Maya Mystery Solution May be Warning

Images from space are providing scientists with new clues about the mysterious collapse of the Mayan civilization of Central America and some hints about the fates of other ancient civilizations that tried, and failed, to manipulate their environments with massive public works projects. Analyses of satellite images by NASA's Marshall Space Flight Center and others suggest that, at least in the Petйn region of northern Guatemala, the Maya made major ecological mistakes. Those, in turn, led to the collapse of what, around 800 A.D., was one of the most densely populated regions of the New World. "By about 900 A.D., these people had all but disappeared, and we think we're beginning to understand why," NASA archaeologist Tom Sever told the World Archaeological Congress in Washington.

Aerial surveys of the region were performed by Charles Lindbergh more than 70 years ago, but new space-based sensors are enabling scientists to see through the dense jungle growth. "We have been able to see things that have never been mapped before," Sever said. "Some of these features are so subtle that even if you chopped away all the vegetation, you couldn't see them."

A mirror of modern worries

From hundreds of newly discovered cities and towns, fields, roadways, canals and man-made reservoirs, researchers are beginning to see the rise and fall of Maya civilization in a new light -- one that strikes a familiar chord in a modern world that worries about water wars, drought and overpopulation.

The Maya civilization originated in the Yucatan and eventually occupied much of what today is southern Mexico, Guatemala, western Honduras, El Salvador and northern Belize. The Maya initially prospered because the region was dotted with small lakes and ponds. As the population grew, however, the Maya rapidly deforested steep slopes to make way for crops. The resulting erosion clogged streams and rivers with silt and turned the lakes into seasonal swamps.

To supply the water that once had been stored naturally, the Maya built hundreds of man-made reservoirs. For a while, engineering seemed to be the answer. But with a population density equivalent to that of China and every arable acre under cultivation, there was no cushion for bad years. Sometime between 800 and 900, a series of severe droughts devastated the region. The reservoirs dried up and the crops failed. "Within 100 years, 95 percent of the population was gone," Sever said.

The analysis isn't as advanced, but researchers say space-based and aerial images are beginning to suggest that a similar fate may have befallen the Khmer empire, which ruled much of Cambodia between the ninth and 15th centuries.

Similar hints in Cambodia

Rediscovered by French missionaries in the mid-1800s, the Angkor region's archaeological sites have been celebrated primarily for their lavishly decorated temples and stone sculptures.

In recent years, however, archaeologists have mapped an extensive network of roads, canals and reservoirs. The latest radar images by NASA's Jet Propulsion Laboratory show networks of canals and square-cornered reservoirs -- many too faint to be seen from the ground -- that cover more than 300 square miles.

Archaeologists now estimate that the population of Angkor may have reached 1 million at its peak. They don't yet know why it collapsed, but an eco-disaster like that which befell the Maya is one of the leading possibilities.