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Encyclopedia > Greenhouse effect
A schematic representation of the exchanges of energy between outer space, the Earth's atmosphere, and the Earth surface. The ability of the atmosphere to capture and recycle energy emitted by the Earth surface is the defining characteristic of the greenhouse effect.
A schematic representation of the exchanges of energy between outer space, the Earth's atmosphere, and the Earth surface. The ability of the atmosphere to capture and recycle energy emitted by the Earth surface is the defining characteristic of the greenhouse effect.

The greenhouse effect is the process in which the emission of infrared radiation by the atmosphere warms a planet's surface. The name comes from an incorrect analogy with the warming of air inside a greenhouse compared to the air outside the greenhouse. The greenhouse effect was discovered by Joseph Fourier in 1824 and first investigated quantitatively by Svante Arrhenius in 1896.[1] Image File history File links Greenhouse_Effect. ... Image File history File links Greenhouse_Effect. ... Layers of Atmosphere - not to scale (NOAA)[1] Outer space, sometimes simply called space, refers to the relatively empty regions of the universe outside the atmospheres of celestial bodies. ... Air redirects here. ... In physics, emission is the process by which the energy of a photon is released by another entity, for example, by an atom whose valence electrons make a transition between two electronic energy levels. ... For other uses, see Infrared (disambiguation). ... Atmosphere is the general name for a layer of gases that may surround a material body of sufficient mass. ... This article is about the astronomical term. ... Analogy is both the cognitive process of transferring information from a particular subject (the analogue or source) to another particular subject (the target), and a linguistic expression corresponding to such a process. ... The Royal Greenhouses of Laeken. ... Jean Baptiste Joseph Fourier (March 21, 1768 - May 16, 1830) was a French mathematician and physicist who is best known for initiating the investigation of Fourier series and their application to problems of heat flow. ... Svante August Arrhenius (February 19, 1859 – October 2, 1927) was a Swedish chemist and one of the founders of the science of physical chemistry. ...


The Earth's average surface temperature of 14 °C (57 °F) would otherwise be about -19 °C (-2.2 °F) in the absence of the greenhouse effect.[2] Global warming, a recent warming of the Earth's lower atmosphere, is believed to be the result of an enhanced greenhouse effect due to increased concentrations of greenhouse gases in the atmosphere. In addition to the Earth, Mars and Venus have greenhouse effects. This article is about Earth as a planet. ... Global warming refers to the increase in the average temperature of the Earths near-surface air and oceans in recent decades and its projected continuation. ... Top: Increasing atmospheric levels as measured in the atmosphere and ice cores. ... This article is about the planet. ... This article is about the planet. ...

Contents

Basic mechanism

See also: Radiative forcing
Solar radiation at top of atmosphere and at Earth's surface.
Solar radiation at top of atmosphere and at Earth's surface.
Pattern of absorption bands generated by various greenhouse gases and their impact on both solar radiation and upgoing thermal radiation from the Earth's surface. Note that a greater quantity of upgoing radiation is absorbed, which contributes to the greenhouse effect.
Pattern of absorption bands generated by various greenhouse gases and their impact on both solar radiation and upgoing thermal radiation from the Earth's surface. Note that a greater quantity of upgoing radiation is absorbed, which contributes to the greenhouse effect.

The Earth receives energy from the Sun in the form of radiation. Most of the energy is in visible wavelengths and in infrared wavelengths that are near the visible range (often called "near infrared"). The Earth reflects about 30% of the incoming solar radiation. The remaining 70% is absorbed, warming the land, atmosphere and ocean. The generalised concept of radiative forcing in climate science is any change in the radiation (heat) entering the climate system or changes in radiatively active gases. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Solar irradiance spectrum at top of atmosphere. ... Image File history File links Size of this preview: 595 × 600 pixelsFull resolution (850 × 857 pixel, file size: 75 KB, MIME type: image/png) // Shows how the absorption and recycling of energy by the atmosphere is a defining characteristic of the greenhouse effect. ... Image File history File links Size of this preview: 595 × 600 pixelsFull resolution (850 × 857 pixel, file size: 75 KB, MIME type: image/png) // Shows how the absorption and recycling of energy by the atmosphere is a defining characteristic of the greenhouse effect. ... Solar irradiance spectrum at top of atmosphere. ... For other uses, see Albedo (disambiguation). ...


For the Earth's temperature to be in steady state so that the Earth does not rapidly heat or cool, this absorbed solar radiation must be very closely balanced by energy radiated back to space in the infrared wavelengths. Since the intensity of infrared radiation increases with increasing temperature, one can think of the Earth's temperature as being determined by the infrared flux needed to balance the absorbed solar flux. The visible solar radiation mostly heats the surface, not the atmosphere, whereas most of the infrared radiation escaping to space is emitted from the upper atmosphere, not the surface. The infrared photons emitted by the surface are mostly absorbed in the atmosphere by greenhouse gases and clouds and do not escape directly to space. HELLO EVERYONE!! Steady state is a more general situation than Dynamic equilibrium. ... Solar irradiance spectrum at top of atmosphere. ... For other uses, see Infrared (disambiguation). ... The Stefan-Boltzmann law, also known as Stefans law, states that the total energy radiated per unit surface area of a black body in unit time (known variously as the black-body irradiance, energy flux density, radiant flux, or the emissive power), j*, is directly proportional to the fourth... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... Solar irradiance spectrum at top of atmosphere. ...


