When the Sahara was green: what a 7,000-year-old skeleton tells us about lost worlds and future climates.

When I was in Middle School over three decades ago in suburban Barcelona (then called EGB), our primary teacher, known as the “tutor” teacher, gave us some work for the summer vacation before school ended for the year. It consisted of writing a fiction story following the essential narrative elements. She explained that we would need to deliver at the beginning of next year, and it was binding.

It must have been one of the main classes, in which we were clustered with kids from other classrooms based on performance. The school had implemented an experimental method to group kids by learning speed and interests instead of age or any other administrative consideration. These were called “flexible groups,” which I see now as something similar to the honors or AP systems in the US, offering more rigorous or advanced courses to kids showing the desired competence.

I remember being clustered in that particular class along with the more bookish kids, so we must have complied with the assignment for its sake. I remember the assignment because the teacher returned it to me with a sign of suspicion and disapproval, suggesting that I might have copied it from a story written somewhere.

I recall boiling with rage at the teacher’s hint—the feeling of injustice must have been so profound that I can clearly picture the little bunch of white sheets carefully stapled together with the handwritten story on them. The story included a drawn cover page with the characters of the story and my name on it, as well as several technical drawings and illustrations (colored with markers) along with the text.

A Mediterranean pedal-powered adventure

I’m afraid that the reason I remember this event is because the teacher’s skeptical reaction made an impact on me. As a kid, the message I may have read from that adult in a position of authority is that if I let my imagination fly and put some work into creating a fantasy world to share with others, I could be called out instead of praised. I explained that the story was mine, as were the drawings, but the hint of suspicion had been left out.

The story I wrote depicted a group of kids bored in summer, something plausible in a pre-screen, present world where kids didn’t need to be defined as “free range,” for this was the societal default. Perhaps in a not-too-distant future, parents and grandparents from older cohorts who came of age without personal screens will need to be specific about this point when recalling anecdotes of their childhood: “you know, back then we could get bored and there was no screen to resort to, so we would invent things to play, or simply explain stories.”

In the story I wrote for school, the summer ennui sinks in, making the kids prepare an escape plan: looking at the Mediterranean seashore, they wonder about the Med’s southern shore and its fantasies, so they decide to build a pedal-powered flying machine to cross into Northern Africa, where they lead many adventures. Fighting a technical problem in the desert, they are saved by a Bedouin caravan that brings them to the nearest oasis, where they get help from their doppelganger local group of kids, returning to Barcelona not long after.

The story was, of course, infantile and full of cliches. I had been reading some of The Famous Five stories by Enid Blyton and Claude Voilier, as well as Gerald Durrell’s The Donkey Rustlers, but also plenty of comic books. Movies like The Goonies, Jules Verne adaptations and other B movies might have influenced that writing, too. There was a bit of The Little Prince on it, as well as, perhaps, Peter Pan, Cucamonga, or whatever, for kids are sponges when it comes to cultural media, even in our remote pre-internet world.

Perhaps the teacher saw the plausibility of actual fantasy books in the story I had written, but instead of thinking that I might have been into writing stories that tried to emulate the many I had read, she decided to think that I might have copied it all from somewhere, verbatim. Back then, the mere idea of having generative AI chatbots would have been as ludicrous as the flying pedal-powered vehicle in my own The-Famous-Five-style fantasy world, though I can imagine how that same teacher, who may be retired today, would be puzzled in today’s world, trying to police the inevitable.

A lost Eden in the Sahara

My story included a trip through a canyon outside the oasis that opened towards a corridor of lakes and green pastures, an Eden with all sorts of animals and plants, contradicting the torrid reality of the planet’s most immense and inhospitable desert (in the style of Journey to the Center of the Earth).

I must have come up with the idea of setting it up in the Sahara during one of our weekend visits to the nearby beach of Gavà outside Barcelona, where we set up camp for the day under the shade of the pine trees, not far from the water. What would it take to fly to the other shore, where the sand from the beaches would go on into the desert (or, at least, that’s what I must have thought then, watching the Paris-Dakar Rally on TV)?

I probably hadn’t heard back then, not even from TV, about the Gossamer Albatross, a human-powered aircraft designed by Paul MacCready and piloted by Bryan Allen. The design was clever, with the pilot pedaling the aircraft’s sole propeller, which allowed Allen to cross the 22.25 miles (35.6 km) of the English Channel in 2 hours and 49 minutes. In retrospect, my drawings were more fantastic but featured a somewhat similar aircraft occupied by several kids pedaling in a row to power two propellers, one on each wing, enough to cross the Strait of Gibraltar into the African continent.

