The Sahara Desert used to be home to a thriving ecosystem. About 8,000 years ago, the region had wetter conditions that supported plants, animals, and the people who lived there.
Northern Africa was wetter than it is today during the African Humid Period, colloquially known as the Green Sahara, because of a series of monsoons. As the Earth’s orbit slowly changed, however, rains became less and the vegetation started to die off.
About 5,500 years ago, the Sahara underwent a terminal decline that led to it becoming the desert that we know today.
Some experts think that humans played a major role in the desertification of the Sahara. The practice of early cattle farming called “pastoralism,” in particular, attributed for the loss of vegetation and the region’s shift to an arid land.
Pastoralism is similar to nomadic movement in that it involves moving herds in search of water and fresh pasture.
Findings of a new study, however, suggest that humans did not accelerate the decline of the African Humid Period. They may have actually managed to hold back the onset of the desert by around 500 years.
Chris Brierley, from University College London, and colleagues used a climate-vegetation model to investigate if the end of the African Humid Period occurred earlier than expected. They found that the Green Sahara should have collapsed earlier than it did.
“The model indicates that the system was most susceptible to collapse between 7 and 6 ka; at least 500 years before the observed collapse,” the researchers wrote in their study, which was published in Nature Communications.
Researchers believed that early pastoralists developed ways to efficiently manage the sparse vegetation, as well as the dry and low fertility soils. They also said that the techniques employed by these nomadic cattle farmers helped them adapt to regional changes in the environment.
Brierley and colleagues likewise found that pastoralism may have slowed the deterioration caused by the orbitally-driven changes in climate. They said that their findings support the view that modern pastoralism is not just sustainable. It is also beneficial for the management of dryland environments all over the globe.
“Those places where pastoralists last longer are where there are more resources. It’s a good adaptation to the climate change taking place at the time,” Brierley said in a statement published by the UCL.
“There is now work today looking at what we can learn from nomadic pastoralists, such as selective grazing strategies, which can be applied to sustainable adaptation to desertification that we expect from future climate change.”