Greenhouse gas
From Envirowiki
A Greenhouse gas is a gas that contributes to the greenhouse effect.
Basically, most gasses with molecules of three or more atoms are greenhouse gasses, of varying intensity. Basically, greenhouse gasses are transparent to high-frequency electromagnetic radiation (such as anything with a higher frequency than visible light), which enters the earth's atmosphere. This radiation then hits objects which are opaque to it, such as most solids, and is reflected, or absorbed. Some of the the energy that is absorbed, is re-radiated as lower-frequency electro magnetic radiation, which has more thermal energy, such as infra-red. Greenhouse gasses are opaque to these lower frequency radiations, which means that they are absorbed, and stay in the atmosphere, or reflected, and re-enter solids, or liquids (i.e. Land or Sea). The resultant effect is an over all warming of the globe.
Glass acts in a similar way, though it's a solid, not a gas. Hence the name.
[edit] 1 Green house gasses
| Gas | Abundance (Year 1750) | Abundance (Year 1998) | Global Warming Potential | Radiative forcing (Wm-2) (change since 1750 due to abundance) |
|---|---|---|---|---|
| Gases relevant to radiative forcing only | ||||
| Carbon dioxide (CO2) | 278 ppm | 365 ppm (131.29%) | 1 | 1.46 |
| Methane (CH4) | 700 ppb | 1745 ppb (249.29%) | 25 | 0.48 |
| Nitrous oxide (N2O) | 270 ppb | 314 ppb (116.30%) | 298 | 0.15 |
| CF4 (CF4) | 40 ppt | 80 ppt (200.00%) | 0 | |
| (C2F6) | 0 | 3 ppt | 0 | |
| Sulphur hexafluoride SF6 | 0 | 4.2 ppt | 22800 | 0 |
| (HFC-23) | 0 | 14 ppt | 0 | |
| HFC-134a (CH2FCF3) | 0 | 7.5 ppt | 1430 | 0 |
| HFC-152a | 0 | 0.5 ppt | 0 | |
| Gases relevant to radiative forcing and ozone depletion | ||||
| CFC-11 (trichlorofluoromethane) (CCl3F) | 0 | 268 ppt | 4750 | 0.07 |
| CFC-12 (CCl2F2) | 0 | 533 ppt | 10900 | 0.17 |
| CFC-13 | 0 | 4 ppt | 0 | |
| CFC-113 (CCl2FFClF2) | 0 | 84 ppt | 6130 | 0.03 |
| CFC-114 | 0 | 15 ppt | 0.01 | |
| CFC-115 | 0 | 7 ppt | 0 | |
| Carbon tetrachloride (CCl4) | 0 | 102 ppt | 1400 | 0.01 |
| Methyl chloroform (CH3CCl3) | 0 | 69 ppt | 146 | 0 |
| HCFC-22 | 0 | 132 ppt | 1810 | 0.03 |
| HCFC-141b (CH3CCl2F) | 0 | 10 ppt | 725 | 0 |
| HCFC-142b (CH3CClF2) | 0 | 11 ppt | 2310 | 0 |
| Halon-1211 (CBrCIF2) | 0 | 3.8 ppt | 1890 | 0 |
| Halon-1301 (CBrCIF3) | 0 | 2.5 ppt | 7140 | 0 |
[edit] 2 See also
[edit] 3 References
- ↑ (2001) "Halocarbons"., Intergovernmental Panel on Climate Change. Retrieved on 2008-09-30.
- ↑ Blasing, T. J. (2008-09). "Current Greenhouse Gas Concentrations". Carbon Dioxide Information Analysis Center. Retrieved on 2008-10-01.
