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Stratospheric ozone depletion and UV radiation

Many of the most readily identified causes of these changes are human activities. Major contributors to the accumulation of greenhouse gases in the atmosphere include the burning of fossil fuels for heating and energy generation and the use of chlorofluorocarbons (CFCs) as coolants and aerosols. The burning of fossil fuels is also a major cause of acid rain, which is formed when airborne sulfur dioxide and nitrogen oxides combine with water vapor. Air pollutants include ozone, carbon monoxide, lead, sulfur dioxide, nitrogen dioxide, and particulates—all by-products of industrial and energy-generation processes. Stratospheric ozone thinning is believed to be a direct consequence of the accumulation of CFCs in the upper atmosphere.

Major threats to clean, fresh-water supplies include contamination not only from precipitation of chemical emissions that have accumulated in the atmosphere but also from agricultural runoff containing pesticides and fertilizers, from waste discharges into rivers, from salt used for highway deicing, from hazardous wastes disposed of improperly, and from leachate from municipal dumps. Deforestation is the consequence both of converting forests to farmland and residential and business areas and of overharvesting timber. Wetland loss results from the “reclamation” of wetlands for commercial development. Desertification, the transformation of arable land into land on which crops will no longer grow, has a variety of causes, including overgrazing and the salinization of soil from excessive irrigation.

Since the human activities that are implicated in detrimental environmental change are aimed at satisfying human needs and desires, those activities can only be expected to increase as the population grows. And population growth, worldwide, is expected to continue for the near future at

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Suggested Citation:”5 Environmental Change.” National Research Council. 1995. Emerging Needs and Opportunities for Human Factors Research. Washington, DC: The National Academies Press. doi: 10.17226/4940. ×
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least, at something like its current rate, which would yield a doubling of the current number of about 6 billion before the middle of the twenty-first century. Moreover, if present trends continue, the pressures on the environment are likely to grow faster than the population. During the twentieth century, worldwide energy consumption has increased by a factor of about 15 and the total population has increased by a factor of about 3.5, which is to say that, compared with 1900, there are about 3.5 times as many of us now and each of us uses, on average, 4 times as much energy (Gibbons et al., 1989). There is now an enormous disparity between the per capita use of energy in the industrialized world and in developing countries; we can expect that the desire of the developing countries to close this gap will create a strong impetus to increase the average use worldwide.

In short, there is much evidence that human behavior can adversely affect the natural environment in a variety of ways and that the forces that motivate environmentally detrimental behavior are likely to become even stronger in the future. There is a need to better understand the coupling of behavior and environmental change and how to mitigate the undesirable effects.