National Geographic : 2009 Oct
of the Sahara were transformed to savanna. Human communities have pulsed here like the explosion of plants a er a rare rain. When moist eras visited, they thrived. When the dry times returned, they shrank or collapsed. How does one locate waterways of long ago? From way up high. Using radar images taken from space, Migrations Project team members Kevin White and Nick Drake have been able to map the location of mineral residues from an- cient lakes and springs, then steer their Land Rovers to those spots, where paleoanthropolo- gists Robert Foley and Marta Mirazón Lahr discovered stone tools, arrowheads, replaces, graves, and other clues to human occupation. e earliest modern humans in the region were hunters and gatherers who lived in a savanna landscape about 130,000 years ago. ose people cleared out when the rains tapered o about 70,000 years ago, but then the rains returned and people moved in again. is back- and-forth migration is called the Saharan pump, a movement of people in and out of northern Africa as the climate shi ed. Scratched on the desert s rocks are the memories of a wetter Sa- hara, when water-dependent creatures such as lions, elephants, and rhinoceroses lived here. A funny thing happened when the most re- cent wet phase ended. About 5,000 years ago the rains stopped once more, the lakes disappeared, and the desert took hold. Yet this time the people stayed. Rock art suggests they had already made the transition from hunting to raising livestock. Next came the rise of a society that would begin building towns and make the transition to agri- culture: the Garamantian civilization. The Garamantes flourished here in a cli- mate much like that of the Sahara today. Many scholars assumed they were desert nomads, but excavations at their capital city, Garama (near modern-day Jarmah), and land surveys by Mattingly s team have shown they were sedentary people living off oasis agriculture. They constructed a sophisticated irrigation system that allowed them to grow wheat, bar- ley, sorghum, date palms, and olives. Under- ground canals---called foggaras---tapped into Traffic accidents are few, but billboards featuring Libyan ruler Muammar Qaddafi are everywhere in Fezzan's major city, Sabha, where less than half an inch of rain falls yearly. Beyond the city and a handful of towns lies the roadless Sahara. Charles Bowden is the author of Killing the Hidden Waters. George Steinmetz made the aerial pictures for this story from his motorized paraglider, which he assembled a er his arrival in Libya.