National borders have no meaning for the atmosphere. This was demonstrated to the would by the Chernobyl nuclear the atmosphere in one country soon travels around the world. And so, scientists are now worried about the global effects of air pollution. Research shows, in fact, that the earth's atmosphere is changing in ways that could be destructive to life. Pollution could be a major cause of this.
At the same time, the earth's ability to absorb carbon dioxide has greatly decreased. Absorption of carbon dioxide occurs mainly in areas of thick forest. Those areas are rapidly disappearing as more and more forests are cut down.
The result of the increase of carbon dioxide in the atmosphere is the so-called " greenhouse effect." The carbon dioxide acts like a glass screen, making the sun's heat more intense. There are already sings of global warming, say many scientists. Over the next century, average temperatures could rise by as mush as four degrees centigrade.