-ancient-city-angkor/
updated 1/3/2012 10:57:28 AM ET
By Charles Choi
great city of Angkor
• The great city of Angkor in Cambodia, first
established in the ninth century, was the capital
of the Khmer Empire, the major player in
southeast Asia for nearly five centuries. It
stretched over more than 385 square miles
(1,000 square kilometers), making it the most
extensive urban complex of the preindustrial
world. In comparison, Philadelphia covers 135
square miles (350 sq. km), while Phoenix
sprawls across more than 500 square miles
(1,300 sq. km), not including the huge suburbs.
Suggested causes
war and land overexploitation but evidence suggests that prolonged
droughts might have been linked to the decline of Angkor
• Suggested causes for the fall of the Khmer
Empire in the late 14th to early 15th
centuries have included war and land
overexploitation. However, recent
evidence suggests that prolonged
droughts might have been linked to the
decline of Angkor — for instance, tree
rings from Vietnam suggest the region
experienced long spans of drought
interspersed with unusually heavy rainfall.
Complex network of channels, moats, and
embankments and reservoirs known as barays
• Angkor possessed a complex network of
channels, moats, and embankments and
reservoirs known as barays to collect and store
water from the summer monsoons for use in rice
paddy fields in case of drought. To learn more
about how the Khmer managed their water,
southwest corner of the largest Khmer reservoir,
the West Baray, which could hold 1.87 billion
cubic feet (53 million cubic meters) of water,
more than 20 times the amount of stone making
up the Great Pyramid at Giza.
Samples from across the greater Angkor region by
researcher Mary Beth Day
• Also, to collect samples from across the greater
Angkor region, researcher Mary Beth Day, a
paleolimnologist at the University of Cambridge
in England, hired a "tuk-tuk" (motorized
rickshaw) driver, and was able to convince him
to drive her around the countryside, "often on
tracks that tuk-tuks probably aren't designed to
travel on," she recalled. "We nearly got stuck in
the sand a couple of times, but my driver was
remarkably accommodating given that he
probably thought I was crazy."
Sediment was deposited in the baray dropped to one-tenth
of what it was before
• The researchers deduced a 1,000-year-long climate
history of Angkor from the baray. They found at around
the time Angkor collapsed the rate at which sediment
was deposited in the baray dropped to one-tenth of what
it was before, suggesting that water levels fell
dramatically as well. The discovery "really emphasizes
how significant the events during this period must have
been," Day said.
• As both water levels and sediment deposits ebbed, the
ecology of the baray changed as well, with more bottomdwelling algae and floating plants coming into existence.
The ecological shift primarily to underline conditions in the
West Baray before and after Angkorian times.
• "The ecological shift primarily serves to
underline how environmental conditions in
the West Baray have been fundamentally
different since the 17th century, postcollapse, as compared to what the baray
was like during Angkorian times," Day
said.
Sudden and intense variations in
climate
• In the end, the water management systems of
the Khmer might have been insufficient to cope
with sudden and intense variations in climate.
[10 Ways Weather Changed History]
• Credit: NASA/NOAA GOES Project, Dennis
Chesters
• How Weather Changed History
• Laura Lee shares her Top 10 favorite storm
stories.
No 1 way weather changed history
•
•
Sunshine over Hiroshima
It was fine summer weather on Aug. 6, 1945 in Hiroshima. At 7:09 that morning, a weather reconnaissance plane
passed overhead and radioed back: "Cloud cover less than three-tenths. Advice: bomb primary." That is, the sky
was clear enough to drop the first nuclear weapon used in war. The lack of cloud cover sealed Hiroshima's fate,
and spared the back-up target. Even more dramatic was the effect of cloud cover on Kokura. On Aug. 8, the
second nuclear weapon was loaded into a B-29 called Bock's Car. But the skies were overcast over the primary
target, Kokura. Instead, the bomb was released over the backup target: Nagasaki.
No 2 way weather changed history
•
•
Hitler Invades Russia
Adolf Hitler, apparently not much of a student of history, decided to repeat Napoleon's attack on Moscow, and did
so all too well. In September, 1941, operation Typhoon (one of many military operations named for extreme
weather) swept into the Soviet Union. The German army was so confident it would win against Stalin's troops that
several units brought dress uniforms along for the victory march in Red Square. What they didn't bring along,
however, was winter clothing. Hitler's meteorologically assisted defeats in the Soviet Union, outside both Moscow
and in Stalingrad, were turning points in the war.
