The Sahara Desert is the largest desert in the world. Covering over 3.6 million square miles (9.3 million square kilometers), it is more or less equal to the entire United States. However, ten thousand years ago, before this immense track of land became the dry Sahara Desert, it was known as the wet Green Sahara, a lush paradise of human, animal, and plant life.
With so much land, it’d be easy to believe that it was inhabited by just as many people as there are in the US, but it’s actually quite the opposite. The Sahara Desert of today is only inhabited by approximately 2.5 million people, just 0.7% of the US’s current population of 329.5 million inhabitants. To further shed some light on just how small this population is, this means there are approximately 1.44 square miles of land per person across the entire Sahara. In the Green Sahara period there were millions more people living across the region and untold animal diversity.
The Sahara as we know it today is harsh, dry, and utterly inhospitable to many types of life. Sprawling with sand dunes and sand-covered plains, the average high temperature in the summer months is over 104 degrees Fahrenheit (40 degrees Celsius) and has even reached upwards of 117 degrees Fahrenheit (47 degrees Celsius).
Though the present-day Sahara doesn’t sound like a very pleasant environment, it is actually preferred by the over 500 plant species and 250 animal species that call the Sahara home today. Between cacti, arthropods, arachnids, reptiles, mammals, and avians, there’s no shortage of fascinating life to be found in the Sahara of the present.
But by far the most interesting thing about the Sahara Desert is how it became a dry region over several thousands of year, when we know it was once the wet Green Sahara.
Research has clearly shown that the Sahara wasn’t always the dry, sandy landscape it currently is. In fact, the Sahara used to be as green as the Amazon, a verdant oasis filled with thousands of diverse species. For archaeologists and anthropologists, the Green Sahara period is well understood, with more than enough evidence to show that it was once a lush paradise.
So, what happened to the Green Sahara? Where did its people and animals go?
The term Green Sahara, which would have looked just like this, refers to the Sahara region approximately 10,000 years ago, when it was a lush landscape filled with green plants and a plethora of animal species. ( Kushnirov Avraham / Adobe Stock)
About the Green Sahara
As previously mentioned, the term Green Sahara refers to the Sahara region approximately 10,000 years ago, when it was a lush landscape filled with green plants and a plethora of animal species. Not only did it have much more plant life, but it also had a massive “mega lake” that spread over 42,000 square miles (109,000 square kilometers)! This higher water quantity is thought to have significantly contributed to the high amount of vegetation and species diversity in the region at a time that our first civilizations were rising in Mesopotamia.
In addition to this unnamed “ mega lake ,” during the Green Sahara period Lake Chad, then known as the “Megachad,” was more than ten times larger than it is today. These giant lakes were supplied with water via enormous rivers, including the Nile River, Niger River, and countless streams. One huge river in the western Sahara that has since dried up doesn’t even have a name!
With this abundance of water, plants, and animals (including elephants, rhinos, warthogs, crocodiles, buffalo, antelopes, giraffes) humans were able to thrive there for thousands of years. Civilizations were able to flourish because they had all the resources they could possibly need in the Green Sahara, including food, water, and shelter. There was never a shortage of game animals for meat or vegetation for plant-based meals or to feed game animals.
More resources for civilization meant that the population of the Green Sahara 10,000 years ago was significantly higher than its population today. Experts say that the Green Sahara was likely home to several million more people than the 2.5 million that currently inhabit it.
Because of this higher population, relationships between communities began to spark and trade between communities became a part of everyday life. With an abundance of goods and resources such as pottery, tools, weapons, plants, and animals at their disposal, communities across the Green Sahara became part of a highly advanced interconnected civilization.
This rock art from the Cave of Swimmers, which is roughly 10,000 years old, is just one piece of evidence that shows how different today’s Sahara Desert was when it was called the Green Sahara! The Cave of Swimmers is located in the mountainous Gilf Kebir plateau of the Libyan Desert section of the Sahara is located in the New Valley Governorate of southwest Egypt, near the border with Libya. (Roland Unger / CC BY-SA 3.0 )
The Evidence of the Green Sahara We Have So Far
The Green Sahara sounds like a plentiful paradise, but how do we know it even existed if it was so long ago? Simply put, experts have been finding evidence revealing pieces of the Green Sahara’s fascinating existence for several years now. Beyond the finding of artifacts, experts have also analyzed seasonal shifts across Earth over the last several thousand years to see how the landscape and climate of various countries have changed over time.
At the time of the Green Sahara, the earth would have been tilted differently on its axis. When the earth tilts at different angles, it changes how solar radiation is able to penetrate the earth’s atmosphere. This would have caused shifts in atmospheric weather patterns including monsoons, which would have contributed to the high humidity in the Green Sahara at this time. This fluctuation in humidity was so significant in history that it was officially named the African Humid Period.
During the African Humid Period , more energy from the sun was able to permeate the atmosphere, which in turn caused an increase in rainfall. That increase in rainfall then resulted in an increase in lakes, rivers, thriving green plants, and countless animal species.
In addition to studying the climate shifts over time, researchers have also studied artifacts linked to the Green Sahara period. These artifacts include rock paintings, pottery, and even a boat. The Dufana Canoe, one of the oldest boats ever recovered, was found in the middle of the Sahara desert in 1987. This discovery further proves that there was once a significant amount of water within the now-dry Sahara desert.
Modern-day animal species also suggest that the landscape of the Sahara used to be different than it is today. Animals such as elephants, lions, and antelopes have different subspecies in the northern Sahara versus the southern Sahara. This makes sense if you consider the landscape of the Green Sahara.
