When the Sahara Was Green: How Our Greatest Desert Came to Be

by Martin Williams

The Sahara is the largest hot desert in the world, equal in size to China or the United States. Yet, this arid expanse was once a verdant, pleasant land, populated by rivers and lakes. The Sahara sustained abundant plant and animal life, such as Nile perch, turtles, crocodiles, and hippos, and attracted prehistoric hunters and herders. What transformed this land of lakes into a sea of sands? When the Sahara Was Green describes the remarkable history of Earth’s greatest desert―including why its climate changed, the impact this had on human populations, and how scientists uncovered the evidence for these extraordinary events.

From the Sahara’s origins as savanna woodland and grassland to its current arid incarnation, Martin Williams takes us on a vivid journey through time. He describes how the desert’s ancient rocks were first fashioned, how dinosaurs roamed freely across the land, and how later, it was covered in tall trees. Williams discusses a plethora of questions: Why was the Sahara previously much wetter, and will it be so again? Did humans contribute to its desertification? What was the impact of extreme climatic episodes―such as prolonged droughts―upon the Sahara’s geology, ecology, and inhabitants? Williams shows how plants, animals, and humans have adapted to the Sahara and what lessons we might learn for living in harmony with the harshest, driest conditions in an ever-changing global environment.

A valuable look at how an iconic region has changed over thousands of years, When the Sahara Was Green reveals the desert’s surprising past to reflect on its present, as well as its possible future.

Genres: Nonfiction, Science, History, Nature, Geology, Geography, Africa

222 pages, Hardcover

First published October 5, 2021

About the author

Librarian Note: There is more than one author in the Goodreads database with this name.

Reviews

[Peter Tillman · Rating 3 out of 5]

A Nature magazine pick:
"On Saharan desert rock, prehistoric artists engraved or painted scenes of cattle camps and herds of giraffes and elephants. Even hippos flourished by lakes. Some 15,000–5,000 years ago, the region was green: the tropics received more solar radiation than they do now, which strengthened the monsoon and brought both summer and winter rains. This vivid historical survey by Earth scientist Martin Williams is the result of a lifetime’s work. Are humans responsible for the region’s current aridity? No, says Williams."

I hadn't realized the desertification there went so fast, and was so recent. 240 pp: short & sweet. As always, read the publisher's introduction first.

It's a decent book with some problems. Most notably, the index maps that show elevations have the medium and higher elevation-areas reversed on the legends! This puzzled me until I figured out what happened, and it's a pity the author or editor didn't catch it. There are various other typos that slipped through, more signs of careless editing. There is a lot of repetition from one section to the next -- just skim when you get to those. Short book, and not much else out there on this topic.

Author's main points:
● The Sahara is a very large desert, extending about 5,000 km east-west and about 3,ooo km north-south. Total area: around 9 million sq km, the size of China or the USA. Largest hot desert on earth.

● It hasn't always been as dry as today. During the Ice Ages, its climate was generally much milder and wetter than today.

● The roots of the Sahara's highly-variable climate go back to around 7 million years ago: the African continent is moving North due to plate tectonics, and the Sahara region has moved into a zone of generally dry, descending air, which is the general root cause of deserts worldwide. While human activities may contribute, the climate is controlled by geophysical forces outside human control (although local politicians can make things worse!).

Overall rating: 3 stars. I wish the author had paid more attention to making his points concisely, and I wish he and his editors had been better proof-readers! Oh, well. I did learn quite a lot about an area that I don't know well.

[Mansoor · Rating 3 out of 5]

تاریخچه‌ی زنده و خوش‌رنگی از صحرای بزرگ آفریقا

[Deb Omnivorous Reader · Rating 3 out of 5]

In this interesting book the author introduces us to the Sahara, which I learn, is the largest hot desert in the world. As I come from Australia and have visited my share of hot and of desert that is pretty impressive. This book combines geography, lots of geology and palaeontology to describe not only the desert today, but the way it used to be. At various times in geological history the Sahara was greener than it is today and Williams shows how we know this and examines the evidence for the previous ecosystems the Sahara has held and the theories of how they came to change.

I really enjoyed the well laid out descriptions of the geological history of the Sahara, and the way that rock paintings, tribal lore and the geo-sciences describe previous Sahara, full of plant and animal life, Nile perch, turtles, crocodiles, giraffes and hippos. I loved the undramatic, almost understated way in which these previous era's of prehistoric hunters and herders are described, the verbal reconstruction of those ancient woodlands, savannas, lakes and rivers.

