Within the last decade many people have become increasingly concerned with our future on this planet. Aside from its profound philosophical aspects, the subject also attracts interdisciplinary scientific interest and, of course, international concern. This volume, Global Climate Change: Human and Natural Influences, is a result of that concern.
Because of the magnitude of our concern, it seemed appropriate to deal with the global environment from a scientific viewpoint and to review the current status of a variety of issues. We focused on the interaction of the environment--atmosphere, land, water and especially ocean--with ecological resources. These resources provide us with a healthful environment in which to live and with food, probably the most basic resource.
This volume deals with three categories of problems. The first arises as the result of inadvertent byproducts of human activities. That is, byproducts are not intended to occur, but their occurrence has important woldwide effects that manifest themselves in chemical changes and perhaps other changes that we do not yet understand.
The second category has to do with modifications of the environment which are purposeful, that is, directed by humans, but with long-range problems that are not desirable. For example, agriculture is certainly a major modification of the land environment. It has many desirable consequences--it provides us with food--but has long-range implications which need to be examined. The provision and transport of water is another important modification. The discharge of wastes into the ocean, the ultimate sink, is something that we need to be concerned about.
Finally, the third category deals with ""natural"" global environmental issues, i.e., ""natural"" in the sense that they are not controlled by human intervention but do have important consequences for us. Catastrophic events, of course, are easy to recognize. These are principally volcanic eruptions, earthquakes, and natural disasters which we have not experienced recently, such as impacts of large meteorites or comets. These events can kill populations of living creatures on this earth and are therefore cataclysmic. But we also have gradual natural changes that are difficult to recognize because they are very slow, e.g., changes in the climate. As we will discuss later, there are also many changes in the environment brought about by living creatures other than human beings.