Greenhouse effect

The "greenhouse effect" refers to the retention of warmth at the Earth's surface and in the atmosphere which results when gas molecules prevent the escape of infrared radiation into outer space.

These "greenhouse gas" molecules (principally water, carbon dioxide, and methane) absorb and re-emit longwave infrared rays emitted from the earth's surface into the atmosphere (see radiational cooling). Sunlight falling on the surface of a planet is primarily in the visible part of the spectrum. However, the reflection of light from the surface tends to produce light of longer wavelength called infrared (IR) radiation (also known as radiant heat; IR radiation is the heat that we sense being radiated from a hot surface like a hot piece of metal).

Richard Lindzen wrote:

The main absorbers of infrared in the atmosphere are water vapor and clouds. Even if all other greenhouse gases (such as carbon dioxide and methane) were to disappear, we would still be left with over 98 percent of the current greenhouse effect. [1]

This insulating effect has been compared to a blanket or to the glass walls and roof of a greenhouse, but the process is not the same.

See also

• Runaway greenhouse effect

Bibliography

Wile, Jay L. Exploring Creation With Physical Science. Apologia Educational Ministries, Inc. 1999, 2000.