ABSTRACT
To illustrate the importance of outcome uncertainty in environmental-policy choice, this chapter considers two archetypal problems: human exposure to toxic chemicals and global or regional ecosystem modification. Chemicals may be released to the general environment through air or water emissions from stationary industrial facilities, from mobile automobile and other internal-combustion engines, from consumer appliances such as gas- or wood-burning stoves, from natural sources such as radon seepage from the earth, and from other sources. One archetypal environmental-policy problem concerns human activities that substantially alter global or regional ecosystems. Human exposure to the pollutants or their products depends on the distribution of these substances through environmental media and on behavioral patterns. Environmental-policy making does not generally call for once and final decisions. The relationships between human activities, environmental conditions, and human welfare are continuing and understanding of these relationships is likely to improve over time. The chapter also presents an overview of the key concepts discussed in this book.