The reason this warms the surface is most easily understood by starting with a simplified model of a purely radiative greenhouse effect that ignores energy transfer in the atmosphere by convection (sensible heat transport) and by the evaporation and condensation of water vapor (latent heat transport). In this purely radiative case, one can think of the atmosphere as emitting infrared radiation both upwards and downwards. The upward infrared flux emitted by the surface must balance not only the absorbed solar flux but also this downward infrared flux emitted by the atmosphere. The surface temperature will rise until it generates thermal radiation equivalent to the sum of the incoming solar and infrared radiation. Convection in the most general terms refers to the movement of currents within fluids (i. ... Vaporization redirects here. ... For other uses, see Condensation (disambiguation). ... Water vapor or water vapour (see spelling differences), also aqueous vapor, is the gas phase of water. ... In thermochemistry, latent heat is the amount of energy in the form of heat released or absorbed by a substance during a change of phase (i. ...


A more realistic picture taking into account the convective and latent heat fluxes is somewhat more complex. But the following simple model captures the essence. The starting point is to note that the opacity of the atmosphere to infrared radiation determines the height in the atmosphere from which most of the photons are emitted into space. If the atmosphere is more opaque, the typical photon escaping to space will be emitted from higher in the atmosphere, because one then has to go to higher altitudes to see out to space in the infrared. Since the emission of infrared radiation is a function of temperature, it is the temperature of the atmosphere at this emission level that is effectively determined by the requirement that the emitted flux balance the absorbed solar flux.


But the temperature of the atmosphere generally decreases with height above the surface, at a rate of roughly 6.5 °C per kilometer on average, until one reaches the stratosphere 10-15 km above the surface. (Most infrared photons escaping to space are emitted by the troposphere, the region bounded by the surface and the stratosphere, so we can ignore the stratosphere in this simple picture.) A very simple model, but one that proves to be remarkably useful, involves the assumption that this temperature profile is simply fixed, by the non-radiative energy fluxes. Given the temperature at the emission level of the infrared flux escaping to space, one then computes the surface temperature by increasing temperature at the rate of 6.5 °C per kilometer, the environmental lapse rate, until one reaches the surface. The more opaque the atmosphere, and the higher the emission level of the escaping infrared radiation, the warmer the surface, since one then needs to follow this lapse rate over a larger distance in the vertical. While less intuitive than the purely radiative greenhouse effect, this less familiar radiative-convective picture is the starting point for most discussions of the greenhouse effect in the climate modeling literature. This article is about the stratosphere layer; for the hotel in Las Vegas, Nevada, see Stratosphere Las Vegas. ... Atmosphere diagram showing the mesosphere and other layers. ... The lapse rate is defined as the negative of the rate of change in an atmospheric variable, usually temperature, with height observed while moving upwards through an atmosphere. ... Climate models use quantitative methods to simulate the interactions of the atmosphere, oceans, land surface, and ice. ...


The term "greenhouse effect" is a source of confusion in that actual greenhouses do not warm by this mechanism (see section Real greenhouses). Popular discussions often imply incorrectly that they do; this error is sometimes made even in materials from scientific or governmental agencies (e.g., the U.S. Environmental Protection Agency[3]). A schematic representation of the exchanges of energy between outer space, the Earths atmosphere, and the Earth surface. ...


Greenhouse gases

Main article: Greenhouse gas

Quantum mechanics provides the basis for computing the interactions between molecules and radiation. Most of this interaction occurs when the frequency of the radiation closely matches that of the spectral lines of the molecule, determined by the quantization of the modes of vibration and rotation of the molecule. (The electronic excitations are generally not relevant for infrared radiation, as they require energy larger than that in an infrared photon.) Top: Increasing atmospheric levels as measured in the atmosphere and ice cores. ... For a generally accessible and less technical introduction to the topic, see Introduction to quantum mechanics. ... 3D (left and center) and 2D (right) representations of the terpenoid molecule atisane. ... For other uses, see Frequency (disambiguation). ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ...

Major greenhouse gas trends
Major greenhouse gas trends

The width of a spectral line is an important element in understanding its importance for the absorption of radiation. In the Earth’s atmosphere these spectral widths are primarily determined by “pressure broadening”, which is the distortion of the spectrum due to the collision with another molecule. Most of the infrared absorption in the atmosphere can be thought of as occurring while two molecules are colliding. The absorption due to a photon interacting with a lone molecule is relatively small. This three-body aspect of the problem, one photon and two molecules, makes direct quantum mechanical computation for molecules of interest more challenging. Careful laboratory spectroscopic measurements, rather than ab initio quantum mechanical computations, provide the basis for most of the radiative transfer calculations used in studies of the atmosphere. Global trends in major greenhouse gases. ... Global trends in major greenhouse gases. ... Animation of the dispersion of light as it travels through a triangular prism. ...