Williams also address the question of what transformed this land of lakes into a sea of sands: What was responsible for the 'desertification' and I really enjoyed his meticulous descriptions of the theories proposed, as well as the frequent rebuttals of those theories.



In one way however, I think I did both the book and myself a disservice by listening to it as an audiobook. I don't think this is the best way to enjoy this marvellously researched and very nicely written book. For example, one of the things that will make it logical and well constructed to read are the frequent headings. But, when narrated, I usually could not in any way tell that they WERE headings (there seemed to be no inflection, or pause of the narration to telegraph it), so I spent time trying to make this random sentence fit in with the previous sentence, and often lost the thread of the narration that way.

The narrator is a Dr Mike Wells, not credited on the audiobook shown on Goodreads (which is disgraceful) and about whom I know nothing. Seriously, just for fun try googling Dr Mike Wells with nothing else to go by (I am guessing he is NOT the baptist preacher/minister or the pulmonary doctor). He has a very nice soothing voice - but, when listening in a moving car on a long drive that is not necessarily a good thing. I missed a lot in the early chapters because the voice was too soft and because some of the words seemed ...oddly... pronounced. That does not matter for something in your primary field of interest but coming from a science I do not know that much about it was at times disorienting. The only one I remember is diatoms. I don't think there is any accent or intonation on earth that could make me NOT understand that word, but I did pause the recording to think about the pronunciation. Some of the geology terms - I still don't know what they are.

So, great book I DO recommend it! I might go back and re-read it one day, only really read it this time. I think I will get more out of it that way.

[Michael · Rating 3 out of 5]

Very readable book about the Sahara and its ecology, archaeology, and climate over the last seven million years (although mostly focused on the last 20,000 or so). The book wanders into digressions at various points, but overall I would recommend reading this book if you are interested in those topics.

[Dagmar Iber · Rating 3 out of 5]

The book is written by an Australian, Cambridge-educated scientist with decades-long experience in studying the cycles of climate change that shaped the Sahara, and life within. The book provides a vivid introduction to the topic, explains the methods and difficulties in studying the history of the Sahara, and finally argues that humans had a minor impact on its recent desertification. I would have hoped for more details on the latter to better understand the relative contributions and impacts, but at least the book got me interested to now look up the details myself.

[Preetam Chatterjee · Rating 5 out of 5]

Book: When the Sahara Was Green: How Our Greatest Desert Came to Be
Author: Martin Williams
Publisher: ‎ Princeton University Press (5 October 2021)
Language: ‎ English
Hardcover: ‎ 272 pages
Item Weight: ‎ 590 g
Dimensions: ‎ 16.51 x 2.54 x 24.13 cm
Price: 2041/-

Just take break in proceedings for a while. If you’re reading this review, benevolently put aside your work for awhile. And envisage the Sahara Desert.

Close your eyes.

You’re in all probability picturing a parched background enclosed in sand dunes. There’s approximately no water. Out in the aloofness, there might be a few camels walking in the blistering sun. It’s not the most welcoming place on earth.

But guess what -- antique artists in Northern Africa once saw an incredibly dissimilar Sahara. Like countless artists, they painted what they saw around them. And as an alternative of what you just imagined, the panorama they re-created on rocks, starting at least 12,000 years ago, was spectacularly unlike.

They made pictures of hippos and giraffes, and other savanna species that need to live near water.

There are even imagery of livestock and grazing animals, like cattle and sheep. While you might perceive these mammals in southern or central Africa today, you’d never find them in the modern Sahara.

But this rock art is all over the place, from the Western Sahara to Saudi Arabia. And it’s also unbelievably precise, which means the artists were actually familiar with the animals they were depicting. For the artists to be that well-informed about hippos and giraffes, those animals had to have lived there.

So does all of this mean that the climate of the Sahara must have been absolutely diverse thousands of years ago?

And the author of this book is not talking about just a few years of extra rain. He’s talking about a climate that was so wet for so long that animals and humans alike, made themselves at home in the middle of the Sahara.

Will the Sahara Become Green Once More? The author asks.

The book is divided into three parts and ends with a petite epilogue.

*Part One provides a concise depiction of how the Sahara came into being and elucidates when and how the Saharan highlands and lowlands were fashioned, culminating in a portrayal of the time when it was last a land of lakes and rivers and was appropriately called the Green Sahara.

Part one is divided into three chapters.

