Part one of term paper
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 d ...

Part two of term paper
... gases trap and keep near ground level. The effect is comparable to the way in which a greenhouse traps heat, hence the term. Environmental scientists are concerned that changes in the variable contents of the atmosphere--particularly changes caused by human activities--could cause the Earth's surface to warm up to a dangerous degree. Since 1850 there has been a mean rise in global temperature of approximately 1° C (approximately 1.8° F). Even a limited rise in average surface temperature might ...