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In this book, the author describes in simple, non-technical terms the adventures he has experienced during his work as an earth scientist in some of the remote parts of the arid and semi-arid world. His aim in writing this concise account of some of the work he has been involved in over the past fifty years is to try to convey to the non-specialist some of the excitement and fun involved in fieldwork in the drier regions of the world. His studies of the soils, landforms and the recent geological history of arid and semi-arid regions have taken Martin Williams to some remarkable places in Africa, Asia, Australia and the Middle East. Not only are the landscapes themselves often stunningly beautiful, but the contact with people from quite different backgrounds and cultures has been an enriching experience. His work has taken him to places far off the beaten track, whether it be the rugged mountains of Ethiopia and northern China, the sandy deserts of the Sahara and Rajasthan, or the great river valleys of Somalia, central India and the Nile. The chapters that follow are not intended to form a coherent chronological narrative, although they do appear in rough chronological order. They should rather be viewed as vignettes or brief evocative descriptions, much as in the discursive tradition of the wandering Irish storytellers. Acting on the principle that it is not necessary to be solemn to be serious, the author aims to entertain as well as to instruct.

Geography-General --- Geography --- Earth & Environmental Sciences --- Geomorphology --- Geomorphologists --- History. --- Geomorphic geology --- Physiography --- Physical geographers --- Physical geography --- Landforms --- World Regional Geography (Continents, Countries, Regions). --- Popular Science in Geography. --- Physical geography. --- Geography. --- Cosmography --- Earth sciences --- World history

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"The little-known history of how the Sahara was transformed from a green and fertile land into the largest hot desert in the world. 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, fed 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 it was later covered in tall trees. Along the way, Williams addresses many 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 also 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 millions of years, When the Sahara Was Green reveals the desert's surprising past to reflect on its present, as well as its possible future"--

Climatic changes --- Desertification --- Aridization of land --- Desertization --- Climatology --- Deserts --- Changes, Climatic --- Changes in climate --- Climate change --- Climate change science --- Climate changes --- Climate variations --- Climatic change --- Climatic fluctuations --- Climatic variations --- Global climate changes --- Global climatic changes --- Climate change mitigation --- Teleconnections (Climatology) --- Environmental aspects --- Global environmental change --- Sahara --- Climate --- History. --- Sahara Desert --- Africa, North --- Aeolian processes. --- Algae. --- Algeria. --- Alluvium. --- Americas. --- Andes. --- Anthozoa. --- Arid. --- Atlantic Ocean. --- Black coral. --- Bolivia. --- Carbon dioxide. --- Chad Basin. --- Chile. --- Climate change. --- Cnidaria. --- Cnidocyte. --- Coal. --- Coral reef. --- Date palm. --- Dendrochronology. --- Deriba Caldera. --- Desert climate. --- Desert. --- Desertification. --- Drought. --- Dry lake. --- Dry valley. --- Dune. --- Earth materials. --- Earth science. --- Earth's orbit. --- East Africa. --- Ecosystem. --- Ecuadorians. --- El Niño-Southern Oscillation. --- Emblem book. --- Erosion. --- Exploration. --- Far North (South Australia). --- Feather. --- Fertilizer. --- Fire coral. --- Goatskin (material). --- Google Earth. --- Grassland. --- Grazing. --- Great Sand Sea. --- Green development. --- Groundwater. --- Herbicide. --- Herder. --- Hippos. --- Iferouane. --- Inca Empire. --- Indo-Pacific. --- Kufra. --- Lake Chad. --- Land snail. --- Libyan Desert. --- Mauritania. --- Mediterranean Sea. --- Mesa. --- Microclimate. --- Monsoon. --- Neolithic. --- Nile. --- North Africa. --- North America. --- Overgrazing. --- Pastoralism. --- Perennial water. --- Pesticide. --- Photosynthesis. --- Plankton. --- Planula. --- Plate tectonics. --- Pollution. --- Polyp. --- Sahara. --- Sand. --- Savanna. --- Sediment. --- Semi-arid climate. --- Silt. --- Soil. --- Solar energy. --- Stolon. --- Stone tool. --- Surface layer. --- Temperate climate. --- Tentacle. --- The Natural Step. --- Tropics. --- Tunisia. --- Vegetation. --- Weathering. --- West Africa. --- Westerlies. --- Year. --- Paleoclimatology --- SCIENCE / Global Warming & Climate Change --- SCIENCE / History

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"This book reconstructs climatic changes in deserts and their margins at a variety of scales in space and time. It draws upon evidence from land and sea, including desert dunes, wind-blown dust, river and lake sediments, glacial moraines, plant and animal fossils, isotope geochemistry, speleothems, soils, and prehistoric archaeology. The book summarises the Cenozoic evolution of the major deserts of the Americas, Eurasia, Africa and Australia and the causes of historic floods and droughts. The book then considers the causes and consequences of desertification and proposes four key conditions for achieving ecologically sustainable use of natural resources in arid and semi-arid areas. Climate Change in Deserts is an invaluable reference for researchers and advanced students interested in the climate and geomorphology of deserts: geographers, geologists, ecologists, archaeologists, soil scientists, hydrologists, climatologists and natural resource managers."--

Paleoclimatology. --- Arid regions climate. --- Climatic changes. --- Deserts --- Paléoclimatologie --- Climat aride --- Climat --- History. --- Changements

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The end of the Pleistocene (c. 75-15 ka) is a key period for the prehistory of the Nile Valley. The climatic fluctuations documented during this period have led human populations from the Middle and Late Palaeolithic to adapt to a changing Nile. In particular, the global shift to more arid conditions regionally translated into the expansion of the Sahara, the lowering of sea levels and the desiccation of some major eastern African lakes. These climatically-induced environmental changes influenced the behaviour of the Nile —although how exactly is still debated— and its role as an ecological refugium for human populations living in its vicinity. Genetic and fossil evidence highlight a strong population substructure in Africa during this period, suggesting the alternation of phases of major dispersals of modern humans within the continent, as well as out-of and back-into Africa, with phases of relative isolation of populations, which might be linked to the creation of environmental refugia during the climatic fluctuations of this period. Understanding to what extent the technological variability observed in north-eastern Africa between 75,000 and 15,000 years ago is linked to environmental changes and/or possible contacts between different human populations is critical in this context. The best-preserved evidence for past human behavior are archaeological assemblages, most often lithic assemblages. However, the use of different terminologies, whether they refer to cultural or techno-typological entities, hampers any systematic comparison between the Nile Valley on one hand and neighbouring regions on the other hand. An outcome of this practice is the artificial ‘isolation’ of the north-eastern African record from its neighbouring regions. This monograph groups together chapters presenting updated reviews and new data on regional archaeological, palaeoenvironmental, palaeoanthropological and geological records from north-eastern Africa, North Africa, the Levant and…

History & Archaeology --- Vallée du Nil --- Le Levant --- Afrique du Nord --- recherches paléolithiques --- Nile Valley --- North Africa --- palaeolithic research --- the Levant