**Chapter 1 sets the scene with an account of how the major elements in the Saharan landscape were fashioned.

**Chapter 2 divulges how dinosaurs once roamed generously across the Sahara, how the sea sometimes covered much of what is now the Sahara, and how it was later covered in high trees that have since been fossilised.

**Chapter 3 depicts the last time the Sahara could accurately be called a ‘green and pleasant land’.

*Part Two looks at how the Sahara became progressively drier, with sand dunes developing from the alluvial sands brought down from the uplands by Desert Rivers. This was a time of constant tug-of-war between flowing water and wind-blown sand.

Part Two is subdivided into four chapters.

**Chapter 4 asks why the Sahara is currently so dry and rejects the notion that humans were the cause of its aridity, pointing out that the Sahara existed as a desert millions of years before humans ever appeared on the scene.

**Chapter 5 considers how the enormous sand seas of the Sahara came into being and note that there is a steady fight between wind and water, with desert rivers jockeying for preeminence and achieving it during times when the climate was wetter, before becoming buried beneath advancing sand dunes during times when sustained dryness led to reactivation of the formerly vegetated and stable dunes.

**Chapter 6 looks at the sometimes astonishingly helpful function of Saharan desert dust in far-flung parts of the world and also shows how dust deposits can be recycled to form potentially fertile alluvial deposits.

**Chapter 7 introduces the earliest humans to move into and occupy the desert during the relatively brief intervals when the Sahara enjoyed a wetter climate.

*Part Three looks at the Sahara today and considers how tremendous climatic events such as long-drawn-out droughts influence human societies and how human activities can exacerbate (or minimise) the brunt of such extreme events.

Part three has three chapters.

**Chapter 8 looks at the causes and consequences of historic droughts, accompanied by the enthralling but tricky predicament of how severe climatic events such as protracted droughts have influenced human societies.

**Chapter 9 investigates the multifaceted issue of desertification, including the diverse and sometimes awkward ways in which it has been delineated.

**Chapter 10 surveys how plants, animals, and human communities have adapted to living in a bone-dry land, where rainfall is untrustworthy and slight, and coping with ambiguity is part of everyday life.

The epilogue asks whether the Sahara could become green once more and what humans can do to live in harmony with our greatest desert as well as with the drier regions of the earth more generally.

Going back to the preliminary dialogue, the numerous rock artists who lived there created a record of this ecological change. But they didn’t record why it all happened. It would be up to scientists from countless different fields to figure that out, thousands of years later.

Geologists would find the first clues, not in the Sahara, but at the base of the Atlantic Ocean. Archaeologists would uncover apparently improbable proof of vibrant societies, in what’s now the desert.

And paleoclimatologists would be able to trace all of these uncanny events back to changes in the movement of our planet.

All of these lines of verification would come together to tell the tale of when the Sahara was green.

In the mid-1800s, a German explorer crossing the Sahara encountered the paintings and engravings left behind by those early Holocene artists.
And he mystified over the disparity between the scenes depicted in the rock art and the desert around it.

Since then, modern geologists have been able to use several lines of verification to confirm what the rock artists saw: Northern Africa was once much wetter, starting somewhere between 15,000 and 11,000 years ago, and ending 5,000 years ago.

Geologists call this span of time the ‘African Humid Period’, but it’s also known as the Green Sahara.

And one of the best pieces of substantiation for a green Sahara comes from close by deep-sea sediment found off the coast of Mauritania.

Geologists have sampled cores of underwater sand and mud to study what’s known as Saharan dust flux, the amount of sediment that was blown off the African continent and into the ocean.

When there was more dust coming off the Sahara, geologists know it was drier, with very little vegetation -- like it is today.

And if there was a smaller amount dust, it would mean that it was wetter. These sediment cores show that there was much less dust - potentially only half as much - coming off northern Africa during this damp period than there is today.

And ancient pollen from the area confirms this. The pollen trapped in those same sediment cores showed an increase in plants like grasses and sedges, and a reduction in desert plants like ephedra, all through the wet period.

So, scientists think that the area where the Sahara is today was covered with vegetation, and that it stretched all the way to the Arabian Peninsula.

So what could turn the biggest hot desert in the world green?

Well, the main driver behind this humid period is actually planetary in scale. At the start of the humid period, recurring changes to both the tilt and orbit of our planet resulted in about 4% to 8% more solar energy hitting the Earth than it gets today, and this warmed up the northern hemisphere.

And when one of the hemispheres gets warmer, prevailing winds tend to move toward it, bringing lots of rain.

