Environmental planning, a term that would have been virtually unrecognizable 50 years ago, emerged as a field at the end of the 1960s. Its emergence can be traced to two separate background forces. First, with the growth of population and prosperity, humanity had acquired more ability to damage the environment. More people, more kilowatt hours of electricity generated, more vehicle miles driven, more acres covered with paving and structures— all meant that the natural environment was at greater risk. Second, and more important according to some, were changes in what we produced and the way we produced it. Around 1940 there began a revolution in the types of materials we produced and used. Up until that time most of our materials were naturally occurring substances, though often processed and modified in some way. Since then we have increasingly relied on substances that have never before existed, that often have some degree of toxicity, and for which natural pathways of degradation do not exist. For example, in a very influential book, Silent Spring, Rachel Carson argued that DDT (a compound that had been known for some decades but came into use only about the time of World War II) was entering the food chain, with all sorts of dire consequences both to the ecosystem in general and to humans— who eat fairly high up on the food chain—in particular.5 Barry Commoner in The Closing Circle (a title whose ominous ring fits the tone of the book well) cited a long list of changes in products and processes with adverse environmental consequences; for example, pesticides, chemical rather than natural fertilizers, and the increasing use of plastics like polyethylene for which natural degradative pathways do not exist.6
By the end of the 1960s, mounting concern with the effect of our impact on the environment resulted in the passage of the National Environmental Policy Act (NEPA), and the creation of the Environmental Protection Agency (EPA). The act also required the filing of an environmental impact statement (EIS) for a project involving substantial amounts of federal funding, a stipulation that more than any other single event brought the field of environmental planning into being. Simply complying with the requirement that an EIS accompany a request for federal funding created employment for large numbers of environmental planners. In the following years many states passed laws analogous to NEPA, often referred to as "little NEPA" acts. Congress passed numerous other pieces of environmental legislation such as the Clean Air Act and the Toxic Substances Control Act. In each case, the studies and planning required to comply with the requirements of the law expanded the field of environmental planning. Increasing consciousness of environmental issues has also prompted agencies handling traditional land-use planning to consider environmental aspects that a few years ago were often ignored in the planning process. The subject is pursued further in Chapter 15.
A subfield of environmental planning, energy planning, abruptly came into being in 1973 following the Arab-Israeli War. The oil embargo that followed the war very quickly caused a quadrupling of crude oil prices and a 50 percent increase in the cost of gasoline. In the next two decades, interest in energy planning waxed and waned with the rise and fall of oil prices. In recent years interest has been consistently high, not so much because of energy prices but because of concern with reducing carbon dioxide emissions.