Human Causes of Global Change All the human causes of global environmental change happen through a subset of proximate causes, which directly alter aspects of the environ

Is humans self-interest the driving force behind all environmental problems?

Human Causes of Global Change
All the human causes of global environmental change happen through a subset of proximate causes, which directly alter aspects of the environment in ways that have global effects. We begin this chapter by outlining and illustrating an approach to accounting for the major proximate causes of global change, and then proceed to the more difficult issue of explaining them. Three case studies illustrate the various ways human actions can contribute to global change and provide concrete background for the more theoretical discussion that follows. We have identified specific research needs throughout that discussion. We conclude by stating some principles that follow from current knowledge and some implications for research.

IDENTIFYING THE MAJOR PROXIMATE CAUSES
The important proximate human causes of global change are those with enough impact to significantly alter properties of the global environment of potential concern to humanity. The global environmental properties now of greatest concern include the radiative balance of the earth, the number of living species, and the influx of ultraviolet (UV-B) radiation to the earth’s surface (see also National Research Council, 1990b). In the future, however, the properties of concern to humanity are likely to change—ultra-violet radiation, after all, has been of global concern only since the 1960s. Consequently, researchers need a general system for

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Suggested Citation:”3 Human Causes of Global Change.” National Research Council. 1992. Global Environmental Change: Understanding the Human Dimensions. Washington, DC: The National Academies Press. doi: 10.17226/1792.×

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moving from a concern with important changes in the environment to the identification of the human activities that most seriously affect those changes. This section describes an accounting system that can help to perform the task and illustrates it with a rough and partial accounting of the human causes of global climate change.

A TREE-STRUCTURED ACCOUNTING SYSTEM
A useful accounting system for the human causes of global change has a tree structure in which properties of the global environment are linked to the major human activities that alter them, and in which the activities are divided in turn into their constituent parts or influences. Such an accounting system is helpful for social science because, by beginning with variables known to be important to global environmental change, it anchors the study of human activities to the natural environment and imposes a criterion of impact on the consideration of research directions (see also Clark, 1988). This is important because it can direct the attention of social scientists to the study of the activities with strong impacts on global change.

Because the connections between global environmental change and the concepts of social science are rarely obvious, social scientists who begin with important concepts in their fields have often directed their attention to low-impact human activities (see Stern and Oskamp, 1987, for elaboration). An analysis anchored in the critical physical or biological phenomena can identify research traditions whose relevance to the study of environmental change might otherwise be overlooked. For example, an examination of the actors and decisions with the greatest impact on energy use, air pollution, and solid waste generation showed that, by an impact criterion, studies of the determinants of daily behavior had much less potential to yield useful knowledge than studies of household and corporate investment decisions or of organizational routines in the context of energy use and waste management (Stem and Gardner, 1981a,b). Theories and methods existed for each subject matter in relevant disciplines such as psychology and sociology, but much of the research attention had been misdirected.

The idea of tree-structured accounting can be illustrated by the following sketch of a tree describing the causes of global climate change.

The chief environmental property of concern is the level of greenhouse gases in the atmosphere. The major anthropogenic

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Suggested Citation:“3 Human Causes of Global Change.” National Research Council. 1992. Global Environmental Change: Understanding the Human Dimensions. Washington, DC: The National Academies Press. doi: 10.17226/1792.×

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greenhouse gases, defined in terms of overall impact (amount in the atmosphere times impact per molecule integrated over time), are carbon dioxide (CO2), chlorofluorocarbons (CFCs), methane (CH4), and nitrous oxide (N2O). If the trunk of the tree represents the greenhouse gas-producing effect of all human activities, the limbs can represent the contributing greenhouse gases. Table 3-1 presents the limbs during two different time periods and a projection for a future period.
National Academies of Sciences, Engineering, and Medicine. 1992. Global Environmental Change: Understanding the Human Dimensions. Washington, DC: The National Academies Press. https://doi.org/10.17226/1792.