What Exactly is the Greenhouse Effect?
Dear EarthTalk: What exactly is the “greenhouse effect” and how is it a bad thing? — Suanne Gladstone, Queensland, Australia The “greenhouse effect” occurs naturally when heat from the sun enters our atmosphere but cannot escape because it is blocked by water vapor, carbon dioxide and other airborne elements, thereby causing a warming of the Earth. Without a natural greenhouse effect, the average temperature of the Earth would be about zero degrees Fahrenheit instead of its present 57 degrees Fahrenheit. But increasing amounts of pollutants from manufacturing and power plants, agricultural activities, automobiles and other sources that burn fossil fuels have led to an excessive build-up in the Earth s atmosphere of greenhouse gases such as carbon dioxide, nitrous oxides and methane. Scientists believe that this build-up is exaggerating the naturally occurring greenhouse effect and is to blame for the average temperature on Earth rising by more than one degree over the last century. Th
