What are the greenhouse effect and global warming?

The greenhouse effect refers to heat from the sun trapped in the atmosphere by gases such as water vapor and carbon dioxide (CO₂), much like trapped heat from the sun warms the interior of a greenhouse. This trapping of the sun's heat allows for a hospitable living environment with a fairly constant average temperature. Without this naturally occurring greenhouse effect, temperatures would be significantly colder than they are, and we would not be able to survive.

Global warming is an increase in the earth's temperature caused by increased greenhouse gas emissions. Since the last ice age, the temperature of the earth has been pretty stable. However, recent emissions of greenhouse gases such as CO₂ have caused a gradual increase in the earth's temperature. This increased release of CO₂ traps more of the sun's heat in the atmosphere. Greenhouse gases are being emitted more quickly than they can be absorbed in the earth's forests, prairies, and oceans. Scientists generally agree on the continued likely rise in average global temperatures over the next century.

WEB SITES (for more information)
www.epa.gov/globalwarming/emissions