Year-over-year increase of atmospheric CO2: In the 1960s, the average annual increase was 37% of what it was in 2000 through 2007.
Year-over-year increase of atmospheric CO2: In the 1960s, the average annual increase was 37% of what it was in 2000 through 2007.[4]

The molecules/atoms that constitute the bulk of the atmosphere: oxygen (O2), nitrogen (N2) and argon (Ar); do not interact with infrared radiation significantly. While the oxygen and nitrogen molecules can vibrate, because of their symmetry these vibrations do not create any transient charge separation. Without such a transient dipole moment, they can neither absorb nor emit infrared radiation. In the Earth’s atmosphere, the dominant infrared absorbing gases are water vapor, carbon dioxide, and ozone (O3). The same molecules are also the dominant infrared emitting molecules. CO2 and O3 have "floppy" vibration motions whose quantum states can be excited by collisions at energies encountered in the atmosphere. For example, carbon dioxide is a linear molecule, but it has an important vibrational mode in which the molecule bends with the carbon in the middle moving one way and the oxygens on the ends moving the other way, creating some charge separation, a dipole moment, thus carbon dioxide molecules can absorb IR radiation. Collisions will immediately transfer this energy to heating the surrounding gas. On the other hand, other CO2 molecules will be vibrationally excited by collisions. Roughly 5% of CO2 molecules are vibrationally excited at room temperature and it is this 5% that radiates. A substantial part of the greenhouse effect due to carbon dioxide exists because this vibration is easily excited by infrared radiation. CO2 has two other vibrational modes. The symmetric stretch does not radiate, and the asymmetric stretch is at too high a frequency to be effectively excited by atmospheric temperature collisions, although it does contribute to absorption of IR radiation. The vibrational modes of water are at too high energies to effectively radiate, but do absorb higher frequency IR radiation. Water vapor has a bent shape. It has a permanent dipole moment (the O atom end is electron rich, and the H atoms electron poor) which means that IR light can be emitted and absorbed during rotational transitions, and these transitions can also be produced by collisional energy transfer. Clouds are also very important infrared absorbers. Therefore, water has multiple effects on infrared radiation, through its vapor phase and through its condensed phases. Other absorbers of significance include methane, nitrous oxide and the chlorofluorocarbons. This article is about the chemical element and its most stable form, or dioxygen. ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... General Name, symbol, number argon, Ar, 18 Chemical series noble gases Group, period, block 18, 3, p Appearance colorless Standard atomic weight 39. ... The Earths magnetic field, which is approximately a dipole. ... Water vapor or water vapour (see spelling differences), also aqueous vapor, is the gas phase of water. ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... For other uses, see Ozone (disambiguation). ... Dipole moment refers to the quality of a system to behave like a dipole. ... Methane is a chemical compound with the molecular formula . ... For other uses, see Nitrous oxide (disambiguation). ... For other uses, see CFC (disambiguation). ...


Discussion of the relative importance of different infrared absorbers is confused by the overlap between the spectral lines due to different gases, widened by pressure broadening. As a result, the absorption due to one gas cannot be thought of as independent of the presence of other gases. One convenient approach is to remove the chosen constituent, leaving all other absorbers, and the temperatures, untouched, and monitoring the infrared radiation escaping to space. The reduction in infrared absorption is then a measure of the importance of that constituent. More precisely, define the greenhouse effect (GE) to be the difference between the infrared radiation that the surface would radiate to space if there were no atmosphere and the actual infrared radiation escaping to space. Then compute the percentage reduction in GE when a constituent is removed. The table below is computed by this method, using a particular 1-dimensional model of the atmosphere. More recent 3D computations lead to similar results.

Gas removed percent reduction in GE
H2O 36%
CO2 9%
O3 3%

(Source: GISS-GCM ModelE simulation) [5]

By this particular measure, water vapor can be thought of as providing 36% of the greenhouse effect, and carbon dioxide 9%, but the effect of removal of both of these constituents will be greater than the total that each reduces the effect, in this case more than 45%. An additional proviso is that these numbers are computed holding the cloud distribution fixed. But removing water vapor from the atmosphere while holding clouds fixed is not likely to be physically relevant. In addition, the effects of a given gas are typically nonlinear in the amount of that gas, since the absorption by the gas at one level in the atmosphere can remove photons that would otherwise interact with the gas at another altitude. The kinds of estimates presented in the table, while often encountered in the controversies surrounding global warming, must be treated with caution. Different estimates found in different sources typically result from different definitions and do not reflect uncertainties in the underlying radiative transfer.


