Our planet is surrounded by an insulating blanket of gases. It is a protective layer necessary to maintain a global temperature of about 60° Fahrenheit to support most life on Earth.
The most plentiful gas is water vapor that occurs in nature. Others, the greenhouse gases—resulting from human activities—can be harmful. These are carbon dioxide, CO2 (75 percent of the total volume); methane, CH3 (16 percent); nitrous oxide, N2O (6 percent); and fluorocarbons (2 percent).
The wavelength of incoming solar thermal energy lets 70 percent of it pass through atmospheric gases to the planet’s surface. However, the reradiation from the earth’s surface is at a different wavelength, and greenhouse gases trap most of it. The abundance of the gases in the global blanket determine how much heat passes out to space. If too much heat is retained, global warming occurs. This is the greenhouse effect.