10,000 years ago, today’s largest hot desert Sahara was not just a gray land rather it was very much green with different trees, lakes and animals. Then what happened to the old Sahara? Study said humanity may be the reason for the transformation of green Sahara into a trackless dessert.
There was a time between 11,000 and 4,000 years ago when more rain fell across the northern two-thirds of Africa. In fact, the vegetation of the Sahara was largely diverse and had different species found on the margins of today’s rainforests along with desert-adapted plants.
Many modern research studies revealed natural changes in vegetation or alterations in the Earth’s orbit was the possible reason for changing the ecology and climate.
But the archaeologist of Seoul National University, Dr. David White wanted to challenge the beliefs. In his new paper, he wrote human actions were the reasons for climatic and ecological changes occurring in North America, New Zealand and Europe.
The archaeologists also pointed out the theories of Neolithic populations in East Asia which changing the landscape enough to redirect the course of monsoons.
Dr. David based his analysis on existing archaeological evidence which elaborated pastoral human populations first appeared across Sahara. He then compared this with records of how scrub vegetation spread across the same region to act as an indicator of the desertification process.
According to his research, around 8,000 years ago, pastoral communities emerged and spread westward from the regions surrounding the river Nile. His study showed scrub vegetation also increased in these regions at the same time humans began spreading west.
The archaeologist said the pastoral communities and their dependence on agriculture had a major impact on the ecology of the region. He maintained as the livestock required large areas the vegetation was cleared and for that, the amount of sunlight reaching and reflecting off the surface of the earth would have increased.
The increased albedo may have had an impact on the atmospheric conditions which reduced the amount of monsoon rainfall the region received. For the lack of rain, the vegetation began to destroy and it was a start of desertification. It was spreading faster until the entire Sahara came to its modern state.
Mr. David indicated 10,000 years ago Sahara was dotted by lakes which would have protected the records of the vegetation in the region and how it changed over time.
He stated modelling the effect of vegetation on climate systems is difficult and data gathering efforts are critical in developing more sophisticated models.
His findings are important at this time when the humankind facing the biggest challenge of climate change. Historical ecology teaches us when an ecological threshold is crossed, destruction begins. We must keep a balance between economical development and environmental system.