Positive feedback, runaway greenhouse effect and tipping point

The tipping point in global warming is the point at which change due to human activity brings about sufficient new processes in nature to make any human reversal of the change impossible. Some climate scientists believe this will be reached in about 2017 [6], while others, notably James Hansen, NASA's top climate scientist, believe it has already been reached. [7] For the American politician from Idaho, see Jim D. Hansen. ...


When there is a loop of effects such as the concentration of a greenhouse gas itself being a function of temperature, there is a feedback. If the effect is to act in the same direction on temperature it is a positive feedback; and if in the opposite direction it is a negative feedback. Sometimes feedback effects can be on the same cause as the forcing but it can also be via another greenhouse gas or on other effects such as change in ice cover affecting the planet's albedo. Positive feedback is a mechanism by which an output is enhanced. ... Positive feedback is a mechanism by which an output is enhanced. ... This article does not cite any references or sources. ... For other uses, see Albedo (disambiguation). ...


Positive feedbacks do not have to lead to a runaway effect. With radiation from the Earth increasing in proportion to the fourth power of temperature, the feedback effect has to be very strong to cause a runaway effect. An increase in temperature from greenhouse gases leading to increased water vapour which is a greenhouse gas causing further warming is a positive feedback. This cannot be a runaway effect or the runaway effect would have occurred long ago. Positive feedback effects are common and can always exist while runaway effects are much rarer and cannot be operating at all times.


If the effects from the second iteration of the loop of effects is larger than the effects of the first iteration of the loop this will lead to a self perpetuating effect. If this occurs and the feedback only ends after producing a major temperature increase, it is called a runaway greenhouse effect. A runaway feedback could also occur in the opposite direction leading to an ice age. Runaway feedbacks are bound to stop, since infinite temperatures are not observed. They are allowed to stop due to things like a reducing supply of a greenhouse gas or a phase change of the gas or ice cover reducing towards zero or increasing toward a large size that is difficult to increase.


According to the clathrate gun hypothesis a runaway greenhouse effect could be caused by liberation of methane gas from hydrates by global warming if there are sufficient hydrates close to unstable conditions. It has been speculated that the Permian-Triassic extinction event was caused by such a runaway effect. It is also thought that large quantities of methane could be released from the Siberian tundra as it begins to thaw, methane being 21-times more potent a greenhouse gas than carbon dioxide.[8]   Extinction intensity through time: apparent percentage of marine animal genera becoming extinct during any given time interval. ... The Permian-Triassic (P-T or PT) extinction event, sometimes informally called the Great Dying, was an extinction event that occurred approximately 251 million years ago (mya), forming the boundary between the Permian and Triassic geologic periods. ...


A runaway greenhouse effect involving CO2 and water vapor may have occurred on Venus due to its closer proximity to the sun. On Venus today there is little water vapor in the atmosphere. If water vapor did contribute to the warmth of Venus at one time, this water is thought to have escaped to space. Venus is sufficiently strongly heated by the Sun that water vapor can rise much higher in the atmosphere and is split into hydrogen and oxygen by ultraviolet light. The hydrogen can then escape from the atmosphere and the oxygen recombines. Carbon dioxide, the dominant greenhouse gas in the current Venusian atmosphere, likely owes its larger concentration to the weakness of carbon recycling as compared to Earth, where the carbon dioxide emitted from volcanoes is efficiently subducted into the Earth by plate tectonics on geologic time scales.[9][10] This article is about the planet. ... This article is about the chemistry of hydrogen. ... This article is about the chemical element and its most stable form, or dioxygen. ...


Even so, the high temperatures on Venus are only partially caused by carbon dioxide; a major contributor is the thick bank of clouds containing sulphuric acid.[11] Although these clouds give Venus a high reflectivity in the visible region, the Galileo probe showed that the clouds appear black at infrared wavelengths of 2.3 microns due to strong infrared absorption [12].


Anthropogenic greenhouse effect

Main article: Global warming

CO2 production from increased industrial activity (fossil fuel burning) and other human activities such as cement production and tropical deforestation[13] has increased the CO2 concentrations in the atmosphere. Measurements of carbon dioxide amounts from Mauna Loa observatory show that CO2 has increased from about 313 ppm (parts per million) in 1960 to about 375 ppm in 2005. The current observed amount of CO2 exceeds the geological record of CO2 maxima (~300 ppm) from ice core data.[14] Global warming refers to the increase in the average temperature of the Earths near-surface air and oceans in recent decades and its projected continuation. ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ...


Because it is a greenhouse gas, elevated CO2 levels will increase global mean temperature; based on an extensive review of the scientific literature, the Intergovernmental Panel on Climate Change concludes that "most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations".[15] IPCC is the science authority for the UNFCCC The Intergovernmental Panel on Climate Change (IPCC) was established in 1988 by two United Nations organizations, the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP), to evaluate the risk of climate change brought on by humans, based mainly on...


