When The Sahara Was Green By Martin Williams — Review

The fascinating but little-known history of how the Sahara was transformed from a pleasant green and fertile land into the largest hot desert in the world.
Green Sahara. (Collage by Kuat Abeshev. Credits for images used in the collage: Photo by David Clode ... More on Unsplash; Photo by Mark Eder on Unsplash; Photo by David Clode on Unsplash.)
It is probably unimaginable to most of us to learn that there was a time only 5,000 years ago, when the Sahara was not a desert at all. Instead, it was a green and fertile woodland and vast grassy savannah that hosted a plethora of lakes and rivers, and home to countless dinosaurs that roamed freely across the land. Later, prehistoric hunters and farmers lived in the Sahara alongside a veritable zoo of iconic African wildlife, including elephants, giraffes, hippos, a variety of gazelles, Nile perch, crocodiles, aurochs, Neolithic cattle, turtles, and an enormous collection of large trees and plants.
All this, according to earth scientist Martin Williams, an Emeritus Professor at the University of Adelaide and a world authority on climatic and environmental change. In his captivating memoir, When the Sahara Was Green: How Our Greatest Desert Came to Be (Princeton University Press; 2023/2024), Professor Williams shares stories from his lifetime devoted to researching and exploring the Sahara Desert to provide us with a fascinating and readable overview of the surprisingly complex climate and geography of the Sahara. Professor Williams discusses the evidence that supports the answers that scientists know to some very basic questions, including; why was the Sahara previously much wetter than it is now, and will it become wetter again? ('Not for a long time,' p. 180). Did humans contribute to the Sahara's desertification? ('NO!' Pp. 143; 144-145). And where does all that sand come from? (Chapters 5 & 6).
Paperback cover: When the Sahara Was Green by Martin Williams (Princeton University Press, ... More 2023/2024).
Professor Williams points out that the Sahara Desert isn't actually all sand. Contrary to popular belief, sandy areas comprise only about 20% of the Sahara. Much of the Sahara consists of gravel along with extensive plateaus and – yes – rocky mountains.
Divided into three parts, this readable history begins when the supercontinent Gondwana first appeared 7 million years ago, and follows its journey as it broke apart into major land masses: South America, Africa, Antarctica, Australia, Zealandia, Arabia, and the Indian subcontinent. Professor Williams also explores and explains ancient glaciations, historic sea level fluctuations, the geological and climatological reasons for why the Green Sahara dried out and became a desert, and how the very old basement rock underlying Africa still influences what happens on the surface today.
Compelling writing and profound knowledge are carefully combined with deep history, decades of field work, personal observations and experiences. In this meticulously researched book, Professor Williams explores a wide variety of topics from the geological and climatic changes that influenced human evolution and created the Sahara as we know it, to modern environmental and political issues that confront us today. Throughout the entire book, Professor Williams' fundamental knowledge of the region's geology, archaeology and ecology makes this book rewarding and fascinating reading.
The book includes lots of maps, photographs, drawings and diagrams to illustrate the regions and concepts that Professor Williams discusses in the text. One piece of advice I have is to use sticky notes as bookmarkers for maps 1, 2 and 3 because you will be referring to these maps many times as you read the book.
I was perhaps most surprised by all the ancient human artifacts, pottery – some packed with fossilized fruits – arrowheads and other stone tools, and even some fossilized bones from ancient humans as well as the animals they interacted with, just lying on the surface of the sand or gravel. Mind-boggling. The anecdotes and first-hand experiences described herein make for tremendously compelling storytelling, and could only come from someone who has spent his life researching and working in the region.
Professor Williams exhibits an astonishing depth and breadth of knowledge throughout the entire book, and is generous with his explanations of the scientific evidence to the reader. The Sahara Desert is a powerful warning of what the entire world is facing and the conclusions the author reaches have far-reaching implications beyond north Africa, especially as climate change progresses ever more rapidly. This important book is highly recommended for everyone interested in environmental history or law, or prehistory, and students of any of the sciences will learn a lot from reading it.
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