Water Vapor And Methane on Global Warming
Schematic presentation of the elements of water cycle.
The amount of water vapor in the atmosphere depends solely on atmospheric thermodynamics. The amount of water vapor that air can contain depends on the saturation pressure, which in turn depends on temperature. Saturation pressure of water vapor in the atmosphere can be expressed by simple theoretical formula, or more precisely, by semi-empiric formulas (formulas whose constants were determined from experimental observations), as Wexler relations. Saturation vapor pressure of water increases rapidly with temperature, so that at 10 ° C 1 kg of dry air can absorb 7.73 g of water at a temperature of 30 ° C can absorb 27.52 g.
Local pressure vapor (basically their local concentration) determines the speed of evaporation. A dry wind removes water vapor formed, allowing a new amounts of water evaporation, which explains the drying effect of wind. In turn, the wind is generated by atmospheric pressure differences, differences that arise due to differences in density of the air density which depends on temperature. It is noted that they are responsible for temperature variations in the amount of water vapor in the atmosphere. The greenhouse effect of water vapor is natural but there is no technical possibility to influence the amount of water vapor in the atmosphere than an attempt to reduce temperature. Note that evaporation is reversible by lowering the temperature of water vapor condenses, an effect observed in autumn and winter, when temperatures decrease in annual rainfall increases.
From the above, although water vapor is the main greenhouse gas, not on it should be taken for global warming.
It is another gaseous chemical combination that is carbon in the atmosphere.
Equal volume quantities, produces methane greenhouse effect is more important than carbon dioxide, but due to its low concentrations in the atmosphere about. 1.8 ppm overall effect is less, about a quarter of that of CO2. Since the beginning of the industrial revolution the concentration of methane in the atmosphere has increased by 149%.
