Global Warming and the Greenhouse Effect Essay

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Global Warming and the Greenhouse Effect

The greenhouse effect, in environmental science, is a popular term for the effect that certain variable constituents of the Earth's lower atmosphere have on surface temperatures. It has been known since 1896 that Earth has been warmed by a blanket of gasses (This is called the "greenhouse effect."). The gases--water vapor (H2O), carbon dioxide (CO2), and methane (CH4)--keep ground temperatures at a global average of about 15 degrees C (60 degrees F). Without them the average would be below the freezing point of water. The gases have this effect because as incoming solar radiation strikes the surface, the surface gives off infrared radiation, or heat, that the gases trap and keep near ground
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However, variations in the atmosphere's CO2 content are what have played a major role in past climatic changes. In recent decades there has been a global increase in atmospheric CO2, largely as a result of the burning of fossil fuels. If the many other determinants of the Earth's present global climate remain more or less constant, the CO2 increase should raise the average temperature at the Earth's surface. As the atmosphere warmed, the amount of H2O would probably also increase, because warm air can contain more H2O than can cooler air. This process might go on indefinitely. On the other hand, reverse processes could develop such as increased cloud cover and increased absorption of CO2 by phytoplankton in the ocean. These would act as natural feedbacks, lowering temperatures.8 In fact, a great deal remains unknown about the cycling of carbon through the environment, and in particular about the role of oceans in this atmospheric carbon cycle.

Many further uncertainties exist in greenhouse-effect studies because the temperature records being used tend to represent the warmer urban areas rather than the global environment. Beyond that, the effects of CH4, natural trace gases, and industrial pollutants--indeed, the complex interactions of all of these climate controls working together--are only beginning to be understood by workers in the environmental sciences.2 Despite such
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