That’s because air rises in the warmer area, combining with wind to draw moisture up into the atmosphere. This cycle, called the African monsoon, happens on a small scale every year, during the summer and winter.

And as northern Africa warmed because it was getting more solar energy, summers became hotter and longer than usual. Consequently the African Summer Monsoon was able to reinforce and move farther north over the Sahara desert.

Then, as vegetation grew, the plants held onto moisture better than bare sand could. And that ended up decreasing the land’s albedo - that is, the amount of solar radiation that it reflected.

And this helped keep the northern hemisphere even warmer and wetter. In time, the increased moisture made the Sahara so wet that there were actual bodies of water there.

Recent research found that the Sahara had isolated pockets of lakes and wetlands that formed in natural basins. Some lakes were there long enough that they left behind ancient shorelines, kinda like geological bathtub rings. And these rings show that at least one lake was truly massive -- up to 160 meters deep and covering more 340,000 square kilometers.

That’s bigger than all of the Great Lakes combined! And the location of the rock art confirms the lake levels. Because, the scenes created during the humid period were only made above those ancient shorelines. So, the artists basically created another high water mark that suggests the water was very bottomless indeed.

This damp environment was also home to lots of animals and plants, the kinds that today we see in savannas, not deserts. And they left behind fossils both big and small, even in the driest places.

Take the Ténéré desert, which is part of the southern Sahara. Today it’s known as a desert within a desert. But archaeologists have found evidence that the humid period extended there, too. For instance, there are traces of an ancient lake there that’s full of the remains of crocodiles, hippos, and turtles, as well as massive Nile perch.

Now, along with lakes, there was also a whole river system across the Sahara. In Algeria and Libya, researchers have found river deposits and evidence of human occupation, like fish hooks, around ancient riverbeds. And two contemporary rivers, the Nile and the Niger, also increased their runoff radically.

These riverways allowed the central Sahara to connect to the Atlantic and the Mediterranean, which aided the migration of both humans and non-human animals.

And archaeologists have found that ancient cultures were able to take full advantage of the green Sahara.

Along the waterways where there’s now just sand, there are traces of fireplaces, grinding stones, hunting tools, and even mounds of fish bones.
Researchers have also managed to get radiocarbon dates from organic-rich sediments and artifacts like baskets, which show that human populations throughout the Sahara peaked between 9,000 and 5,000 years ago. And on top of the archaeological evidence, there are even little hints of the African humid period within some cultures of Africa today.

For instance, languages from Mali, in western Africa, and Ethiopia, in eastern Africa, are now very diverse from each other. But they still have similar words for “hippo.” Some linguists think this could mean that people from these cultures once lived in the same place among ... hippos.

Of course, the Sahara returned to a sandy desert at some point.

The rock artists kept painting, and their later art showed that new animals arrived as lakes and rivers began to dry up, and the ecosystem shifted from savannah to desert.

And paleoclimatologists have used the same ocean sediment cores that revealed the start of the green Sahara to figure out when it ended. Dust records show that there was a dramatic decrease in moisture around 5,500 years ago, and that the humid period only took a few centuries to end. When Earth’s orbit shifted once more, the incoming solar energy decreased, and the northern hemisphere cooled down.

This pushed the monsoons south again, closer to where they are now. And sure enough, the archaeological record shows that people who lived in the Sahara abandoned their northern sites first, and then other sites farther south. All things considered, the African humid period ended rapidly, at least in geological terms.

And when it did, people clustered back around the Nile and other water sources, while the Sahara became more like the environment we know today. So, thanks to a partnership between ancient rock artists and modern climate scientists, man has been able to figure out that the Sahara was green not all that long ago.

But what does it tell us about future climate change? Could this happen again?

Well, what we call the African humid period was in fact just the most recent of 230 green periods in the Sahara that have occurred in the past 8 million years!

And since solar radiation is always varying due to natural orbital cycles, it’ll almost positively happen again.

It might be thousands of years from now, and human-induced climate change has to be factored in, too.

Either way, we have every raison d'être to expect that, if and when the Sahara greens up again, future artists will capture that alteration in their work.

They may not do it on rock, but their message will be the same: the world around us is always changing.

Will the Sahara Become Green Once More? We’ll have to wait and see.

In the provisional period go grab this incredible book, containing abundant pictures, tables and figures and tonnes of data and give it a perusal.

Popular science does not always agree with me. But this book did. Most recommended.

