Editor's Introduction

Environmental problems do not occur in isolation from each other; in fact there is often an ironically cruel symmetry about them. For example, carbon dioxide (CO2) is the indispensable feedstock for life on Earth and the amount of CO2 in the atmosphere regulates the process known as “the greenhouse effect.” This effect is a fundamental geophysical mechanism that warms the lower atmosphere and thus allows life to exist on the surface. The buildup of CO2 could thus be beneficial, stimulating plant growth. However, the very rapid pace of growth of atmospheric CO2 (and other greenhouse gases), occurring at present by many human activities, are expected to upset the stability of traditional climates and dramatically alter the conditions that support already strained human societies and natural ecosystems.

Environmental problems can not be separated from human activities. Chlorofluorocarbons (CFCs) are an entirely man-made family of industrial gases. For more than three decades, these inexpensive and versatile compounds — which are neither toxic, nor corrosive, nor explosive — were touted as the “miracle drugs” of the chemical industry. Now we know that they are an important cause of stratospheric ozone depletion and also contribute to the greenhouse effect. As a consequence of our expanding knowledge of their environmental effects, the traditional (and most dangerous) varieties of these compounds are the focus of an internationally agreed phaseout programme.

And finally, environmental activities are inextricably woven into a complex tapestry of interactive atmospheric and biological mechananisms. These natural feedback processes have no regard for international conventions, legal boundaries, or political ideologies.