With so many massive bodies of water, it is likely that animals to the north were unable to encounter the animals to the south. This geographic barrier would have led to reproductive isolation between these groups, ultimately leading to allopatric speciation. We are seeing these results today in these different subspecies around the Sahara.
Finally, the rock art found by experts shows evidence of animal rearing including cattle, sheep, and goats. The theme of dairy farming is distinct within these art pieces. In addition to animal and farming paintings, some paintings illustrate the water, including people diving, fishing, and swimming in water.
These historic findings all further confirm that the Sahara wasn’t always the dry, sandy, desolate landscape it is today. Instead, it was once the Green Sahara, a lush paradise, full of connected peoples and abundant wildlife.
This panoramic present-day view of the Katam aka Baramar lake group of Ounianga kebir lakes at Saharan Chad also stands as evidence of the Green Sahara period when there were many huge lakes and big rivers across the region. ( homocosmicos / Adobe Stock)
The People of the Green Sahara
Though knowledge about the people who inhabited the Green Sahara is scarce, we do have some knowledge about their lives based on what we know about the Green Sahara itself. Those residing in the Green Sahara would have lived near the coast of large lakes or the edge of roaring rivers, close enough to have access to fresh water and the bountiful plants that grew from it. They also would have learned to live from the water, likely engaging in activities such as fishing and diving for plants and other underwater resources.
From the rock paintings, we know these people were also very involved in animal husbandry. As previously mentioned, there is a common theme of dairy farming within the paintings, and there is even evidence of pottery being used to cure milk into cream and yogurt . This dairy curing would have provided Green Sahara inhabitants with additional foods and would have also provided more easily digestible foods for lactose intolerant individuals. The notion that they were able to identify that dairy could cause unwanted symptoms in some individuals shows that they had some level of understanding regarding various medical conditions.
As the Green Sahara began to shift towards its current dry climate, the people, now living in an increasingly drier world, would have stayed near to whatever water remained. Since the landscape continued to change over the years, they would have had to continue moving from less water to more.
As the Sahara dried up, the highly advanced civilization of Ancient Egypt began to rise, using the evolving landscape to their advantage. It is likely that the people of the Green Sahara would have interacted with the ancient Egyptians, and they may have even worked together to share resources and develop new technologies at the time.
Ten thousand years ago, when Mesopotamia was just a baby and the Indus Valley civilization was just getting started, the now-dry Green Sahara region looked like this! ( dashabelozerova / Adobe Stock)
Trouble in Paradise: From Green Sahara To Desert
The evidence is clear that the Sahara was once a bountiful land of flourishing vegetation and diverse wildlife. So, what happened? According to the experts, there are several factors that contributed to the drying up of this once-thriving landscape.
The first factor is the shifting of the earth’s axis. Over the course of 20,000 years or so, the earth’s axis shifts enough to change the overall climate in most parts of the earth. A full cycle of this axis-shifting, therefore, takes approximately 40,000 years. Experts suggest that when the earth’s axis shifted several thousand years ago, it caused a climate change large enough that the Green Sahara dried up. Hotter temperatures and less humidity would have significantly contributed to the steady decline of many plant and animal species in the region throughout that time.
The second factor is how human impact has changed the natural ability of this landscape to evolve over time. Evidence of human migration across the Sahara reveals that there is a correlation between community movement and a decrease in plant life over time. However, it is not certain which caused the other. Did plants die because humans used them as they migrated, or did humans migrate because the plants died in the first place?
One theory supporting the former is that the people of the Green Sahara may have allowed their goats to over graze the region which caused the plants to die. This would have also led to erosion of the Sahara’s topsoil, which would have prevented future plants from growing. They could have also begun to use the Green Sahara’s resources faster than it could replenish itself in addition to the already-changing climate due to the earth’s axis.
This would explain how the Sahara dried up even more quickly after the most recent African Humid Period compared to any previous climate shifts before humans. Climatologists say that without human impact, the transition from the Green Sahara to the now-dry Sahara would have been a much slower process.
One day the dry Sahara may become the Green Sahara again but with so many humans living in or around this region the odds say it will be different from the paradise of thousands of years ago. ( Riccardo Niels Mayer / Adobe Stock)
Could Green Be In the Sahara’s Future?
Because we know the earth’s axis changes every several thousand years, experts assume that the Sahara may have gone through several patterns of humid and dry climates. That would mean that this dry spell may not have been the first time the Sahara was more like a desert than a water-rich paradise of diversity and prosperity. It would also suggest that as the earth’s axis tilts again, the Sahara could go back to being green once more with an increase in rainfall.
This time, however, the Sahara also has human impact to combat. With billions more people on Earth compared to the Green Sahara days, climate change has accelerated at a startling rate. Humanity’s rapid harvesting of natural resources continues to destroy natural habitats across the globe, leaving areas such as the Sahara further unable to replenish themselves even if the earth’s axis returned the region to a more humid climate.
The long-term effects of industrial production and urbanization would have to be significantly reduced for the earth to recover its natural ability to heal over time. By reducing our carbon footprint, we can improve the conditions under which these various habitats attempt to replenish themselves.
Between waiting for the earth’s axis to shift and combating human impact, the odds are stacked against the return of the Green Sahara. With scientific advancements, however, we can further study exactly what the Sahara would need to give it the best possible chance of turning green again.
It is possible that with human technological advancement we could develop a system to maintain the Sahara more effectively than our ancestors? Only by taking responsibility to improve our planet for future generations can the Sahara have a true chance of becoming a green, thriving paradise once more.
Top image: As the Earth’s axis tilted towards the Sun, the Green Sahara transitioned to the dry Sahara and still many millions continued to impact this changing ecosystem. Source: appledesign / Adobe Stock
By Lex Leigh