[Jim Saunders · Rating 4 out of 5]

This was a deep and detailed book, cool concept but it did not hold my interest, only finished 25%, half the problem was that it was an audio book from Princeton press and I had to use their app to listen and I was having all sorts of issues with it. Paper copy of the book probably would have been a lot better

[Anshuman Swain · Rating 3 out of 5]

3.5 rounded down to 3.

The book has a lot of interesting facts about the general geology, geography and history of the region (in context of the aridity and wetness of the Sahara) and the author doesn't do the best job of putting them in front of the reader.

Some parts seem exceptionally technical and terse while some parts are quite repetitive throughout the book. I love the overall content and premise of the book, though. Learnt a lot.

[Riley T · Rating 5 out of 5]

Loved it and now i want to read more geology books

[Callum Tait · Rating 3 out of 5]

Not very well written at times being a bit repetitive and he only briefly touches on why the Sahara was green right in the epilogue, but was definitely interesting and thoughtful about lifes persistent and the complexity of deserts and causes of desertification.

[Chris Vernon · Rating 3 out of 5]

Well, this book is about as dry as you’d expect an academic book on a desert to be but does do a good job conveying the incredible changes over thousands of years. During the neolithic, the Sahara was a much wetter place (15,000-5,000 years ago), lots of human archaeology and only become the arid place it is today some 4,500 years ago. Humans bore witness to incredible change, change driven primarily by Milankovitch cycles.

[Thomas Beard · Rating 4 out of 5]

Like the Sahara itself: Frequently dry, always fascinating.

[Robert Ritson · Rating 3 out of 5]

Interesting content, but poor style. Read a lot like a lecture, in fact, probably would work better delivered in a lecture hall.

[Christian · Rating 3 out of 5]

Absolutely fascinating information presented drily, which made this short book still a mini slog to get through. Worth it in the end, but work required to get there.

To even consider the Sahara desert (formed seven million years ago) as green, filled with giraffes, hippos and many other roaming animals traversing the series of woodlands and mega rivers flowing through the 5000km of desert we see today boggles the mind.

This book is a perfect example of bringing the reader I to geological time scales, slowing you down and zooming out, helping you remember that you will just be part of a tiny little blip in the earths long and storied past and future. Forces move which you cannot control, so we may as well understand them, work within them, and try not to mess them up too badly.

[Ckelsey · Rating 3 out of 5]

3.5⭐️ You know that friend that was too smart for their own good? And they try to explain something to you, but even their dumbed down version is way over your head - this is that book. And not in a bad way. This is a very densely factual book that you can tell is written by someone exceptionally knowledgeable about the subject. I had to laugh a few times when the author would reference something as “commonly known as…” and proceed to use a word I have never seen in my life.

I’d consider this more of an academic nonfiction than a general nonfiction novel. But if you’re into scientific nonfiction, this is a great read.

[SeaShore · Rating 5 out of 5]

Today we can determine with some confidence that erosion by fast-flowing and highly energetic rivers of what ultimately became the Sahara Desert was at first prolonged and perennial and then became more and more sporadic as progressive desiccation extended its influence across the desert.
The Sahara is a wonderful natural museum. Thanks to its very aridity, delicate prehistoric rock paintings and very ancient fossil trees, some in growth position are beautifully preserved at widely scattered localities across the desert. In addition, the geological evidence of how the Sahara came into being is very accessible at or close to the surface and not hidden beneath a thick mantle of soil and vegetation. The emergence of the Saharan landscape was a gradual process and took place in fits and starts. It began a long time ago, well before the first appearance of complex life-forms about 540 million years ago. Author Martin Williams writes with passion about the Sahara.
The research is immense as he writes on how the Hoggar mountains evolved. With maps he describes the Arak gorges which point to wetter conditions in the past.

The book in its three parts takes us way back in time and then brings the reader to the present.
With quotes such as:
The human intellect cannot grasp the full range of causes that lie behind any phenomena. But the need to discover causes is deeply ingrained in the spirit of man. Leo Tolstoy, War and Peace I understand the author's reasoning as he embarked on this incredible journey.
5 star rating for this well-written book with complete details and references.

The plates includes a colour map of Africa showing the location of Adrar Bous in the heart of the Sahara --- he said it's taken from The Times Atlas of the World 1980. They are all amazing photographs. The El Berbera Oasis, Mauritania desert, western Sahara is appropriate for greenery. Even the Google Earth photography and the NASA images are well worth viewing here in Part II of the book.