The idea of finding an Eden in the middle of the Sahara sounded fascinating. Back then, I was really fascinated by worlds that had vanished in the remote past after watching a documentary of sorts about the topic on one of the only three channels available. Myths like the Great Flood from Gilgamesh and the Old Testament, or Plato’s Atlantis, must have been related to regional cataclysmic events, like earthquakes, tsunamis, and enormous floods. We may have explained such events as stories in order to keep a memory of them.

When the Sahara was green and humid

Going back in time a few thousand years to the era between 10,000 and 7,000 years ago during the last Ice Age, the British Isles and the North Sea area from Denmark to France had been one gigantic landmass of pastures and marshes where Stone Age tribes fished and hunted big game. Right around the same time, the African continent was undergoing a humid period; Africa’s entire northern half was much wetter than it is today.

During the late Pleistocene and Holocene geologic periods, much of today’s Sahara desert was a vast world of plenty, not much different from Doggerland in Europe: a never-ending landscape of green rolling hills thanks to a strengthened African monsoon feeding lakes of all sizes around the gigantic Lake Chad (much bigger than it is today) at its core, amid rich grasses and patches of towering trees.

It had not been like that during the preceding Last Glacial Maximum between 26,000 and 20,000 years ago when the Sahara contained dunes and was almost deserted as it is today. The humid period after the glacial maximum, which began over 14,000 years ago and ended 6,000 years ago, was caused by changes in the Earth’s axial tilt, reminding us that apparently isolated events in our planet can trigger massive transformations: a little tilt caused a southward shift of the Mediterranean winter precipitation system. In his book The Earth Transformed, British historian and writer Peter Frankopan explains the consequences of these precipitations over thousands of years:

“In North Africa, the Sahara and the Nile Valley, settled communities also became more common as a result of more plentiful resources — in this case, fish life in particular, which was abundant in the vast chains of lakes and river networks that once crisscrossed the heart of the continent.”

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The fish and game abundance of the Green Sahara encouraged innovations such as pottery around 8000 BC, as findings from Niger and the Dogon plateau in Niger attest, which improved the transportation and storage of food.

Nonetheless, such advances didn’t encourage permanent settlements like the ones from the Neolithic right away in the region: the land had so many resources that it sustained a roaming population that completed their diet with the herding of goats, sheep, and cattle, which preceded crop farming in most parts of Africa.

A kid’s imagination and reality

To local humans inhabiting the area during the Green Sahara period, it must have felt like the imaginary Eden I wrote about for my Middle School assignment, only it happened for real.

In my story, I imagined them as nomadic pastoralists not unlike the Tuareg people, a mysterious and isolated world like the one from Jules Verne’s Journey to the Center of the Earth, whose film adaptations often appeared on TV (there was even a 1978 Spanish production by Juan Piquer Simón, starring English actor Kenneth More and Pep Munné).

Many children are drawn to the concept of a lost world where people and fantastic animals live isolated from the rest of the world, and I wasn’t an exception: the mysterious, Mount-Roraima-like isolated mountain from Close Encounters of the Third Kind must have stimulated my imagination, and I remember well how much I liked the movie when I watched it on TV in the late eighties.

Around the same time, I got hooked on a French-Belgian comic strip of several albums called Les Petits Hommes in the original (The Little Men), a lilliput-like community of people living on the marginal side of the contemporary world: their lives were similar to those of the conventional world though in miniature, happening behind the walls and crawl spaces of people, for they were only a few inches tall.

I found Les Petits Hommes in the magazine Spirou, a Belgian comics magazine translated for the Spanish market. I got really disappointed when I couldn’t get any more Spirous, which I didn’t buy but interchanged with other kids through my older brother.

A lost ancestral lineage in the Green Sahara

All these references and fantasies came tumbling down in the fiction story I wrote that summer in Middle School, an adventure leading the characters to a lost, surprisingly lush world in the middle of the Sahara, reached by the kids of the story by pedaling atop their human-powered aircraft.

It all came to my mind recently as I read about the ancient remains buried at Takarkori, an isolated Libyan cave. The complete DNA retrieved from the best preserved remains among 15 women and children belongs to 7,000-year-old members of a “ghost” branch of humanity that settled in the Sahara and remained there through the region’s humid period without much contact with other peoples migrating in and out of the African continent.

Thanks to the preservation conditions within the cave, scientists could analyze the DNA of two naturally mummified individuals. This allowed a team at the Max Planck Institute of Evolutionary Anthropology in Leipzig, Germany, to recover the two individuals’ whole genomes (and not only the limited mitochondrial DNA, which traces the maternal line and had already been recovered at the site in 2019).

They found that these people belonged to a previously unknown human lineage. According to Johannes Krause, senior author of the study:

“At the time when they were alive, these people were almost like living fossils – like something that shouldn’t be there. If you’d told me these genomes were 40,000 years old, I would have believed it.”

