TOP TEN -
http://news.nationalgeographic.com/news/2008/12/081219-top-ten-archaeology.html#3

Maya May Have Caused Civilization-Ending Climate Change
Researchers from the Marshall Space Flight Center in Huntsville, Alabama, launched the satellite program, known as SERVIR, in early 2005 to help combat wildfires, improve land use, and assist with natural disaster responses.
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More than a hundred reasons have been proposed for the downfall of the Maya, among them hurricanes, overpopulation, disease, warfare, and peasant revolt. (Read "Maya Rise and Fall" in National Geographic magazine (August 2007).
But Sever, NASA's only archaeologist, adds to evidence for another explanation.
"Our recent research shows that another factor may have been climate change," he said during a meeting of the American Association of the Advancement of Science in Boston, Massachusetts, earlier this month.
One conventional theory has it that the Maya relied on slash-and-burn agriculture. But Sever and his colleagues say such methods couldn't have sustained a population that reached 60,000 at its peak.
The researchers think the Maya also exploited seasonal wetlands called bajos, which make up more than 40 percent of the Petén landscape that the ancient empire called home...cont'd
http://news.nationalgeographic.com/news/2008/02/080229-servir-maya.html