Geographical Reasons

The Mayan empire was as populated as Los Angeles today (up to 2,000 people per square mile). As you can imagine, that can cause more problems than just food-shortages. Tom Sever, NASA's only archeologist, pieced together what he believes is the main cause of the collapse. By researching the lake sediment, scientists have discovered that around 1,200 years ago (just before the collapse), tree pollen disappeared almost completely and was replaced by weed pollen. That proves that the trees had been almost wiped out. This can cause huge problems down the road, like erosion and even temperature increase. According to Bob Oglesby, the changing of groundcover would have boosted the region by as much as 6 degrees. This could effect rainfall, which (during dryseasons) could have been deadly for the Mayans. Bones found have indicated malnutrition.

"Archeologists used to argue about whether the downfall of the Maya was due to drought or warfare or disease, or a number of other possibilities such as political instability," Sever says. "Now we think that all these things played a role, but that they were only symptoms. The root cause was a chronic food and water shortage, due to some combination of natural drought and deforestation by humans." (http://science.nasa.gov/headlines/y2004/15nov_maya.htm)

Today, half of the original rainforest has been removed by using the "slash and burn" method. Farmers cut down trees then burn it so they can use the soil from the ashes. Unfortunately, within 3-5 years, the soil becomes exhausted and the farmer must relocate. By 2020, it's estimated that only 2-6% of the rainforest will remain. All I can say is that hopefully, they realize what they are doing before it is too late. We wouldn't want history to repeat itself.