Over the past 800,000 years,[16] ice core data shows unambiguously that carbon dioxide has varied from values as low as 180 parts per million (ppm) to the pre-industrial level of 270ppm.[17] Certain paleoclimatologists consider variations in carbon dioxide to be a fundamental factor in controlling climate variations over this time scale.[18] Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Paleoclimatology is the study of climate change taken on the scale of the entire history of the Earth. ...


Real greenhouses

A modern Greenhouse in RHS Wisley
A modern Greenhouse in RHS Wisley

The term 'greenhouse effect' originally came from the greenhouses used for gardening, but it is a misnomer since greenhouses operate differently.[19][20][21] A greenhouse is built of glass. It heats up mainly because the sun warms the ground inside it and this warms the air in the greenhouse. The air continues to heat because it is confined within the greenhouse, unlike the environment outside the greenhouse where warm air near the surface rises and mixes with cooler air aloft. This can be demonstrated by opening a small window near the roof of a greenhouse: the temperature will drop considerably. It has also been demonstrated experimentally (Wood, 1909): a "greenhouse" built of rock salt (which is transparent to infrared radiation) heats up just as one built of glass does. Greenhouses thus work primarily by preventing convection;[21] the atmospheric greenhouse effect however reduces radiation loss, not convection.[21] It is quite common, however, to find sources that make the erroneous "greenhouse" analogy.[22] [23] Although the primary mechanism for warming greenhouses is the prevention of mixing with the free atmosphere, the radiative properties of the glazing can still be important to commercial growers. With the modern development of new plastic surfaces and glazings for greenhouses, this has permitted construction of greenhouses which selectively control radiation transmittance in order to better control the growing environment.[24] Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (2848 × 2136 pixel, file size: 1. ... Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (2848 × 2136 pixel, file size: 1. ... The Royal Greenhouses of Laeken. ... The Royal Horticultural Societys garden at Wisley in the English county of Surrey south of London, is one of the three most visited paid gardens in the United Kingdom alongside Kew Gardens and Alnwick Garden. ... Convection in the most general terms refers to the movement of currents within fluids (i. ...


See also

The Anti-Greenhouse Effect describes the cooling effect an atmosphere has on the ambient temperature of the planet. ... Note: This Wikipedia article is a work in progress. ... Global dimming is the gradual reduction in the amount of global direct irradiance at the Earths surface that was observed for several decades after the start of systematic measurements in 1950s. ... Global warming refers to the increase in the average temperature of the Earths near-surface air and oceans in recent decades and its projected continuation. ... Variations in CO2, temperature and dust from the Vostok ice core over the last 450,000 years For current global climate change, see Global warming. ...

Footnotes

  1. ^ Annual Reviews (requires registration)
  2. ^ Intergovernmental Panel on Climate Change Fourth Assessment Report. Chapter 1: Historical overview of climate change science. page 97
  3. ^ Redirection to EPA Climate Change Site
  4. ^ Dr. Pieter Tans (3 May 2008) "Annual CO2 mole fraction increase (ppm)" for 1959-2007 National Oceanic and Atmospheric Administration Earth System Research Laboratory, Global Monitoring Division (additional details.)
  5. ^ RealClimate, Water vapour: feedback or forcing?
  6. ^ NASA: Danger Point Closer Than Thought From Warming 'Disastrous Effects' of Global Warming Tipping Points Near, According to New Study. By Bill Blakemore, ABC News, May 29, 2007. Accessed April 2008.
  7. ^ Earth in crisis, warns NASA's top climate scientistPhysOrg.com , April 07, 2008 . Accessed April 2008.
  8. ^ Climate change: 'One degree and we're done for' - earth - 27 September 2006 - New Scientist Environment
  9. ^ Venus - Stuart Robbins and David McDonald
  10. ^ Notes (created by Nick Strobel) for an introductory astronomy courses he teaches.
  11. ^ How Hot Can Venus Get?
  12. ^ NASA Infrared Image of Low Clouds on Venus
  13. ^ IPCC Fourth Assessment Report, Working Group I Report "The Physical Science Basis" Chapter 7
  14. ^ Hansen, J., Climatic Change, 68, 269, 2005 ISSN 0165-0009
  15. ^ IPCC Fourth Assessment Report Synthesis Report: Summary for Policymakers (p. 5)
  16. ^ BBC NEWS | Science/Nature | Deep ice tells long climate story
  17. ^ Chemical & Engineering News: Latest News - Ice Core Record Extended
  18. ^ Bowen, Mark; Thin Ice: Unlocking the Secrets of Climate in the World's Highest Mountains; Owl Books, 2005.
  19. ^ Bad Greenhouse
  20. ^ R. W. Wood: Note on the Theory of the Greenhouse
  21. ^ a b c Schroeder, Daniel V. (2000). An introduction to thermal physics. San Francisco, California: Addison-Wesley, pp. 305-307. ISBN 0-321-27779-1. “... this mechanism is called the greenhouse effect, even though most greenhouses depend primarily on a different mechanism (namely, limiting convective cooling).” 
  22. ^ GP 25 Web Book | Chapter 7
  23. ^ NOAA Paleoclimatology Global Warming - The Story
  24. ^ Greenhous covering systems

is the 123rd day of the year (124th in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance with the Gregorian calendar. ... The National Oceanic and Atmospheric Administration (NOAA) is a scientific agency of the United States Department of Commerce focused on the conditions of the oceans and the atmosphere. ... San Francisco redirects here. ... Pearson can mean Pearson PLC the media conglomerate. ...

