It may be a difficult thing to image for some, however the region of Sahara which is presently governed by a barren landscape of sand dunes was just a few thousand years ago a lush green grassland swarming with lakes.
An archaeologist now suggests that humans played a key role in summoning the rapid changes in the natural ecosystem resulting in less rainfall, providing us with pivotal insights into how to cope up with large-scale climate change in the time to come.
Beneath the desert terrain of the Saharas sands are marks of ancient rivers and remnants of plants and animals, an ode to the regions greener past.
A 10,000-year span of what is now known as the African Humid Period is majorly thought to have been caused by an onset of monsoons that had the continent awashed; it is speculated that such wet periods dating back 9 million years ended with changes in Earths orbit.
However, current dictating beliefs blame a 20,000-year-old shift in our planets orbital axis for ending the last big wet, says David Wright from Seoul National University.
"In East Asia there are long established theories of how Neolithic populations changed the landscape so profoundly that monsoons stopped penetrating so far inland," he says.
The Sahara presently is the worlds largest desert, comprised of 10 African countries with a land mass stretching over 3.5 million square miles. Meanwhile most of the desert now receives less than 0.79 inch of rainfall each year. Going back about 11,000 years, the weather was starkly different.
"It was 10 times as wet as today," says Jessica Tierney of the University of Arizona, a paleoclimatologist who measured the rainfall over the last of the 'Green Sahara' periods.
That period happens to overlap with a human migration into the area, bringing farming with them but then 8,000 years ago, over the course of just 1,000 years, the monsoons started to deteriorate.
"It looks like this 1,000-year dry period caused people to leave. What is interesting is the people who came back after the dry period were different - most raised cattle. That dry period separates two different cultures. Our record provides a climate context for this change in occupation and lifestyle in the western Sahara, says Tierney.
It was the impact of the crop-growers who ultimately tipped the climate from damp to dry, according to Wright.
The story that came out of the hypothesis and the resultant study, suggested that communities of people spread leading to them altering the landscape to better accommodate crops and cattle, causing an exchange in plant genus present there exposing the soil to the sun.
Now, as the sunlight bounced from the brighter soil it resulted in the warming of the air building a sort of a feedback loop that affected the atmospheric conditions rightly enough to decrease the frequent monsoon rains benefiting the scrub vegetation over grasslands until rainfall virtually disappeared leaving behind robust desert plants.
It's an interesting idea - and one that isn't necessarily mutually exclusive with the 'wobble' hypothesis, which Wright suggests had a small impact about 8,200 years ago but wasn't permanent.
It sure is an intriguing notion, and one when at that which isnt mutually exclusive with the magnetic-pole-shift hypothesis, however Wright is going to have to build a stronger case to convince the rest of the researchers to rewrite the textbooks.
"There were lakes everywhere in the Sahara at this time, and they will have the records of the changing vegetation. We need to drill down into these former lake beds to get the vegetation records, look at the archaeology, and see what people were doing there," he concludes.
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