The highest level of ecological integration exists at the global scale. In the modern age, three ecological problems of global scale confront us: human population growth, global climate change, and stratospheric ozone depletion. Each of these global ecological problems has a unique origin, mechanism of action, and effect on the global environment. Yet, all three of these global-scale problems are interrelated.
The exponential or geometric growth of the global human population has far reaching effects on the earth. Increased use of non-renewable natural resources, accelerated rates of species extinction, water and air pollution, desertification, and loss of arable land are some of some of the consequences of an exponentially increasing human population - now at over seven billion human beings. Although the exponential growth of the global human population may be slowing to some extent, the worldwide human population may reach 10 to 12 billion people before leveling off at the end of this century. The rate of human population growth is not distributed evenly around the world. Developed nations exhibit little or no growth; some nations in northwestern Europe, e.g., have declining populations. The highest rates of growth occur in developing nations.
The rising concentration of carbon dioxide in the earth's atmosphere, primarily a result of burning of fossil fuels such as coal and oil, is predicted to raise atmospheric temperatures. As a consequence of atmospheric warming, significant changes in the earth's climate are predicted later in this century.
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Although significant climatic changes have occurred in the past and are the result of natural changes in energy balance processes, human-caused changes are predicted to accelerate the rate of change in the global climate.
The effects of chlorofluorocarbons (CFCs) on the stratospheric ozone layer have been known since the mid-1970s. These compounds catalyze the breakdown of stratospheric ozone and, as a consequence, will increase the penetration of solar UV-B radiation (also known as "sun burning" radiation) to the ground. Since UV-B radiation has the potential to damage DNA and cause injury to a wide variety of organisms, increased solar UV-B radiation may have significant deleterious effects on world ecosystems.
Although each of these global-scale concerns has a different origin and mode of action, these concerns are related in several ways. For example, several of the atmospheric pollutants that increase the breakdown of stratospheric ozone are also chemicals that increase atmospheric warming. In turn, warming of the stratosphere affects the ability of atmospheric pollutants to breakdown ozone. Human population growth and industrialization have increased the use of fossil fuels and the industrial use of CFCs and related compounds, thereby increasing the potential for stratospheric ozone depletion and global climate change.
Featured books and journals
Atmospheric chemistry and global change. 1999. Brasseur, G.P., J.J. Orlando, and G.S. Tyndall. National Center for Atmospheric Research.
Earth system science from biogeochemical cycles to global changes. 2000. Jacobson, M., R.J. Charlson, H. Rodhe, and G.H. Orians. Academic Press.
Ecological Society of
America
British Ecological Society
Ecosphere
Global
Biogeochemical Cycles
Global Change Biology
Oceanography