References

  • Earth Radiation Budget, http://marine.rutgers.edu/mrs/education/class/yuri/erb.html
  • Fleagle, RG and Businger, JA: An introduction to atmospheric physics, 2nd edition, 1980
  • Fraser, Alistair B., Bad Greenhouse http://www.ems.psu.edu/~fraser/Bad/BadGreenhouse.html
  • Giacomelli, Gene A. and William J. Roberts1, Greenhouse Covering Systems, Rutgers University, downloaded from: http://ag.arizona.edu/ceac/research/archive/HortGlazing.pdfPDF (271 KiB) on 3-30-2005.
  • Ann Henderson-Sellers and McGuffie, K: A climate modelling primer (quote: Greenhouse effect: the effect of the atmosphere in re-readiating longwave radiation back to the surface of the Earth. It has nothing to do with glasshouses, which trap warm air at the surface).
  • Idso, S.B.: Carbon Dioxide: friend or foe, 1982 (quote: ...the phraseology is somewhat in appropriate, since CO2 does not warm the planet in a manner analogous to the way in which a greenhouse keeps its interior warm).
  • Kiehl, J.T., and Trenberth, K. (1997). Earth's annual mean global energy budget, Bulletin of the American Meteorological Society '78' (2), 197–208.
  • Piexoto, JP and Oort, AH: Physics of Climate, American Institute of Physics, 1992 (quote: ...the name water vapor-greenhouse effect is actually a misnomer since heating in the usual greenhouse is due to the reduction of convection)
  • Wood, R.W. (1909). Note on the Theory of the Greenhouse, Philosophical Magazine '17', p319–320. For the text of this online, see http://www.wmconnolley.org.uk/sci/wood_rw.1909.html
  • IPCC assessment reports, see http://www.ipcc.ch/
  • How to kill (almost) all life: the end-Permian extinction event, Michael J. Benton and Richard J. Twitchett, Department of Earth Sciences University of Bristol UK, TRENDS in Ecology and Evolution Vol.18 No.7 July 2003, doi:10.1016/S0169-5347(03)00093-4 (full reprintPDF (506 KiB))
  • Bad Greenhouse http://www.ems.psu.edu/~fraser/Bad/BadGreenhouse.html

