Deline of Angkor factors

1. Deline of Angkor factors http://www.msnbc.msn.com/id/45857260/ns/technology_and_science-science/t/drought-led-demise-ancient-city-angkor/ updated 1/3/2012 10:57:28 AM ET By Charles Choi

2. 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.

3. 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.

4. 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.

5. 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."

6. 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 bottom-dwelling algae and floating plants coming into existence.

7. 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, post-collapse, as compared to what the baray was like during Angkorian times," Day said.

8. 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.

9. 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.

10. 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.

11. 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.

12. 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.

13. 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.

14. 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.

15. 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.

16. 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.

17. How Weather Changed History Laura Lee shares her Top 10 favorite storm stories. 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. 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. 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. 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. 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. 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. 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. 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. 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". 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. <img src="http://b.scorecardresearch.com/b?c1=2&c2=6035753&c3=6035753&c4=http://www.livescience.com/&c5=Technology - News&c6=&c15=C67BD3C1&cv=1.3&cj=1" style="display:none" width="0" height="0" alt="" /> HomeSpaceAnimalsHealthEnvironmentTechnologyCultureHistoryStrange NewsQuizzesVideoImagesTopicsShop Countdown: How Weather Changed History Laura Lee Date: 04 October 2006 Time: 02:41 PM ET inShare3 of 10 Intro10987654321More No 9 way weather changed history Credit: public domain, painting by Anige of Nepal 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". inShare3 • 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".

18. 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.

19. 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.

20. 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