The Chinese ideogram for "crisis" combines the character wei, meaning danger, with the character ji, denoting opportunity. This is a good description of our global environment situation. We are dangerously close to pushing biological communities and biophysical processes beyond the point from which they can recover. At the same time, our greatly increased understanding of the natural world and how it works gives us an opportunity to repair the damage we have caused and to find new, more efficient, and more environmentally-friendly ways of providing the goods and services we need. British ecologist, Norman Myers points that the current generation of students has the advantage of being the first in history to have the information, resources, and motivation to do something to solve our environmental crisis. Unfortunately, he adds, if solutions to some of our most pressing problems aren't found quickly, this generation also may be the last to have the chance to do so.

I hope that you will find this book a valuable source of information about our global environment, as well as an inspiration for solutions to the dilemmas we face. Everyone has a role to play in this endeavor. Whether as students, educators, researchers, activists, or consumers, each of us can find ways to contribute in solving our common problems.

This book is intended for use in a one- or two-semester course in Environmental Science, Human Ecology, or Environmental Studies at the college or advanced placement high school level. Because most students who will use this book are freshman or sophomore non-science majors, I have tried to make the text readable and accessible without technical jargon or a presumption of prior science background. At the same time, enough data and depth are presented to make this book suitable for many upper division classes and a valuable resource for students who will keep it in their personal libraries after their formal studies are completed.

I have taught aspects of environmental science in a variety of settings for about 40 years. Although the earliest of these classes focused primarily on natural history and conservation, I found my interests and concerns changing in the 1970s. Two broad areas of environmental science that seemed important to me weren't covered in the existing textbooks. One of these is global concerns. We live in an highly interconnected world; the coal burned in China, or the nuclear waste dumped in the ocean by Russia, or the pesticides used on farm crops in Central America affect all of us. The other area is environmental justice and the human dimensions of environmental issues. Although my original interests in the environment were primarily wilderness and wildlife issues, the Civil Rights movement of the 1960s opened my eyes to the conditions in inner cities and the role of economics, health, policy, and law in environmental concerns. Ecology remains the heart of environmental science but students also need to know something about the roles of human institutions and social sciences to be educated environmental citizens. It's gratifying to see that since the first edition of this book was published in 1990, concerns about environmental ethics and social justice are appearing in other textbooks as well.

Ultimately the aims of this book are to foster attitudes of stewardship and environmental citizenship, and to encourage the goals of economic, ecological, and social sustainability. In the preamble to the United Nations Earth Charter, the authors declare that, "In an increasingly interdependent world, it is imperative that we, the citizens of the Earth, declare our responsibility to one another, the greater community of life, and future generations." Among the principles proposed by the Earth Charter are,

1. Respect Earth and all life, recognizing the interdependence and intrinsic value of all beings.
2. Care for the community of life in all its diversity as a responsibility shared by everyone.
3. Strive to build free, just, participatory, and sustainable communities.
4. Secure peace and Earth's abundance and beauty for present and future generations.

I hope the readers of this book will come to share those goals and to understand the reasons they are so important.

-William P. Cunningham