greenhouse effect

greenhouse effect

noun

Definition of GREENHOUSE EFFECT

: warming of the surface and lower atmosphere of a planet (as Earth or Venus) that is caused by conversion of solar radiation into heat in a process involving selective transmission of short wave solar radiation by the atmosphere, its absorption by the planet's surface, and reradiation as infrared which is absorbed and partly reradiated back to the surface by atmospheric gases

First Known Use of GREENHOUSE EFFECT

1937

greenhouse effect

noun    (Concise Encyclopedia)

Some incoming sunlight is reflected by the Earth's atmosphere and surface, but most is absorbed by …—© Merriam-Webster Inc.

Warming of the Earth's surface and lower atmosphere caused by water vapour, carbon dioxide, and other trace gases in the atmosphere. Visible light from the Sun heats the Earth's surface. Part of this energy is radiated back into the atmosphere in the form of infrared radiation, much of which is absorbed by molecules of carbon dioxide and water vapour in the atmosphere and reradiated toward the surface as more heat. (Despite the name, the greenhouse effect is different from the warming in a greenhouse, where panes of glass allow the passage of visible light but hold heat inside the building by trapping warmed air.) The absorption of infrared radiation causes the Earth's surface and lower atmosphere to warm more than they otherwise would, making the Earth's surface habitable. An increase in atmospheric carbon dioxide caused by widespread combustion of fossil fuels may intensify the greenhouse effect and cause long-term climatic changes. Likewise, an increase in atmospheric concentrations of other trace greenhouse gases such as chlorofluorocarbons, nitrous oxide, and methane resulting from human activities may also intensify the greenhouse effect. From the beginning of the Industrial Revolution through the end of the 20th century, the amount of carbon dioxide in the atmosphere increased 30% and the amount of methane more than doubled. It is also estimated that the U.S. is responsible for about one-fifth of all human-produced greenhouse-gas emissions. See also global warming.