Greenhouse gas

greenhouse gases are gaseous materials, which contribute to the greenhouse effect and both can have a natural and a anthropogenen origin. The most important natural greenhouse gases water vapour (36-70% of the greenhouse effect), carbon dioxide (CO 2; 9-26%) and methane (CH 4; 3-7%) liftthe average temperature at the earth's surface around approximately 30 °C on +15 °C on. Without this natural greenhouse effect the lower atmosphere in the global means would have only -18°, which the spreading of the life (been) would be very hinderlich.

The anthropogene emission ofGreenhouse gases strengthens the natural greenhouse effect. As possible consequence not only a heating up of the average surface temperature of the earth is discussed, but also feared a climatic change.

Table of contents

water vapour, carbon dioxide and other influences

to the natural greenhouse effect contributes the water vapour about 70%. It comes of predominantly the water circulation (ocean - evaporation - precipitation) plus onesmall portion from volcanism. Carbon dioxide and methane have with approximately 25% (CO 2) and/or. about 2% (CH 4) a clearly smaller contribution at the natural greenhouse effect.

The most important anthropogene greenhouse gas is fossil the carbon dioxide from the burnSource of energy. It constitutes about 60% of the greenhouse effect caused by humans. Methane, primarily from the agriculture and mass animal husbandry, contributes approximately 20% to the anthropogenen greenhouse effect. Further artificial greenhouse gases of air are the dinitrogen oxide (laughing gas, N 2 O, contributionabout 6%), fluorocarbons (FKW and/or. H-FKW), sulfur hexafluoride (SF 6) and fluoridated chlorinated hydrocarbons (FCKW).

But humans increase indirectly also the steam content, because the anthropogene heating up increases the evaporation rate. This secondary reinforcement (“positive feedback “) becomes partial throughmore Wolkenbildung compensates. But these effects are only little clarified, because the water vapour is very unequally distributed over the earth and the today's computer models of the atmosphere are fine not yet enough. The complicated equations for wind, currents, evaporation and Strahlungsbilanz, clouds, chemistry, mountain influence etc. need enormous data sets. Many processes are so small-scale that the climatic models are not to be mastered also with large computers.

Abbildung 1: Treibhausgase tragen unterschiedlich stark zum Treibhauseffekt bei. Die Beiträge hängen u.a. vom relativen Treibhauspotential (GWP) und von der Verweildauer in der Atmosphäre ab (für Erläuterungen s.u.)
Illustration 1: Greenhouse gases contribute differently strongly to the greenhouse effect. The contributions hang among other things of the relative greenhouse potential(GWP) and of the period spent in the atmosphere starting from (for explanations see below)

fluoridated greenhouse gases

in Kyoto minutes beside the classical greenhouse gases CO 2, CH 4 and N 2 O greenhouse gases (F-gases), also fluoridated, were taken up, therethese due to their high period spent in the atmosphere a high Treibhauspotenzial possess (S. Illustration 2). To in Kyoto minutes fluoridated greenhouse gases belong Wasserstoffhaltige

  • seized fluorocarbons (HFC and/or. H-FKW): Hydrocarbons, their molecules both fluorine and hydrogen atoms contain
  • Perfluorierte of fluorocarbons (PFCand/or. FKW): Hydrocarbons, their molecules no more hydrogen atoms contain (the hydrogen atoms are replaced with fluorine atoms)
  • sulfur hexafluoride, SF 6.

effect of greenhouse gases

the short-wave solar radiation is reflected at the earth's surface to a large part and as radiant heatagain radiated. Greenhouse gases can absorb the radiant heat due to their chemical nature in different extent and deliver so the warmth into the atmosphere.

The greenhouse effectiveness of a gas, thus as strongly the release of a gas to the greenhouse effect to contribute can, essentially hangsfrom three factors: The mass of gas (emission rate), set free per time unit, the spectroscopic characteristics of the gas, i.e. as strongly it absorbs the radiant heat in certain wavelength coverages, and its retention time in the atmosphere.

The atmospheric retention time is the time, the one materialon the average in the atmosphere remains, before it is removed by chemical or other processes it. The longer the retention time of a greenhouse gas is the higher, is also the theoretical effect.

Abbildung 2: Relative Treibhauspotenziale (GWP) über verschiedene Zeithorizonte; (a) Kohlendioxid (CO2), Methan (CH4) und Lachgas (N2O), (b) Chlorierte oder Flourierte Verbindungen
Illustration 2: Relative Treibhauspotenziale (GWP) over different time horizons;(A) Carbon dioxide (CO 2), methane (CH 4) and laughing gas (N 2 O), (B) chlorinated or Flourierte connections

a measure for the greenhouse effect of a gas per kilogram of emission quantity is the so-called dependent on material. relative Treibhauspotenzial (global warming potential, GWP),in that the absorptive properties and the retention time are considered.

The relative greenhouse potential is one on the carbon dioxide standardized size, with which the effect of a greenhouse gas is compared with the equivalent quantity carbon dioxide. So has for example methane a relative Treibhauspotenzial of21, i.e. 1 kilogram methane has the same greenhouse effect as 21 kilograms carbon dioxide. However these equivalence factors are still afflicted with certain uncertainties.

The relative greenhouse potential is usually referred to a time horizon from 100 years, i.e. it becomes thoseduring one period of 100 years after the emission averaged warming up effect regards. If one refers it to another time horizon, according to the atmospheric period spent, also the relative greenhouse potential changes. A greenhouse gas contains one or more chlorine or fluorine atoms so increaseditself its relative greenhouse potential due to high chemical stability clearly opposite greenhouse gases without halogen atom (e) (see fig. 2) (Source: IPCC: Climate CHANGE 2001: The Scientific basis. Cambridge University press, Cambridge (U.K.) 2001)

regarding the greenhouse effect of Diesel soot represents Marks of Z. Jacobson,Professor of the Stanford university, since 2002 the thesis that the effect of soot from fossil sources of energy and other aerosols likewise supplies a strong contribution beside CO 2 and CH 4 to the Klimwandel. Whether these effects rather a cooling or a oneGround electrode warming promote, is still disputed due to the complex effect connections.

agreement for the decrease of the greenhouse gas missions

in Kyoto minutes was decided therefore an international-law obligatory agreement for the reduction of the anthropogenen output by important greenhouse gases (direct greenhouse gases). Other greenhouse gases, the so-called.indirect greenhouse gases, like e.g.Carbon monoxide, CO, nitrogen oxides, NO x, or volatile hydrocarbons without methane, NMVOC, is regulated in Montreal minutes, because they contribute to the destruction of the ozone layer.

see also

German emission commercial place, greenhouse gas mission mercantile law, Climatic effect of Diesel soot

literature

  • P. Fabian: Carbon dioxide and other greenhouse gases: Air pollution and their climatic effectiveness. Practice of the natural sciences chemistry 45 (2), S. 2 FF. (1996), ISSN 0177-9516
  • anonyms: Greenhouse gas missions do not take world-wide reversal in view.Weekly report - German Institut for economic research 70 (39), S. 577 - 587 (2003), ISSN 0012-1304
  • Eike Roth: “Global environmental problems - causes and solutions”, Friedmann publishing house Munich 2004, ISBN 3-933431-31-X (well readable representation of the Treibhausefektes including its causing and discussion of the argumentsfor and against a anthropogenen influence)
  • Shaviv, Nir J.; Veizer, January: Celestial Driver OF Phanerozoic Climate? In: GSA Today, volume. 13, No. 7, 1. July 2003, S. 4-10

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