The Sahara is a massive desert that is situated in the northern region of Africa. It covers a significant portion of the African continent and shapes the geography of several African nations. It is the largest non-polar desert in the world. The desert is thought to be about 2-3 million years old, with some estimates as high as 7 million years old. Interestingly, the history of the desert shows that it has not always been a desert with the region having alternating periods of wetness and dryness.
Geography of the Sahara Desert
With an area of about 3.6 million square miles, the Sahara Desert is the world’s third largest desert after the Arctic and Antarctica. To put the size of the desert into perspective, the desert is as big as the United States or China. The area of the Sahara is about 31% of Africa’s total area. The desert covers large parts of a number of countries such as Sudan, Tunisia, Egypt, Mali, Libya, and Chad.
The desert has a length of about 3,000 miles and a width of about 1,100 miles. The Sahara spans from the Red Sea and the Mediterranean Sea in the north all the way to the Atlantic Ocean in the western side. At the region where the desert comes together with the Atlantic, the landscape changes gradually from a desert to a coastal one. The southern side of the Sahara is bordered by the Sahel region. The Sahara is subdivided into smaller deserts including the Tanezrouft Desert, the Nubian Desert, and the Sinai Desert among others.
The desert is known for its hot temperatures and arid conditions. The highest recorded temperature in the Sahara is 116.6 °F with average temperatures during the hottest months reaching 100.4 to 104.0 °F. However, variations in elevation, temperature, rainfall, and soil divide the Sahara Desert into several distinct ecoregions with each comprising of unique plants and animals. Some of the animals of the Sahara include the deathstalker scorpion, red-necked ostrich, desert foxes, and the addax antelope.
Formation of the Sahara Desert
Before the formation of the Sahara Desert, the northern part of Africa used to have a moist and semi-arid climate. The exact age of the desert is unknown although most experts argue that it was formed between two and three million years ago. Some experts claim to have evidence that supports the theory that the desert has been in existence for at least seven million years although nothing has been substantiated. Examples of such evidence include the prehistoric dune deposits that are located in Chad.
However, recent studies from the Bjerknes Centre for Climate Research in Norway came up with new theories after using advanced analytic models. The new theory was formulated after new simulations were made taking into account things like atmospheric chemistry, the orbital position of the earth, and other factors. The study showed that the Sahara experienced at least a 50% drop in precipitation some seven million years ago. The drop in precipitation, as was suggested by the experts, was caused by tectonic action since changes in vegetation cover alone could not explain the decline.
The theory states that the formation of the Sahara began about 250 million years ago. At that time, the Tethys Sea, which was a huge water body, acted as the separator between the supercontinents of Laurasia and Gondwana. As the two supercontinents came apart, the Eurasian plate ended up colliding with the African plate. The collision is what led to the formation of the Himalayas and the Alps. As the plates continued moving away from one another, the Tethys Sea kept on shrinking until it eventually disappeared into the Mediterranean Sea.
Between seven and eleven years ago, the formation of the desert began in earnest. The western region of the Tethys Sea, which was responsible for most of the moisture in North Africa, began closing up. In its place, the Arabian Peninsula slowly started forming. Eventually, all the water in that section of the sea was replaced with land and thus the desert was formed. Naturally, any plant, animal, and even ancient human life would have been severely affected by the reduction in moisture. An example of a human ancestor affected was Sahelanthropus tchadensis, who lived in the southern region of the Sahara in the region that is present-day Chad. Some of the animal remains found in the desert from that period include dinosaur fossils (such as Ouranosaurus and Jobaria), and crocodiles.
Based on historical evidence, experts in the field are almost sure that the desert will be full of vegetation again in the future. The reason for this expectation can be explained by the Sahara pump theory, which explains the cycle that the desert goes through. According to the theory, the desert experiences alternating periods of wetness and dryness every 41,000 years. After this period, the earth’s tilt usually changes. Regardless of the change, the tilt is usually between 22° and 24.5°. Currently, the desert is experiencing a season of dryness. However, according to the theory, the desert will experience wet conditions after 15,000 years or so. In 15,000 years, the North African monsoon winds should be strong, which would bring about an increase in the region’s precipitation.
One of the oldest civilizations to have lived in the desert was the Kiffian civilization. Kiffians lived in the desert some 10,000 years ago during a period when the desert was going through a wet phase. Considered a Stone Age civilization, Kiffian remains were found in 2000 at a place called Gobero, which is in Niger. Evidence shows that the people hunted and fished, which suggested that the land was rich enough to provide. When the desert experienced a dry phase, these people vanished. After the Kiffians, other cultures and people lived in the desert such as Tenerians and Nubians.
One of the greatest civilizations to have ever lived there is the Egyptian civilization, which is considered one of the greatest civilizations during its time. Unlike the older civilizations, Egyptians were much more advanced in their daily activities. They had a social structure and permanent settlements. In addition, they utilized the land for a number of things such as crop and animal farming, fishing and hunting, and other activities. Eventually, the desert became dry again and most of the civilization ended although evidence of its existence survives to this day.
In urban periods, one of the earliest civilizations was the Garamantes, which started about 500 BCE. In order to survive in the desert, the people came up with tunnel systems for channeling water into Wadi al-Ajal, which is the heart of the desert. As the civilization grew and expanded into other territories, they acquired new ways of doing things as well as more slaves to work in the tunnels. The civilization even mingled with ancient Greeks and Romans and engaged in trade with one another. Unfortunately, these people died out after exhausting all the water in the aquifers.