Beginning of Essay
(After a lot of reading and hunting around on the net, I found a great deal of information on this topic. I had never really researched on it before so wanted to make sure that calculations agreed from report to report. Most of them did so I will base my answer on ....

Middle of Essay
.... always died of old age ...) FIRST of all, it is important to know that the "greenhouse effect" is not a bad thing in itself. In fact, this planet would be a life-less waste land without its natural greenhouseing. There are a collection of gases called "greenhouse gases," which are water vapor, carbine dioxide, ozone, methane, nitrous oxide, and chlorofluorocarbons (CFC). Without the natural greenhouse effect, the surface temperature of our planet would be an average of -18°C (zero degrees F). The mixture of these gases have remained pretty much stable over the centuries and have kept us all living. But here we are in the late nineties, and we ....