The study reveals that the individuals belonged to a previously unknown ancestral North African lineage. This population isolated in a favorable habitat full of lakes, pastures, game, and resources that didn’t serve as a migration corridor, with far less genetic mixing with people from the north like Neanderthals (according to the study, “Takarkori shows ten times less Neanderthal ancestry than Levantine farmers, yet significantly more than contemporary sub-Saharan genomes”).

Echoes of a Lost World

They lived off fish and herded sheep and goats and might have interchanged cultural knowledge with surrounding people, though this process carried marginal genetic borrowing. Savino di Lernia, coauthor of a study published on the findings in the journal Nature, confirms this hypothesis:

“We know now that they were isolated in terms of genetics, but not in cultural terms. There’s a lot of networks that we know from several parts of the continent because we have pottery coming from sub-Saharan Africa. We have pottery coming from the Nile Valley and the like. They had this kind of lineage, which is quite ancestral, (which) points to some kind of Pleistocene legacy, which needs to be explored.”

Many mysteries puzzle scientists. The group didn’t seem impervious to innovation, as their adoption of herding techniques and the use of pottery to preserve fish and other food, though the cultural interactions with groups that already raised domesticated animals didn’t come with no important genetic interchange or evidence of degenerative inbreeding.

Also, the small community that used the Libyan rock shelter may have reached the region with humankind’s big migration out of sub-Saharan Africa. Their isolation suggests that they were able to survive right before the Sahara became a verdant savanna with trees, permanent lakes, and rivers supporting large animals. Interestingly, though, the ancestors of the newly discovered lost lineage had arrived in an arid land much like today’s Sahara and experienced the region’s transformation during its late Pleistocene and Holocene humid transformation.

As ideas such as de-extinction and geoengineering move from the margins of science into the mainstream, few initiatives are as ambitious as the green wall, for the Sahara and the Sahel, or the attempt to stop the expansion of desertification in Africa by holding back the southwards expansion of the Sahara desert, by planting a 9-mile-wide (15 km) and 4,831-mile-long (7,775 km) band of trees stretching across the Sahel from the horn of Africa to the East to Dakar, Senegal, in Africa’s Atlantic coast.

A tree barrier to stop desertification

Now, restoring 250 million acres (100 million hectares) of degraded land already in the process of desertification may seem a far-fetched, quixotic enterprise. But by looking at things through a long-term-view lens, which Stewart Brand and others have argued fosters a civilization-scale perspective and responsibility, a Green-er Sahara can make as much sense as other contemporary goals.

Any project involving massive afforestation would increase albedo (light absorption), hence boosting evapotranspiration and cooling down temperatures at ground level, which could lead to a shift in atmospheric circulation patterns, ultimately bringing rainfall. It wouldn’t be the first time that the Sahara attracts cyclical wet monsoons.

That said, the green Sahara of the Holocene wasn’t caused by human activity but by a slight orbital shift of our planet, and when those orbital conditions shifted back, the rains retreated back to the north, causing desertification again.

Any attempt to “green” the Sahara nowadays would require constant human intervention as it would go against the current climatic patterns; these people wouldn’t live like the lost tribes that inhabited the region during the African Humid Period between 14,500 and 5,000 years ago, as suggested by the Takarkori rock shelter remains. Still, the idea captured my imagination as a kid and still inspires many people.

The long shade of the Tuareg

If we aim at pragmatic and adaptive ways of looking into the future, the combination of systems thinking, ecology, and engineering could lead to the recovery of long-gone landscapes that might have inspired ancient legends.

The population most associated with ancient pastoralism in the Sahara region, the Tuaregs, did not yet exist as a distinct ethnic group during the African Humid Period, but their ancestors likely lived in the region. As of the latest available research, there’s no confirmed genetic link between the ancient human lineage of the Takarkori Cave and modern Tuareg populations, though the study published in Nature provides intriguing clues that suggest possible cultural and ancestral continuity.

The Berber-speaking Tuaregs are nomadic people spread across the Sahara core and have Berber ancestry with sub-Saharan African and Eurasian back-migration admixture. The pastoralism of the Takarkori people, which involved seasonal migration, survives in the ancestral transhumant lifestyles of modern Tuaregs.

And now, as the wind buries and reveals the stories of millennia beneath Sahara’s shifting dunes, the Tuaregs ride the edges of time — descendants of sand, salt, and stars. Perhaps they are also descendants of old tales of lakes abundant in fish and pasture lands filled with big animals and a mysterious tribe.

In their nomadic resilience, their deep maps of sky and stone, lies a vision for the Sahara’s future: not abandoned, but reimagined.

In the Tuareg, the desert remembers how to live.