Incredible Facts About the Sahara Desert


It’s the largest hot desert in the world. At 3.5 million square miles, it’s over half a million more in size than all of Australia. If you were to combine all the deserts in North America with Asia’s Gobi Desert, you could still fit three of those combined deserts inside the Sahara, and likely be guilty of quite a bit of climate change. It’s a big place, if you catch our (sand) drift. 

It’s also a fascinating tan portion of this little blue ball we call home. It’s changing all the time, and not too long ago it was unrecognizable. It’s also in many ways little to nothing like what you think it is. Those are just some of the surprises this list has in store. 

10. The Elusive Sand

When you first hear the name Sahara, you probably imagine rolling sand dunes. It’s an understandable impulse, considering that Sahara is Arabic for “sand.” Not to mention that there are dunes in the Isaouane-n-Tifernine Sand Sea in Algeria that have been recorded as towering 450 meters in height. Yet it’s still a mostly incorrect image. Sources vary a bit on this, but only between 15% to 25% of the Sahara is covered by sand. 

So what is most of it, actually? It’s quite the mix. Rocky plateaus, salt flats, fields of gravel, mountain ranges, a good number of lakes including Lake Chad though most of them are saltwater lakes. As we’ll see in later entries, even if it’s not the majority of the terrain, the amount of sand that erosion has produced in the Sahara is more than enough to have a major impact on other continents. 

9. The Green Period

If you had been around 20,000 years ago, the Sahara Desert might have been a place you’d want to be instead of a place you’d have nightmares about being stuck in. In 2018, the Massachusetts Institute of Technology released a study of the last 240,000 years of sedimentary deposits in the desert. They found that every 20,000 years or so, the Sahara alternates between a dry environment and a wet one. Indeed, fish fossils indicate that a number of ancient rivers (a.k.a. paleorivers) to rival the Nile have completely dried up. 

One of the more historically significant aspects of this is that relatively new studies such as a study published by the University of Hull in 2013 indicate that these past lush areas would have allowed for human migration. This goes against the old model that the Nile would have been the only route for early humans leaving the African continent. Entire migratory projections were thrown into question as a result, as we learned we might have been less capable of keeping tabs on our ancestors than we expected.   

8. The Human Origin?

Although as mentioned the alternation of the Sahara from desert to more fertile land is pretty cyclical, In 2017 a new postulation emerged. David K. Wright of the Department of Archaeology at Seoul National University published a report that the recent humid period for the Sahara was actually cut short an unnatural 4,500 to 10,000 years ago by human error. His theory is largely based around the corresponding time that humans began domesticating animals and adopting agrarian lifestyles, which through centuries of overuse altered the climate for the region. 

Wright’s postulation has much larger grounding than it might seem. The sort of environmental damage through over-farming that he theorizes is observable through the disastrous American Dust Bowl of the 1930s. In ancient times as well, it is general scientific consensus that nomadic herders in the Central Asian Steppe used clear cutting and brush-burning to such an extreme extent that they had a measurable impact on monsoon seasons roughly 6,000 years ago. Not to mention in 1800s New Zealand as British colonizers consolidated the land. If this assertion of ancient anthropogenic climate change is true, can you imagine trying to convince those ancient farmers and herders that they could be having that sort of impact on the land? 

7. The Growth

While there are many beautiful sights throughout the Sahara as it spans eleven nations, it’s not really something that too many people want to grow. In fact its growth will be interpreted by many as an ominous sign for the future. And yet the Sahara Desert is growing according to a 2018 study by the University of Maryland, supported by the National Science Foundation. This is not a recently started occurrence, for it’s grown approximately 10% in the past century. This is in addition to its usual annual cyclical growth and contraction, which causes its size to change between 11% and 18% a year depending on the season. 

Obviously it’s not as if there are clearly defined natural borders around the edge of the Sahara. It’s more that the area of North Africa which receives less seasonal rainfall has expanded. Nor has it been a straight increase. In the 1950s there was a notable cooling period. But since the 1980s a drought began which effectively never quite came to an end. The largest amount of expansion is into the savannas of Sudan. Most notably, scientists are positing that much of this expansion is due to a cyclical Atlantic Multidecadal Oscillation rather than being a direct consequence of climate change

6. When It Snows…

Even though trivia junkies might like to trip you up by saying technically Antarctica is the largest desert in the world since it receives so little annual rainfall it qualifies as one, the majority of people still don’t imagine snow when they picture the Sahara. And aside from a handful of times over the decades, they would be entirely correct. 

Take for example the region of Ain Sefra in Algeria. The first recorded snowfall to cover its sand dunes was in 1979. It didn’t snow again until 2016. Then, curiously, it snowed again in 2018. Then once again in January 2021. These were not insubstantial flurries either. In 2016, it was blizzards that dumped a solid meter in some areas. In 2018 it was more than a foot. Unfortunately for fans of winter wonderlands in deserts even the deeper snows don’t really last, as the more than foot of snow in 2018 was completely melted by afternoon on the same day it came down. It was a good visualization of the idea of a snowball’s chance in Hell. 

