The Human Impact on the Natural Environment

Professor Andrew Goudie, Director of the China Centre of the University of Oxford, was formerly head of the School of Geography and the Environment, and Master of St Cross College. He has also been President of the International Association of Geomorphologists.

PREFACE TO THE SEVENTH EDITION xi ABOUT THE COMPANION WEBSITE xii PART I: THE PAST AND PRESENT 1 1 INTRODUCTION 3 Chapter Overview 3 The development of ideas 3 The development of human population and stages of cultural development 7 Hunting and gathering 11 Humans as cultivators, keepers and metal workers 13 Modern industrial and urban civilizations 20 Points for review 25 Guide to reading 25 2 THE HUMAN IMPACT ON VEGETATION 26 Chapter Overview 26 Introduction 26 The use of fire 27 Fires: natural and anthropogenic 29 Some consequences of fire suppression 30 Some effects of fire on vegetation 32 The role of grazing 32 Deforestation 34 Secondary rain forest 42 The human role in the creation and maintenance of savanna 43 The spread of desert vegetation on desert margins 46 The maquis of the mediterranean lands 51 The prairies and other mid-latitude and high-altitude grasslands 51 Post-glacial vegetational change in Britain and Europe 53 Lowland heaths 55 Introduction, invasion and explosion 56 Air pollution and its effects on plants 61 Forest decline 63 Miscellaneous causes of plant decline 65 The change in genetic and species diversity 66 Conclusion: threats to plant life 67 Points for review 68 Guide to reading 69 3 HUMAN INFLUENCE ON ANIMALS 70 Chapter Overview 70 Domestication of animals 71 Dispersal and invasions of animals 71 Human influence on the expansion of animal populations 76 Causes of animal contractions and decline: pollution 80 Habitat change and animal decline 83 Other causes of animal decline 86 Animal extinctions in prehistoric times 90 Modern-day extinctions 94 Points for review 101 Guide to reading 102 4 THE HUMAN IMPACT ON THE SOIL 103 Chapter Overview 103 Introduction 103 Salinity: natural sources 104 Human agency and increased salinity 105 Irrigation salinity 105 Dryland salinity 107 Urban salinity 108 Interbasin water transfers 108 Coastal zone salinity 109 Consequences of salinity 110 Reclamation of salt-affected lands 113 Lateritization 113 Accelerated podzolization and acidification 114 Some anthrosols resulting from agriculture and urbanization 115 Soil carbon 116 Soil structure alteration 116 Soil drainage and its impact 118 Soil fertilization 119 Fires and soil quality 120 Soil erosion: general considerations 120 Soil erosion associated with deforestation and agriculture 122 Accelerated wind erosion 126 Soil erosion produced by fi re 128 Soil erosion associated with construction and urbanization 129 Soil conservation 130 Points for review 133 Guide to reading 133 5 THE HUMAN IMPACT ON THE WATERS 134 Chapter Overview 134 Introduction 134 Deliberate modification of rivers 135 Urbanization and its effects on river flow 143 Vegetation modification and its effect on river flow 145 The human impact on lake levels 148 Changes in groundwater conditions 150 Water pollution 155 Chemical pollution by agriculture and other activities 157 Deforestation and its effects on water quality 162 Thermal pollution 164 Pollution with suspended sediments 165 Marine pollution 165 Points for review 168 Guide to reading 168 6 HUMAN AGENCY IN GEOMORPHOLOGY 169 Chapter Overview 169 Introduction 169 Landforms produced by excavation 171 Landforms produced by construction and dumping 173 Sediment transport by rivers 174 Accelerated sedimentation 179 Ground subsidence 184 Arroyo trenching, gullies and peat haggs 187 Accelerated weathering and the tufa decline 191 Accelerated mass movements 192 Deliberate modification of channels 195 Non-deliberate river-channel changes 195 Reactivation and stabilization of sand dunes 201 Accelerated coastal erosion 203 Changing rates of salt marsh accretion 209 The human impact on seismicity and volcanoes 210 Points for review 212 Guide to reading 212 7 THE HUMAN IMPACT ON CLIMATE AND THE ATMOSPHERE 213 Chapter Overview 213 World climates 213 The greenhouse gases carbon dioxide 214 Other gases 216 Ozone depletion and climate change 220 Aerosols 220 Global dimming and global brightening 222 Vegetation and albedo change 222 Forests, irrigation and climate 224 The possible effects of water diversion schemes 225 Lakes 226 Urban climates 226 Deliberate climatic modification 232 Geoengineering 234 Urban air pollution 234 Air pollution: some further effects 238 Stratospheric ozone depletion 243 Conclusions 247 Points for review 248 Guide to reading 248 PART II: THE FUTURE 249 8 THE FUTURE: INTRODUCTION 251 Chapter Overview 251 Introduction 251 Changes in the biosphere 255 Climate and geomorphology 261 Points for review 265 Guide to reading 265 9 THE FUTURE: COASTAL ENVIRONMENTS 266 Chapter Overview 266 Introduction 266 The steric effect 268 Anthropogenic contribution to sea-level change 268 Reduction in lake-water volumes 268 Water impoundment in reservoirs 268 Groundwater mining 269 Urbanization and runoff 269 Deforestation and runoff 269 Wetland losses 269 Irrigation 269 Synthesis 269 Permafrost degradation 270 Melting of glaciers and sea-level rise 270 Ice sheets and sea-level rise 270 How fast are sea levels rising? 271 The amount of sea-level rise by 2100 271 Land subsidence 271 Coral reefs 272 Salt marshes and mangrove swamps 275 River deltas 277 Estuaries 278 Cliffed coasts 279 Sandy beaches 280 The role of sediment starvation 282 Conclusions 282 Points for review 282 Guide to reading 282 10 THE FUTURE: HYDROLOGICAL AND GEOMORPHOLOGICAL IMPACTS 284 Chapter Overview 284 Introduction 284 Rainfall intensity 285 Changes in tropical cyclones 286 Runoff response 287 Cold regions 289 Changes in runoff in the UK 290 Europe 291 Other examples 291 Geomorphological consequences of hydrological and other changes 293 Weathering 295 Points for review 296 Guide to reading 296 11 THE FUTURE: THE CRYOSPHERE 297 Chapter Overview 297 The nature of the cryosphere 297 The polar ice sheets and ice caps 298 Valley glaciers and small ice caps 300 Predicted rates of glacier retreat and some environmental consequences 304 Sea ice in the Arctic and Antarctic 305 Permafrost regions 306 Points for review 310 Guide to reading 310 12 THE FUTURE: DRYLANDS 312 Chapter Overview 312 Introduction 312 Climate changes in the past 314 Future changes in climate in drylands 315 Wind erosivity and erodibility 317 Future dust storm activity 317 Sand dunes 318 Rainfall and runoff 321 Lake levels 322 Sea-level rise and arid zone coastlines 322 Salt weathering 323 Points for review 323 Guide to reading 324 13 CONCLUSION 325 Chapter Overview 325 The power of non-industrial and pre-industrial civilizations 325 The proliferation of impacts 327 Human impacts on the environment in China 330 Are changes reversible? 331 The susceptibility to change 334 Human influence or nature? 336 Global warming and other pressures 337 Into the unknown 338 Points for review 339 Guide to reading 339 GLOSSARY 341 REFERENCES 345 INDEX 406 Colour plate section can be found between pages 196 197