GC: n
CT: The greenhouse effect refers to circumstances where the short wavelengths of visible light from the sun pass through a transparent medium and are absorbed, but the longer wavelengths of the infrared re-radiation from the heated objects are unable to pass through that medium. The trapping of the long wavelength radiation leads to more heating and a higher resultant temperature. Besides the heating of an automobile by sunlight through the windshield and the namesake example of heating the greenhouse by sunlight passing through sealed, transparent windows, the greenhouse effect has been widely used to describe the trapping of excess heat by the rising concentration of carbon dioxide in the atmosphere. The carbon dioxide strongly absorbs infrared and does not allow as much of it to escape into space.
S: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/grnhse.html (last access: 13 February 2015)
N: 1. greenhouse (n): 1660s, from green + house. Greenhouse effect attested from 1937.
effect (n): mid-14c., “execution or completion (of an act),” from Old French efet (13c., Modern French effet) “result, execution, completion, ending,” from Latin effectus “accomplishment, performance,” from past participle stem of efficere “work out, accomplish,” from ex- “out” + facere “to do”. From French, borrowed into Dutch, German, Scandinavian.
2. The warming of the atmosphere by the trapping of Earth’s longwave radiation being radiated to space.
3. The gases most responsible for this effect are water vapor and carbon dioxide.
4. Greenhouse effect.
The greenhouse effect is a natural process that warms the Earth’s surface. When the Sun’s energy reaches the Earth’s atmosphere, some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases.
Greenhouse gases include water vapour, carbon dioxide, methane, nitrous oxide, ozone and some artificial chemicals such as chlorofluorocarbons (CFCs).
The absorbed energy warms the atmosphere and the surface of the Earth. This process maintains the Earth’s temperature at around 33 degrees Celsius warmer than it would otherwise be, allowing life on Earth to exist.
Enhanced greenhouse effect.
The problem we now face is that human activities – particularly burning fossil fuels (coal, oil and natural gas), agriculture and land clearing – are increasing the concentrations of greenhouse gases. This is the enhanced greenhouse effect, which is contributing to warming of the Earth.
S: 1. OED – http://www.etymonline.com/index.php?allowed_in_frame=0&search=greenhouse+effect&searchmode=none (last access: 13 February 2015). 2 & 3. TERMIUM PLUS (last access: 13 February 2014). 4. http://www.environment.gov.au/climate-change/climate-science/greenhouse-effect (last access: 13 February 2015).
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CR: air pollution, biosphere, carbon dioxide, chlorofluorocarbon, climate change, energy, environment, global warming, greenhouse gas, solar energy, stratosphere, stratospheric ozone, tropospheric ozone.