“PDF” redirects here. ... A kibibyte (a contraction of kilo binary byte) is a unit of information or computer storage, commonly abbreviated KiB (never kiB). 1 kibibyte = 210 bytes = 1,024 bytes The kibibyte is closely related to the kilobyte, which can be used either as a synonym for kibibyte or to refer to... Professor Ann Henderson-Sellers is the Director of the World Climate Research Programme and was the Director of the Environment Division at ANSTO from 1998 to 2005. ... Climate models use quantitative methods to simulate the interactions of the atmosphere, oceans, land surface, and ice. ... The American Meteorological Society promotes the development and dissemination of information and education on the atmospheric and related oceanic and hydrologic sciences and the advancement of their professional applications. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... “PDF” redirects here. ... A kibibyte (a contraction of kilo binary byte) is a unit of information or computer storage, commonly abbreviated KiB (never kiB). 1 kibibyte = 210 bytes = 1,024 bytes The kibibyte is closely related to the kilobyte, which can be used either as a synonym for kibibyte or to refer to... Global warming refers to the increase in the average temperature of the Earths near-surface air and oceans in recent decades and its projected continuation. ... Variations in CO2, temperature and dust from the Vostok ice core over the last 450,000 years For current global climate change, see Global warming. ... The temperature record shows the fluctuations of the temperature of the atmosphere and the oceans through various spans of time. ... Instrumental global surface temperature measurements; see also [http://www. ... Comparison of ground based (blue) and satellite based (red: UAH; green: RSS) records of temperature variations since 1979. ... The temperature record of the past 1000 years describes the reconstruction of temperature for the last 1000 years on the Northern Hemisphere. ... The website of the National Oceanic and Atmospheric Administration contains detailed data of the annual land and ocean temperature since 1880. ... This article is devoted to temperature changes in Earths environment as determined from geologic evidence on multi-million to billion (109) year time scales. ... National and international science academies and professional societies have assessed the current scientific opinion on climate change, in particular recent global warming. ... Look up anthropogenic in Wiktionary, the free dictionary. ... In common with many other forms of transport, aircraft engines emit polluting gases, contribute to global warming, and cause noise pollution. ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... In IPCC reports, equilibrium climate sensitivity refers to the equilibrium change in global mean surface temperature following a doubling of the atmospheric (equivalent) CO2 concentration. ... Global dimming is the gradual reduction in the amount of global direct irradiance at the Earths surface that was observed for several decades after the start of systematic measurements in 1950s. ... Global warming potential (GWP) is a measure of how much a given mass of greenhouse gas is estimated to contribute to global warming. ... Top: Increasing atmospheric levels as measured in the atmosphere and ice cores. ... The Keeling Curve is a graph measuring the increase in the levels of carbon dioxide in the atmosphere since 1958. ... Land Use, Land-Use Change and Forestry (LULUCF) is a term often used in climate change topics. ... Tokyo, a case of Urban Heat Island. ... For other uses, see Albedo (disambiguation). ... Cloud forcing (sometimes described as cloud radiative forcing) is the difference between the radiation budget components for average cloud conditions and cloud-free conditions. ... A glaciation (a created composite term meaning Glacial Period, referring to the Period or Era of, as well as the process of High Glacial Activity), often called an ice age, is a geological phenomenon in which massive ice sheets form in the Arctic and Antarctic and advance toward the equator. ... Global cooling in general can refer to a cooling of the Earth. ... Chart of ocean surface temperature anomaly [°C] during the last strong El Niño in December 1997 El Niño and La Niña (also written in English as El Nino and La Nina) are major temperature fluctuations in surface waters of the tropical Eastern Pacific Ocean. ... Milankovitch cycles are the collective effect of changes in the Earths movements upon its climate, named after Serbian civil engineer and mathematician Milutin Milanković. The eccentricity, axial tilt, and precession of the Earths orbit vary in several patterns, resulting in 100,000 year ice age cycles of the... Orbital forcing, or Milankovitch theory, describes the effect on climate of slow changes in the tilt of the Earths axis and shape of the orbit. ... The generalised concept of radiative forcing in climate science is any change in the radiation (heat) entering the climate system or changes in radiatively active gases. ... 400 year history of sunspot numbers. ... Cleveland Volcano in the Aleutian Islands of Alaska photographed from the International Space Station For other uses, see Volcano (disambiguation). ... Climate models use quantitative methods to simulate the interactions of the atmosphere, oceans, land surface, and ice. ... General Circulation Models (GCMs) are a class of computer-driven models for weather forecasting and predicting climate change, where they are commonly called Global Climate Models. ... The politics of global warming looks at the current political issues relating to global warming, as well as the historical rise of global warming as a political issue. ... UNFCCC logo. ... IPCC is the science authority for the UNFCCC The Intergovernmental Panel on Climate Change (IPCC) was established in 1988 by two United Nations organizations, the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP), to evaluate the risk of climate change brought on by humans, based mainly on... The global warming controversy is a dispute regarding the nature and consequences of global warming. ... This article lists scientists and former scientists who have stated disagreement with one or more of the principal conclusions of the mainstream scientific assessment of global warming. ... This page is non-encyclopedic and represents the editorial views of notably biased publications, such as Newsweek and Mother Jones. ... Graphical description of risks and impacts from global warming from the Third Assessment Report of the Intergovernmental Panel on Climate Change. ... This article or section does not cite any references or sources. ... Fields outside Benambra, Victoria, Australia suffering from drought conditions A drought is an extended period of months or years when a region notes a deficiency in its water supply. ... As recent estimates of the rate of global warming have increased, so have the financial estimates of the damage costs. ... Chart of ocean surface temperature anomaly [°C] during the last strong El Niño in December 1997 El Niño and La Niña (also written in English as El Nino and La Nina) are major temperature fluctuations in surface waters of the tropical Eastern Pacific Ocean. ... A