greenhouse effect

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greenhouse effect

a theorized change in the earth's climate caused by accumulation of solar heat in the earth's surface and atmosphere. Human activity contributes increasing amounts of the so-called greenhouse gases, such as carbon dioxide, methane, and chlorofluorocarbon, to the atmosphere. Some of the particles and gases in the atmosphere also allow more sunlight to filter through to the earth's surface but reflect much of the radiant infrared energy that otherwise would escape through the atmosphere back into space. See also global warming.

greenhouse effect

Planetary warming as a result of the trapping of solar energy beneath atmospheric gases. The composition and concentration of the gases in the atmosphere influence the earth's surface temperature because some gases more effectively retain heat than others. Fossil fuel combustion, which has increased at a rapid rate since the 1950s, has deposited increasing amounts of carbon dioxide in the upper atmosphere. This is thought to be a contributory factor in global warming, a phenomenon suspected of having widespread effects on all ecosystems. See: global warming; ozone

greenhouse effect

The progressive earth-heating effect resulting from the transparency of the atmosphere to sun (solar) radiation at high frequencies and its relative opacity to energy re-radiated by the earth at a lower, less penetrative, frequency. Water vapour and carbon dioxide are the main elements concerned, and any increase in these, mainly from the burning of fossil fuels, enhances the heating effect. A rise in surface temperature could melt polar ice and cause widespread flooding.

greenhouse effect

  1. an effect occurring in greenhouses in which the glass transmits short wavelengths but absorbs and re-radiates longer wavelengths, thus heating the interior.
  2. the application of this effect to the earth's atmosphere. Infrared radiation tends to be trapped by carbon dioxide and water vapour in the earth's atmosphere and some of it is re-radiated back to the earth's surface.
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html) runaway greenhouse " happens when a planet takes in more energy from the sun than it can expel which results in the surface of the planet warming, which speeds up the warming process further.
The snowball Earth and the runaway greenhouse effect on Venus are examples of such possible instabilities.
Revisiting this classic planetary science scenario with new computer modeling, the astronomers found a lower thermal radiation threshold for the runaway greenhouse process, meaning that stage may be easier to initiate than had been previously thought.
Sagan said that Venus, being closer to the sun than Earth might have suffered from a runaway greenhouse effect.
NASA spacecraft traveling to Venus found an inhospitable planet wrapped in seemingly impenetrable layers of clouds, with a runaway greenhouse condition that had pushed surface temperatures high enough to melt lead.
The carbon dioxide produces a runaway greenhouse effect that makes Venus the hottest planet in the Solar System, hotter even than Mercury.
That having been said, there is no evidence that Earth can experience a runaway greenhouse effect like Venus did, which literally evaporated its oceans.
The question of how Venus, the planet most like Earth in size, gravity, and composition, ended up a toxic hellstew of sulfur dioxide with a runaway greenhouse effect has fascinated scientists for decades.
Astrobiologists have until now thought water was a potential oxygen source only on planets such as Venus, where a runaway greenhouse effect drove temperatures to spiral higher and higher, eventually boiling away the oceans.
If our descendants are still here and want to maintain their civilization, let alone a thriving biosphere, they will intervene to prevent future ice ages and, eventually, the Venus-style runaway greenhouse that will despoil Earth if left to its own devices.
Once you get to this tipping point, you get a lot more water in the atmosphere and because water vapour is a greenhouse gas, that sets this runaway greenhouse effect.