No 3 way weather changed history
•
•
Napoleon Invades Russia
In 1812, Napoleon assembled the largest army Europe had ever seen — more than 600,000 strong. His plan was
to march boldly into Russia. He was not at all worried that winter was approaching. Napoleon's confidence
appeared well-founded when his soldiers captured Moscow. They pillaged the city and stole jewels and furs as war
prizes, to present to their wives back home. Then the one thing that Napoleon had failed to consider became
abundantly clear. Russia can get very, very cold. As Napoleon's army marched away from the ruined city with their
spoils, temperatures fell to -40C. The soldiers fell to frostbite and starvation. In one 24-hour period, 50,000 horses
died from the cold. The men wrapped up in their wives' war prizes, but to no avail. Of the 600,000 men who
marched into Russia, only 150,000 would limp home. It was the beginning of the end for Napoleon's empire, and
heralded the emergence of Russia as a power in Europe.
No 4 way weather changed history
•
•
A Slave Revolt Washed Away
Aug. 30, 1800 might have been remembered as the day that thousands of slaves in Richmond,
Virginia followed a man named Gabriel and rose up against their masters, took the city armory
and freed all the slaves. Instead, a violent rainstorm kept the conspirators from gathering long
enough for word of the plot to get out.
No 5 way weather changed history
•
•
Hail Storms Speed the Onset of the French Revolution
In a country already suffering from an economic crisis because of debt it incurred
helping the American colonists in their war against England, a spring drought was
causing food prices to skyrocket when a final blow came in the form of a hailstorm,
which destroyed crops and laid waste to farms. The hungry populace was ready for
extreme change, and the French Revolution soon followed.
No 6 way weather changed history
•
•
Washington Lives to Fight Another Day
When George Washington became commander of the American army, it consisted of volunteers without uniforms
and often without weapons. The British army, by contrast, was a well-equipped fighting force. General Washington
could well have been defeated at the Battle of Long Island on Aug. 22, 1776 and we'd be eating tea and crumpets
today. Fortunately for U.S. history, a thick fog allowed the colonial forces to retreat unseen and to fight another
day.
No 7 way weather changed history
•
•
Charles XII invades Russia
In 1709, Swedish king Charles XII became the first great European invader to lead his men on a long march of
death and exhaustion through the Russian winter. The winter attrition of the mighty Swedish forces during "the
Great Northern War" had a great psychological impact and put the world on notice that Czar Peter I was a force to
be reckoned with.
No 8 way weather changed history
•
•
A "Protestant Wind" Destroys the Spanish Armada
The defeat of the Spanish Armada in 1588 has been called one of the most decisive battles in
Western civilization. Philip II of Spain sailed on the Protestant England of his sister-in-law
Elizabeth I, but the wind did not cooperate with his ambitions.
No 9 way weather changed history
•
•
The First Kamikaze
In the 13th century, Kublai Khan, leader of the Mongol Empire, set his sites on the conquest of Japan, but was
defeated by not one, but two monsoons. Shinto priests, who believed the storms were the result of prayer, called
them kamikaze or "divine wind".
No 10 way weather changed
history
•
•
Sea Breezes Save Western Culture
The survival of Greek culture, and consequently of Western Culture itself hung in the
balance during the Greco-Persian Wars. The Persian Empire, at the peak of its
strength, was poised to overrun mainland Greece itself. The Greek naval commander
Themistocles was able to turn the tides of war at the battle of Salamis in 480 BC by
using his knowledge of the winds.
Angkor can be an example of how technology isn't always sufficient to prevent major collapse
during times of severe instability (2 successive centuries of extreme environment conditions:
1362 to 1392 and 1415 to 1440, Angkor Decline in 1431)
• "Angkor can be an example of how technology isn't always
sufficient to prevent major collapse during times of severe
instability," Day told LiveScience. "Angkor had a highly
sophisticated water management infrastructure, but this
technologic advantage was not enough to prevent its collapse
in the face of extreme environmental conditions."
• "It's important to understand, however, that failure of the water
management network was not the sole reason for the downfall
of the Khmer Empire," Day added. "The collapse of Angkor was
a complex process brought about by several different factors
— social, political and environmental."
• The scientists detailed their findings online Jan. 2 in the
Proceedings of the National Academy of Sciences.
• Follow LiveScience for the latest in science news and
discoveries on Twitter @livescience and on Facebook.
Bayon temple, constructed by Angkorian King Jayavarman VII in the late 12th
century. The faces may be representations of Buddha, the bodhisattva
Lokesvara, Jayavarman VII, or a combination.
•
Bayon temple, constructed by Angkorian King Jayavarman VII in the late 12th century