5. Land of the Abandoned

On a grim note, since Sub-Saharan Africa currently has the largest number of migrants in the World, very large numbers of them are being left to their fate in areas of the Sahara. In 2018 alone there was eyewitness testimony of 1,400 persons perishing as they attempted to cross the desert, which of course only represented a relatively small fraction of the whole. For example that same year 13,000 migrants were expelled from Algeria alone. 

In September 2020, a group of 83 migrants were being smuggled to Libya. Instead, 143 miles from civilization, the smugglers spotted military vehicles. So, they robbed their clients and left them without food or water. It was only by incredible good fortune that the migrants were rescued instead of joining the countless victims of the Sahara, but they still served as a dire example of the fate that could be awaiting desperate people out there in the wastes.  

4. Coming to North America

The distance between North America and the Sahara is 4,862 miles. That might seem like an insurmountable distance for specks of dirt, but nature finds a way. In fact, according to, an estimated 180 million tons of dust blows over the Atlantic Ocean. Of that, a substantial portion manages to reach North America without touching water. As satellite photos indicated, winds in March are particularly severe and good for this form of aerial delivery.  

There was an interesting bonus to this state of affairs in 2020. As reported by Marshall Shepard, director of Atmospheric Sciences at the University of Georgia on NPR, because of an easterly crosswind the United States of America was hit by a Sahara dust cloud that was “off the charts.” As a result while in some areas the sky was less blue than usual, during the sunsets the clouds of dust were unusually vivid colors

3. Vital for South America 

While they were little more than a novelty for North Americans, for South Americans in 2020, Saharan dust is literally a livelihood. Those transcontinental dust clouds bring vital nutrients that are vital to the Amazon Basin being as full of diverse life as it is. The most significant nutrient that they bring is phosphorus, 22,000 tons of which is delivered over 1,600 miles every year among 43 million other tons of dust. All free of charge. It’s a good thing too, since erosion and river flow deprives the basin of roughly that amount every year, so it would be a floral disaster if the Sahara stopped replenishing it.  

The main flow of vital nutrients surprisingly comes not from a west coast nation like Morocco as you would expect. It comes from the 7,000 year dry lake bed Bodélé Depression in northern Chad, which is located in the Southeastern Sahara. It makes more sense when you consider that this 500 mile area generates roughly half the dust of the entire Sahara, and that the phosphorus comes from the long dead microscopic life forms from back when it was potentially the largest lake in the world. Never has one continent owed so much to a lake on another continent. 

However, all these nutrients come with a cost.   

2. Deadly Dust

As much as all that Sahara dust can make life possible in some regions, it can also shorten lives in large numbers, directly and indirectly. For example the large deposits of dust in the waters of North America has been found to promote the growth of a toxic form of algae known as Red Tide

Much more harmful is what the dust does to children and infants in Africa itself. In areas which get enough dust to raise the pollution levels ten micrograms per cubic meter above the base level, it raises infant mortality rate between 18-22%. It’s so deadly that in June 2020 Stanford University reported that plans were being drawn up to try introducing significant groundwater to Bodélé Depression, with projections that it would cost roughly $60 per life saved. Even beyond the massive logistics of such an operation, remember that it would deprive South America’s greenery of valuable minerals. Considering the amount of oxygen produced by the Amazon rainforest, the impact of that could be felt around the world.  

1. Vanished Ancient Peoples 

The Sahara didn’t just hide a past of millennia as a green paradise. Entire civilizations have been lost to the very literal sands of time and their remains have only recently been rediscovered. For example it wasn’t until 2011 that the site of a community known as the Garamantes were discovered in Southern Libya. This was no roving band of nomads either. Thousands of years later the remains of fortresses that they built still stand as much as four meters tall. The remains of their communities also feature elaborate subterranean waterways that were estimated to have required 77,000 years of labor. And yet the site is so remote and inhospitable that it took years for studies to be conducted, and they were rated inadequate at the time.  

There are also tantalizing hints of mysterious civilizations leaving behind hundreds of cultural monuments that date back thousands of years in the Western Sahara. They range from relatively simple patterns of stones to relatively complex structures that resemble stone tables called “dolmen.” Unfortunately these have proved even more difficult to study as they are inside territory that as of 2019 was controlled by the terrorist group Al Qaeda. Still, if the history of the Sahara teaches us anything, it’s that no status quo lasts forever, so those answers may come out before we know it. 

Dustin Koski collaborated with Jonathan “Bogleech” Wojcik on Return of the Living, a post-apocalyptic ghost novel.

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