Because our planet is about 4.6 billion years old, it's difficult to conceive what was happening to Earth. My curiosity like all humans makes this book so fascinating. Its as if I'm there with all the Scientists looking at the Archaeological digs.
When the dinosaurs roamed the Sahara for almost 200 million years, he said and the dinosaur era ended as we all know when an asteroid collided with Earth about 66 million years ago.

The author quotes Herodotus (484-425 BC) , the Greek historian, known as the Father of History,
The houses are all built of salt-blocks-an indication that there is no rain in this part of Libya; for if it there were, salt walls would collapse.

Paul and Anne Elrich wrote that faulty irrigation, deforestation helped make the Sahara dry but Martin Williams does not agree with this as the Sahara was in existence as adesert millions of years before ancestral humans first began to fashion tools some 2.5 million years ago in the Gona valley.

It is to note here of the possibility of the Sahara getting green again. Scientists at LiveScience report that there might be several ways:

One of the ways to turn parts of the Sahara into a green landscape is with massive solar and wind farms installed. Rainfall could increase in the Sahara and its southern neighbor, the semiarid Sahel, according to a 2018 study.....

Humans are an adaptable species and we can learn from our past, the author concludes. Education is important and living in harmony with all the denizens of our planet is attainable.

[Jeff Rudisel · Rating 4 out of 5]

Between 15,000 and 5,000 years ago the Sahara was occupied by many rivers and large lakes and forests and grassland (including the associated animals).
This was one of many periodic greenings of the Sahara over the last couple of million years.
The next periodic greening is "scheduled" for around 5000 years from now.
Crocodiles, hippos, giraffes, elephants, lions, etc, etc, etc fossils spread all throughout the Sahara, associated with the periodic greenings.

[Lubna · Rating 4 out of 5]

I'd give this a 3.5 star rating. It's definitely an interesting book. For me the natural history of the Sahara is a fascinating and important subject since I come from the Sahara (Egypt). I would have loved to see the desert as a savanna or forest a few millennia ago. I imagine that my Ancient Egyptian ancestors probably saw a very different landscape back then. It's also fascinating to think that it might once again revert to that, but sadly maybe not in our lifetimes.

[Bruce Harbison · Rating 5 out of 5]

I learned so much from this book. The author debunks common misconceptions about the Sahara and why it exists in its present form. He uses his own research and the findings of many others in many scientific disciplines to explain the history of the area and its future. An easy read for the layperson like me and includes many photos, drawings and graphs. I recommend it!

[Laura · Rating 4 out of 5]

I really enjoyed learning more about the Sahara desert!

Parts of the book were more engaging than others. I especially enjoyed the geological explanations and the parts where he described his personal experience doing research in the Sahara. The author includes various hand-drawn diagrams, which I admire.

[The Inquisitive Biologist · Rating 4 out of 5]

When the Sahara Was Green is a well-illustrated and accessible introduction to the surprisingly complex geography of the Sahara. Read my full review at https://inquisitivebiologist.com/2022...

[Ronan Lyons · Rating 4 out of 5]

A good overview of a very interesting topic. All in, the book was probably drawn out a bit, it's not that long but could have been about a third shorter if some repetition had been left out. But still worth reading.

[Torben Mathiassen · Rating 2 out of 5]

Very repetitive and somewhat dry in content. I was hoping for more information on the historical green Desert rather than the origin of present day Sahara. Perhaps that is on me, but nevertheless the book did not live up to expectations.

[Marta Mills · Rating 1 out of 5]

This book was so poorly written and edited that I put it down in disgust and frustration many times. If it wasn't a book club selection, I would have not finished it.

On the upside, I learned a lot about the Sahara, its geologic and historic history.

[Gary · Rating 2 out of 5]

Intellectually excellent, but seriously no fun to read. Those with more than casual interest in climate and geology and their effect on human culture... well, that's me, but I'm afraid you need far far far more than casual interest to enjoy this.

[F.E. Taylor · Rating 4 out of 5]

Whew, finally a story about climate change that man did not create.

[Larry Gundy · Rating 3 out of 5]

OK

[Shelly · Rating 4 out of 5]

Great for learning about the history of the Sahara.

[Andrew · Rating 3 out of 5]

A well-researched an informative book, but significantly more dense and geologically oriented than I expected. It is accessible to the lay reader, but only barely and with great effort.

[Tania · Rating 3 out of 5]

Some parts were fascinating, some parts very dry!