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Series Editor

Françoise Gaill

Mankind and Deserts 1

Deserts, Aridity, Exploration and Conquests

Edited by

Fernand Joly

Guilhem BourriГ©

First published 2020 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc.

Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms and licenses issued by the CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the undermentioned address:

ISTE Ltd

27-37 St George’s Road

London SW19 4EU

UK

www.iste.co.uk (http://www.iste.co.uk)

John Wiley & Sons, Inc.

111 River Street

Hoboken, NJ 07030

USA

www.wiley.com (http://www.wiley.com)

В© ISTE Ltd 2020

The rights of Fernand Joly and Guilhem BourriГ© to be identified as the authors of this work have been asserted by them in accordance with the Copyright, Designs and Patents Act 1988.

Library of Congress Control Number: 2020943974

British Library Cataloguing-in-Publication Data

A CIP record for this book is available from the British Library

ISBN 978-1-78630-630-2

Foreword

Mankind and deserts

Fernand Joly

(#ulink_dd2f2253-ab3c-5c52-840f-c798fe17830a) departed from this world before he was able to complete this book, through which he had hoped to share his experiences of and passion for deserts.

“Yet another book on deserts!” some might think; another book to add to the numerous publications dedicated to these alien and fascinating worlds.

This book, however, is different from earlier books, as can be seen from its title “Mankind and Deserts”. It is based on the singular relationships that are formed between humans and the world of the desert – relationships that are unique because they can be traced back to the very origins of humanity. Indeed, it is from the arid Horn of Africa (East Africa) that large migrations began and it is along the deserts, if not within the deserts themselves, that we find the major cradles of burgeoning historical civilizations. This inhospitable world is also associated with great spiritual leaders such as Moses, Jesus, Mohammed and the Buddha, while serving as the backdrop for adventurers and empire builders from Alexander the Great to Genghis Khan, or from the Incans to the Conquistadors in the Andes and Mexico.

What is this universe that is so barren and yet so mesmerizing?

“All about a word” was how Fernand Joly introduced his book: “What is a desert?” The ambiguity in this word results from the fact that it has been used in different senses across literature and throughout history. For a geographer-writer such as Fernand Joly, the one fact that stood out was that there was no one desert; instead there were multiple deserts, diverse and varied, ranging from Death Valley to the Kalahari, from the Namib to the Atacama or the Gobi desert. Each of these is a unique landscape, whose uniqueness was born out of its position with respect to the general atmospheric circulation, its geographic location with respect to the sea and to its relief features. And yet, transcending all differences, there is one constraint that binds them all together: aridity, defined as a natural physical state characterized by persistent dryness with the corollary of extremely scarce water resources. Both these concepts, aridity and water, are at the heart of the following chapters. Aridity (Chapter 3 (#ufcc7892e-461c-5c3c-a7bd-5e9919c90558)) because it “transcends time and takes over space” and water (Volume 2, Chapters 1 (#uc52e4f55-0d27-5a86-80c3-a25105824ba4)–3 (#ufcc7892e-461c-5c3c-a7bd-5e9919c90558)) because it is the essential resource for all life, especially in the desert. Aridity is distinct from “drought”, which is simply a “period with insufficient rainfall”. Water is seen through the lens of how it appears on land: “wild water”, which flows over slopes in an un-channeled manner (Volume 2, Chapter 1 (#uc52e4f55-0d27-5a86-80c3-a25105824ba4)), under the impact of violent but brief downpours, and “concentrated waters”, i.e. waters “concentrated” into a channel, fed by distant precipitation upstream of the borders of the desert. As can be seen, there is in fact a true hydrography of the arid world. Satellite images, among other sources, offer us clear and accurate reproductions of these systems: fossil hydrographic networks, the legacy of ancient humid periods, a map of intermittent water bodies (Volume 2, Chapter 2 (#u9120ddb8-9dd6-54da-aee2-794a1a43e415)): playas and sabkhas, permanent lakes with fluctuating shorelines, such as Lake Chad or Lake Eyre, or large allogenous rivers (Volume 2, Chapter 3 (#ufcc7892e-461c-5c3c-a7bd-5e9919c90558)) that are born outside the desert but travel through the desert, sustaining life, such as the Colorado, the Niger and the Nile, “the first and most remarkable of rivers in the arid world”.

