Friday, October 9, 2009

"Ancient Mayans destroyed themselves by deforesting their landscape"


     In a new research, NASA funded scientists have determined that the ancient Mayans were themselves responsible for the demise of their civilization, by deforesting and destroying their landscape in efforts to eke out a living in hard times.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.
       Even in rural areas, the Maya numbered 200 to 400 people per square mile.But suddenly, all was quiet.The profound silence testified to one of the greatest demographic disasters in human prehistory - the demise of the once vibrant Maya society.As to what may have happened, some NASA-funded researchers think they have a pretty good idea.
"They did it to themselves," said veteran archeologist Tom Sever.
"The Maya are often depicted as people who lived in complete harmony with their environment," said 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," he added.A major drought occurred about the time the Maya began to disappear.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," explained 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," said 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," he added."The Maya stripped large areas of their landscape bare by over-farming," said Griffin."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," he added.

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