Global ecology

The book begins on the theme of the biosphere, its nature, extent, and some of its functional properties. This is followed by chapters with op posing views on the state of the world-the pessimistic projections of Global 2000 and the optimistic views of Julian Simon and Herman Kahn. These illustrate the range of opinions now available on global futures and human

prospects. The second section deals with ecological principles and trends-topics such as biogeochemical cycles, interactions of the atmosphere and hydrosphere, and measurable trends in global ecology. These chapters go beyond introductory textbooks, and they emphasize current areas of research. Chapter 8 provides one of the best real data assessments on worldwide environmental trends by which we can evaluate the pessimism and optimism expressed in preceding chapters.

The third section deals with human impacts on the biosphere-air and water pollution, land degradation, soil erosion, world food supplies, tropical deforestation, and desertification. These topics illustrate both ecologic and economic effects of human activities. Although most of the chapters in Sections II and III deal with the terrestrial environment, quite appropriately since this is where we live, Chapters 7 and 12 on marine ecology recognize that we do live on a watery planet, with more than 70% of the earth's surface covered by oceans, seas, and ice. The fourth section focuses on human populations-demography, population trends, poverty, and world health, all representing a directly humanistic approach to global ecology. We sometimes forget that our own populations reflect global environmental conditions as well as alter them. This is especially true in the area of world health. The book ends with a discussion of human prospects, biological diver sity, environmental consequences of war, nuclear winter, and the roles of science and technology in guiding global futures.