The Human Impact addresses the ways in which human activity has changed and is changing the face of the earth, by examining the human role in natural processes and systems. The fourth edition has been completely revised, reset and updated, contains many new maps, figures and illustrations and has well over 100 references to new research in the 1990s. Among the new and expanded sections of the book are those dealing with marine pollution, deforestation, desertification, plant and animal invasions, climatic change and environmental uncertainty. This incisive account of our environmental predicament has not only proved popular with students throughout the world, but increasingly commands a substantial readership both in the scientific community and among the public at large.