The role played by salts in hot deserts is rarely discussed in a systematic manner. Guilhem BourriГ©, geochemist and soil scientist at INRAE, has analyzed the origins and nature of these salts and demonstrated how important these salt deposits in the desert are for humans, whether they live off agriculture, livestock or, indeed, the salt trade (Volume 2, Chapter 4).

Chapter 1 (#uc52e4f55-0d27-5a86-80c3-a25105824ba4) of Volume 3, drafted by Joly, was edited after his demise by Yann Callot, a professor at the University Lyon 2 who is a specialist in ergs and dunes. This chapter examines the importance of wind in the desert. Wind, sometimes considered to be more emblematic of a desert than even dryness, counts among the earliest dynamics on Earth, an element that humans have not always been able to control. Indeed, this lack of understanding of wind has sometimes had disastrous consequences for certain projects (see the Green Dam in Algeria).

The final chapter in Volume 3, “Living in the desert”, was taken up by Marc Côte, Professor Emeritus at the University of Provence, who worked as a professor for 20 years at the University of Constantine. He has drawn on his deep knowledge of the land and the people of the Saharan region to present what he calls “The Desert Civilization”.

Finally, it must be noted, with great regret, that, since 2010, “geopolitical turbulences have tended to change the fundamentals, to burn away knowledge and to prevent researchers from keeping in touch with this part of space and humanity.”

Acknowledgments

Most of the illustrations were refined by Г‰liane Leterrier.

Yvette DEWOLF

Honorary Professor at the University Paris VII, Denis Diderot

Paris

August 2020

1В 1 (#ulink_c2733cd7-3cdc-5bee-bacf-bb12e926d180) Professor at the University Paris VII, Denis Diderot, who spent 15 years at the Moroccan Institute of Science in Rabat.

1

Introduction: The Concept of a Desert

“You cannot get the desert into a book any more than a fisherman can haul up the sea with his nets.”

E. Abbey

1.1. All about a word

Desert is one of those familiar yet ambiguous words whose meaning changes depending on people, time and place. It is one of those words whose various meanings can change the very image one has of reality. The personality of the desert is as difficult to capture in everyday language as in the imagination or in scientific research.

The object and the idea, as well as the words to talk about them, exist in humanity’s oldest texts: Babylonian, Egyptian, Hebrew, Chinese etc. In Latinate languages, the word can be traced back to 11th Century Latin. The word first described the result (desertus: deserted, abandoned) of an act of separation (deserere: to desert, to leave). A little later, the word was used to denote a place (desertum: desert), an empty or emptied site, uninhabited or depopulated. The various forms this word has taken over the years reflect this ambiguity.

In Medieval times, hermits would retire to the desert. The term, in this context, denoted both the isolation from other people as well as the barrenness of the place, the solitude and mysticism of the situation. In the 17th Century, “deserts” chiefly evoked the idea of chosen spots that were distant and discreet, where one could “flee into a desert from the approach of humans”. It was a place that was cut off from the world, voluntarily so, as was the case at the Port-Royal-des-Champs convent

(#ulink_80b0685a-c8d2-51e2-94ed-fababc4d5973), or as a result of circumstances, as in the case of the Camisards, French Protestants who lived in an isolated region of France. This connotation of abandonment or exile persists to this day. For example, we say about someone whose words go unheeded that “he is the voice crying in the wilderness” (Isaiah 40:3) and Charles de Gaulle was abandoned politically between 1946 and 1958 in a period that came to be called his “crossing through the desert.”

(#ulink_249eeee0-7f30-5557-9213-3ae4e4286aa0) From the 18th Century onwards, however, it is the geographic sense of the word that prevails. A desert is a seemingly lifeless region, uninhabited, uncultivated, arid (from the Latin arere, to burn, to dry) and sterile due to its dryness. The 19th and 20th Centuries, in turn, saw the rise of new forms of deserts: economic and demographic deserts due to rural flight toward industrial and urban areas. Finally, “desert” is used in a psychological sense to talk about an internal state resulting from a sense of deprivation of the heart or mind.

1.2. Arriving at a definition

1.2.1.What is a desert?