The stark contrast between South and North Africa will never escape your attention when you look at the map of Africa. In the South, there is lush greenery while the Sahara desert covers a vast stretch of North Africa and is the biggest in the world. The expansive sand dunes, the relentless sun, and the hidden oases cover eleven countries in the Sahara – Sudan and Egypt to the East (refer to the Sahara desert Egypt map), Morocco, Western Sahara, and Mauritania to the west, Algeria, Tunisia and Libya to the North and Mali, Niger and Chad to the South. Many thousands of years ago before the Sahara desert discovery, the entire African subcontinent was covered in lush green vegetation and there was no sign of the desert we see today. Here begins the story of the Sahara desert discovery that is currently making waves as Sahara YouTube.
The Sahara Desert Discovery
Those interested to know what percentage of desert covers Africa might feel surprised that it covers 31% of Africa.
The desert land of the Northern region was like any other tropical region covered with grasslands, rivers, lakes, and even forests. Therefore, how did the massive transformation happen and all water vanished without any trace of green? Archaeologists and paleoecologists have been tirelessly looking for the answer for years and could not progress much. However, the idea of archaeologist David Wright published in the journal Frontiers in Earth Science appeared to have made some breakthrough. Wright pointed at humans as the possible cause for transforming the once-green regions into a desert.
The incredible transformation resulted in the creation of the Sahara desert. To understand the Sahara desert meaning we must look at the Arabic word Sahra which means desert. Altogether deserts cover about 9 million square kilometers which are equivalent to 18 times the size of Spain. Before we delve deeper into the human role in the geographical transformation of the African continent, we must understand the climatic factors that existed.
The Climatic Condition of the Sahara
Bouts of humidity and aridity have been typical of the climate of the Sahara region. Whenever the earth experiences slight wobbles that affect the tilt of the Earth’s orbital axis it causes fluctuations and even changes the angle of solar penetration into the Earth’s atmosphere. Throughout the Earth’s history, at repeated intervals, during the West African monsoon season, heavy energy poured in from the sun. The spells of high energy, known as the African Humid Periods brought much more rain over North Africa.
More rain made the Sahara desert countries as green as we see in the tropical countries with lakes and rivers flowing across the countries. The pattern of the climate persisted until things started changing sometime between 8,000 and 4,500 years ago. Some areas changed from humid to dry so rapidly that defied the explanation of the earth’s orbital process. It appears something more contributed to the transformation of the region into the Sahara desert that we know today. Although scientists did not know exactly what could accelerate the transformation they were sure that something was amiss.
Wright Discovered a Pattern in the Formation of the Sahara Desert
As Wright drilled deeper into the environmental and archaeological data of the period, mostly pollen records and sediment cores, he could see an emerging pattern. Wherever the archaeological record confirmed the presence of humans with their domesticated animals or ‘pastoralists’, there was a corresponding change in the variety and types of plants. It appeared that whenever humans along with their flocks of cattle moved towards greener pastures they left behind vast stretches of scrub and desert thus forming the new Sahara.
Humans Contributed to an Accelerated Transition
Wright believes firmly that the data pattern revealed the real picture on the ground and as it happened. Overgrazing was the prime cause of the reduction in atmospheric moisture. Plants give off moisture and help in forming clouds while enhancing albedo, the fraction of light reflected by the earth’s surface. Wright suggests that this could have abruptly triggered the end of the humid period rather than the changes triggered by the orbital process. Moreover, the nomadic population could have used fire as a land management tool which further accelerated the pace of converting green stretches into a desert. You will find these facts mentioned in a recent YouTube Sahara video.
Geologists have a Different View
Geologists believe that desert formation was inevitable due to the way the Earth’s orbit works. They believe that the abrupt transition from green to desert was due to the changes in the amount of dust and regular old vegetation feedback. The periodical weakening of the West African monsoon will slowly degrade the landscape. At some point, the change would gather speed as it went past the tipping point.
As the orbit slowly changed and it rained less, humans might have turned to domestic animals (cattle) for sustenance. Perhaps, the climate pushed people to raise herds of cattle which eventually led to overgrazing and hastened the denudation or destruction of foliage. It paved the way for desert formation as confirmed in a recent YouTube Sahara video.
From Hypothesis to a Theory
Wright’s findings are more of a hypothesis and more research is necessary to match archaeological data sets with the data gathered by geologists. With sufficient correlations, it could be possible to develop a theory to establish the reason for the mismatch in the pace of climate change at the end of African Humid Periods and orbital timescales and the irregularity of AHP across Africa.
However, Wright firmly believes in the human role in ecological changes which can be good in some cases but some may have threatening effects on the Earth’s sustainability. The story of the Sahara desert discovery is an example of the latter.