view down the Whitechuck Glacier in North Cascades National Park in 1973 The same view as seen in 2006, where this branch of glacier retreated 1. ... The extinction risk of climate change -- that is, the expected number of species expected to become extinct due to the effects of global warming -- has been estimated in a 2004 Nature study to be between 15 and 37 percent of known species by 2050. ... Global monthly average total ozone amount Ozone depletion describes two distinct, but related observations: a slow, steady decline of about 4 percent per decade in the total amount of ozone in Earths stratosphere since the late 1970s; and a much larger, but seasonal, decrease in stratospheric ozone over Earth... Change in sea surface pH caused by anthropogenic CO2 between the 1700s and the 1990s Ocean acidification is the name given to the ongoing decrease in the pH of the Earths oceans, caused by their uptake of anthropogenic carbon dioxide from the atmosphere. ... Sea level measurements from 23 long tide gauge records in geologically stable environments show a rise of around 20 centimeters per century (2 mm/year). ... Shutdown or slowdown of the thermohaline circulation is a possible effect of global warming. ... Global carbon dioxide emissions 1800–2000 Global average surface temperature 1850 to 2006 Mitigation of global warming involves taking actions aimed at reducing the extent of global warming. ... The Kyoto Protocol is a protocol to the international Framework Convention on Climate Change with the objective of reducing greenhouse gases that cause climate change. ... CDM directs here. ... Joint implementation (JI) is an arrangement under the Kyoto Protocol allowing industrialised countries with a greenhouse gas reduction commitment (so-called Annex 1 countries) to invest in emission reducing projects in another industrialised country as an alternative to emission reductions in their own countries. ... The European Climate Change Programme (ECCP) was launched in June 2000 by the European Unions European Commission. ... The United Kingdoms Climate Change Programme was launched in November 2000 by the British government in response to its commitment agreed at the 1992 United Nations Conference on Environment and Development (UNCED). ... Crude oil prices, 1994-2007 (not adjusted for inflation) In 2005 the government of Sweden announced their intention to make Sweden the first country to break its dependence on petroleum, natural gas and other ‘fossil raw materials’ by 2020. ... Emissions trading (or cap and trade) is an administrative approach used to control pollution by providing economic incentives for achieving reductions in the emissions of pollutants. ... Emissions trading schemes (also known as ‘cap and trade’ schemes) are one of the policy instruments available for reducing carbon dioxide (CO2) and other greenhouse gases. ... A carbon tax is a tax on energy sources which emit carbon dioxide into the atmosphere. ... Until recently, most carbon offsets were commonly done by planting trees. ... This article deals with carbon credits for international trading. ... A carbon dioxide (CO2) sink is a carbon dioxide reservoir that is increasing in size, and is the opposite of a carbon dioxide source. The main natural sinks are (1) the oceans and (2) plants and other organisms that use photosynthesis to remove carbon from the atmosphere by incorporating it... There are very few or no other articles that link to this one. ... For the physical concepts, see conservation of energy and energy efficiency. ... Efficient energy use, sometimes simply called energy efficiency, is using less energy to provide the same level of energy service. ... Renewable energy effectively utilizes natural resources such as sunlight, wind, tides and geothermal heat, which are naturally replenished. ... Renewable energy commercialization involves three generations of technologies dating back more than 100 years. ... // Renewable energy development covers the advancement, capacity growth, and use of renewable energy sources by humans. ... The soft energy path is an energy use and development strategy delineated and promoted by some energy experts and activists, such as Amory Lovins and Tom Bender; in Canada, David Suzuki has been a very prominent (if less specialized) proponent. ... The G8 Climate Change Roundtable was formed in January 2005 at the World Economic Forum in Davos. ... The issue of human-caused, or anthropogenic, climate change (global warming) is becoming a central focus of the Green movement. ... Adaptation to global warming covers all actions aimed at reducing the negative effects of global warming. ... This article is about structures for water impoundment. ... The Seven Rila Lakes in Rila, Bulgaria are typical representatives of lakes with glacial origin A glacial lake is a lake with origins in a melted glacier. ... Irrigation is the artificial application of water to the soil usually for assisting in growing crops. ... A rainwater tank is a water tank which is used to collect and store rainwater runoff, typically from rooftops. ... Sustainable development is a pattern of resource use that aims to meet human needs while preserving the environment so that these needs can be met not only in the present, but in the indefinite future. ... A tornado in central Oklahoma. ... Global carbon dioxide emissions 1800–2000 Global average surface temperature 1850 to 2006 Avoiding Dangerous Climate Change: A Scientific Symposium on Stabilisation of Greenhouse Gases was a 2005 international conference that redefined the link between atmospheric greenhouse gas concentration, and the 2°C (3. ... LADSS or Land Allocation Decision Support System, is an agricultural land use planning tool being developed at The Macaulay Institute. ... This article serves as a glossary of the most common terms and how they are used. ...


  Results from FactBites:
 
Greenhouse Effect - MSN Encarta (1090 words)
Greenhouse Effect, the capacity of certain gases in the atmosphere to trap heat emitted from the Earth’s surface, thereby insulating and warming the Earth.
Water vapor is the most common greenhouse gas in the atmosphere, accounting for about 60 to 70 percent of the natural greenhouse effect.
However, as human activities increase the concentration of other greenhouse gases in the atmosphere (producing warmer temperatures on Earth), the evaporation of oceans, lakes, and rivers, as well as water evaporation from plants, increase and raise the amount of water vapor in the atmosphere.
greenhouse effect: Definition and Much More from Answers.com (3382 words)
The greenhouse effect, first discovered by Joseph Fourier in 1824, and first investigated quantitatively by Svante Arrhenius in 1896, is the process in which the absorption of infrared radiation by an atmosphere warms a planet.
The key to the greenhouse effect is the fact that the atmosphere is relatively transparent to visible solar radiation but strongly absorbing at the wavelengths of the thermal infrared radiation emitted by the surface and the atmosphere.
The strength of the greenhouse effect is dependent on the concentration of greenhouse gases in the planetary atmosphere.
  More results at FactBites »

 
 

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