Most of you have seen glass greenhouse in which gardeners grow flowers and vegetables during cold weather. While green houses are heated, much of the warmth comes from radiation. Light rays penetrate the glass and strike the soil and other objects in the greenhouse. They are then re-radiated as heat energy, much of which is trapped in the greenhouse.
A similar condition occurs when light rays penetrate the atmosphere and reach the earth’s surface. Here, they are re-radiated as heat energy which is eventually reflected back to the atmosphere. Scientists are concerned about the concentration of carbon dioxide and other pollutants in the atmosphere and the greenhouse effect that might occur. Light penetrates these layers and strikes the earth where it is re-radiated as heat.
The pollutants act as a shield and trap the heat like glass in a greenhouse. Scientists have already noticed a warming trend that may relate to the greenhouse effect. Over a period of time, a rise in the earth’s temperature could melt the Polar Ice Caps and raise the level of the oceans 100 feet. This could flood many of our coastal states. Many crop growing areas could become desert wastelands.
Other scientists fear and opposite effect. In some areas of dense smog, the amount of sunlight reaching the earth has been reduced 25-50 percent. This could bring on a sharp drop in temperature on the earth’s surface and even initiate another Ice Age.