About this book

Five years have passed since the Earth Summit, the important United Nations Conference on Environment and Development which took place in Rio de Janeiro. A milestone has thus been reached on the path towards sustainable development. However, new directions in development can take years, if not decades, to gain a foothold. We have therefore chosen to analyse trends pertaining to health-and-environment issues from the early 1970s - the era of the first United Nations Conference on the Human Environment, held in Stockholm - up to the present, and to make projections from the present until the year 2020. In so doing we are able to provide a fifty-year perspective on health and environment within the context of social and economic development.

Specifically, this book demonstrates that environmental quality is crucial for human health. It does this in two ways: by describing the adverse health effects of environmental hazards and by showing, conversely, how a sound environment can support or "enable" health. In showing trends over time and presenting projections for the future it underscores newly emerging environmental health problems and indicates the type of local and national monitoring and assessment that would improve environmental health management.

The book's intended audience consists of decision-makers, community leaders, scientists and professionals in governmental and nongovernmental organizations who are interested in development issues. It is hoped that this book will inspire professionals working in a variety of development sectors - such as agriculture, industry, environment, aid and planning - and health professionals who wish to become more aware of environmental health issues.

The concept of the environmental cause-and-effect framework provides the book's structure. The first chapter explains the framework and introduces key issues discussed in this book. The basic driving forces behind environmental health problems, such as population growth, economic development and non-sustainable consumption, need to be addressed if we are to secure a healthy environment and sustainable development. Human activities lead to pressures on the environment from sewage, solid waste and pollution, that may eventually affect the quality or state of the environment. If exposed to unhealthy environmental conditions (state), people may experience health effects.

This framework accords with the way in which environmental health scientists have begun to extend their investigation of the environmental causes of ill health beyond the traditional focus on localized hazards to human health. This is because it is becoming increasingly accepted that many of those local hazards are the "downstream" products of large-scale environmental pollution and degradation that are linked to human-induced stresses driven by population growth, economic development and technological forces. Consequently, it is becoming evident that promotion and protection of human health may be undertaken more cost-effectively by implementing measures that limit "upstream" damage to the environment, even though such measures may take some time to yield results. Nevertheless, interventions to control individual exposures to the more downstream hazards may still be preferable if adverse health consequences arising from existing environmental degradation are acute. But in many cases, both approaches will be needed.

The chapters in this book reflect this holistic way of thinking by following the steps of the health-and-environment cause-and-effect framework shown schematically in Fig. 1.3 (see page 9). A more detailed account of this rationale can be found in Chapter 1.

This book is a contribution by WHO to the five-year follow-up to the Earth Summit. This anniversary provides an opportunity to assess the impact made by environmental health activities at local, national and global level during this period. The book systematically brings together quantitative data on health-and-environment linkages at the global level, with examples from regions and countries. Health-and-environment linkages were described in the 1972 WHO report, Health hazards of the human environment, and in the 1992 WHO report, Our planet, our health, but new information and new ways of considering health and environment issues have emerged, and form the basis of this book.

The programmes on Health and Environment at WHO had the main responsibility for the preparation of this book. Many other programmes at WHO headquarters and Regional Offices contributed text and illustrations. The report could not have been completed without the major efforts of a number of WHO staff members and key consultants. Special thanks are due also to the members of the Director-General's Council on the Earth Summit Action Programme for Health and Environment for their input.