The Sahara Desert was once lush and populated
At the end of the last Ice Age, the Sahara Desert was just as dry and unattractive as it is today. But sandwiched between two periods of extreme drought, a few millennia of heavy rain and lush vegetation.
During those few thousand years, prehistoric humans left the congested Nile Valley and established settlements around rain basins, verdant valleys, and rivers.
Past climate change and its effects are detailed in the July 21 issue of the journal Science.
When the rains came
Some 12,000 years ago, the only place to live along the Eastern Sahara Desert was the Nile Valley. Being so crowded, prime real estate in the Nile Valley was hard to come by. Land disputes were often settled by hand, as evidenced by the Jebel Sahaba cemetery where many buried people died violently.
But about 10,500 years ago, a sudden gust of monsoon rains over the vast desert turned the region into habitable land.
This opened the door for humans to settle in the region, as evidenced by 500 new radiocarbon dates of human and animal remains from more than 150 excavation sites.
“Climate change in [10,500 years ago] which transformed most of [3.8 million square mile] Great Sahara in a savannah-like environment occurred in just a few hundred years, certainly less than 500 years, âsaid Stefan Kroepelin, study team member at the University of Cologne in Germany.
Frolic in the swimming pools
In the Egyptian Sahara, semi-arid conditions allowed the growth of grasses and shrubs, with some trees growing in valleys and near groundwater sources. Vegetation and small, episodic rain pools prompted animals well adapted to dry conditions, such as giraffes, to enter the area as well.
Humans also frolic in the rain pools, as shown in rock art from southwestern Egypt.
In the Sahara further south of Sudan, lush vegetation, sturdy trees and permanent freshwater lakes have persisted for millennia. There were even large rivers, like the Wadi Howar, once the largest tributary of the Nile from the Sahara.
âThe fauna included very demanding species such as elephants, rhinos, hippos, crocodiles and more than 30 species of fish measuring up to 2 meters (6 feet),â Kroepelin said. LiveScience.
A chronology of the occupation of the Sahara [See Map]:
- 22,000-10,500 years ago: the Sahara was devoid of any human occupation outside the Nile Valley and extended 250 miles further south than it is today.
- 10,500 to 9,000 years ago: the monsoon rains began to sweep over the Sahara, transforming the region into a habitable zone quickly colonized by the inhabitants of the Nile valley.
- 9,000 to 7,300 years ago: Continuous rains, vegetation growth and animal migrations lead to well-established human settlements, including the introduction of domestic animals such as sheep and goats.
- 7,300 to 5,500 years ago: the retreating monsoon rains initiate the desiccation of the Egyptian Sahara, prompting humans to move to the remaining habitable niches of the Sudanese Sahara. The end of the rains and the return of desert conditions throughout the Sahara after 5,500 inhabitants coincided with the return of the population to the Nile valley and the beginning of Pharaonic society.