Reflections on Global Warming

Article excerpt

This is certainly an exciting time in our history. We have never been so successful in understanding the mechanisms of nature and, quite positively, reflecting on the consequences of the same achievements, as now. Unfortunately, throughout these times, we also have contributed to the degradation of our environment. The cause is not lost, however, for in the most recent times, we also have become conscious of the problems that we have created and are now beginning to repair, restore, or preserve that which we have disturbed.

As I reflect on these words I look back on the industrial revolution, that great time in our history which began the progress toward modernization. Unfortunately, with that march to development has come a greater rate of the accumulation of greenhouse gases. Given enough time, global warming may occur, if it has not yet happened.

Below, I offer an overview of the difference between the accumulation of greenhouse gases and global warming. There is a distinct difference between the two events, and the occurrence of the former would not necessarily produce the latter. This short discourse will reflect on the consequences of global warming and the things we can do now about it.

GREENHOUSE EFFECT AND GLOBAL WARMING

The greenhouse effect, despite all the controversy surrounding the term, is actually one of the best-established theories in atmospheric science. The greenhouse effect works because some gases and particles in an atmosphere, such as the earth's, preferentially allow sunlight to filter through to the surface of the planet relative to the amount of radiant infrared energy that the atmosphere allows to escape back up to space. The greater the concentration of "greenhouse" material in the atmosphere, the less infrared energy that can escape. Therefore, increasing the amount of greenhouse gases increases the planet's surface temperature by increasing the amount of heat that is trapped in the lowest part of the atmosphere. What is controversial about the greenhouse effect is exactly how much the earth's surface temperature will rise, given a certain increase in a trace greenhouse gas, such as carbon dioxide.

INCREASE IN GLOBAL TEMPERATURE?

Atmospheric carbon-dioxide concentrations have been measured continuously since 1957. The measurements have shown two major signals: a seasonal cycle that reflects the metabolism of terrestrial ecosystems in the Northern Hemisphere, and an accelerating increase in carbon-dioxide tropospheric concentration.

Air bubbles trapped within the Greenland and Antarctic ice caps record concentrations of stable gases at the time that the bubbles were isolated from the atmosphere. Measurements of carbon dioxide in the air demonstrate that concentrations were reasonably constant for several thousand years before the nineteenth century. Carbon-dioxide concentrations then began to increase at an accelerating rate, particularly after 1860. Clearly, when examined closely, there is a strong correlation between the increase in carbon-dioxide concentrations in the atmosphere and the proliferation of the human population and our expansion of energy and resource use.

Other greenhouse gases such as chlorofluorocarbons (CFCs), methane, nitrogen oxides, tropospheric ozone, and so on could together be as important as carbon dioxide in increasing the greenhouse effect. Certainly, projections for increases in the concentration of greenhouse gases based on carbon dioxide alone would underestimate the total greenhouse-gas buildup. Further, since it is not possible to use ordinary scientific procedures to determine whether the increase in greenhouse gases will have a major effect on the earth's temperature, claims about global warming caused by such greenhouse effects are based on theoretical models of the atmosphere. The models are complex, but even scientists who are strong advocates of greenhouse theories admit that the analyses are oversimplified. …