Greenhouse Effect
Earth due to gravity on its surface retains air and seawater, and to set in motion the air and the sea in relation to the planet’s surface energy is needed as a primary source is the sun, which emits flow in all directions, visible light or near visible radiation in the areas of ultraviolet and infrared.
According to the approaches of Sadi Carnot on the operation of the steam engine, it is known that the transformation of thermal energy into mechanical energy can not be total. A heat engine requires a hot source of thermal energy supply and a cold source is received. In considering the Earth as a heat engine, the source that supplies the heat energy is the soil surface heated by solar radiation and the cold source is located in the upper layers of the atmosphere, cooled continuously by the loss of energy as infrared radiation emitted by the hot ground to outer space.
The Earth receives only a small amount of energy emitted by the Sun Sunlight is not used directly but as heat, therefore, it is necessary that the atmosphere transforms the thermal energy of solar radiation into mechanical energy wind. The source of heat to the atmosphere is heated the soil surface by sunlight which is then emitted as infrared radiation into space.
The greenhouse effect is one of the main factors that cause global warming of the Earth, due to the accumulation of so-called greenhouse gases CO2, H2O, O3, CH4 and CFCs in the atmosphere.
The French mathematician Jean B. J. Fourier argued that the Earth is a blue planet because of its atmosphere and that would be a black planet if he lacked it and that would freeze water if you have the mixture of gases that make up its atmosphere. In 1827 compared the influence of Earth’s atmosphere with greenhouse gases and said forming the Earth’s atmosphere serving as the glass walls of a greenhouse to keep warm.
The Irish physicist John Tyndall in 1859, found that neither oxygen or nitrogen produced greenhouse gases, which indicates that 99% of the components of the atmosphere do not produce greenhouse gases and that water, carbon dioxide and ozone it is produced. Tyndall realized that carbon dioxide absorbs a large amount of energy and its concentration varies naturally due to different phenomena, including organic fixation is carried out by the plants (see photosynthesis). Also that the decrease of the concentration of carbon dioxide in the atmosphere would cause the cooling of the planet and that it could be the explanation of ice ages on Earth.
The molecules of oxygen, nitrogen, water, carbon dioxide and ozone are nearly transparent to sunlight but the molecules of CO2, H2O, O3, CH4 and CFC’s are partially opaque to infrared radiation, ie, absorbed infrared radiation emitted by the soil that has been heated by sunlight.
When infrared radiation collides with molecules of CO2, H2O, O3, CH4 and CFC’s is absorbed by them. These molecules vibrate, move and emit energy in the form of invisible, infrared rays, causing the phenomenon known as the greenhouse effect, which keeps warm the atmosphere. Radiation bounce between the mixture of molecules that make up the atmosphere until they finally escape into outer space.
The term applied to greenhouse Earth relates to possible global warming due to the accumulation of greenhouse gases caused by human activity, especially since the industrial revolution by burning fossil fuels and production of new chemicals.
The Swedish chemist Svante A. Arrhenius, in 1896, argued that the concentration of carbon dioxide is increasing steadily due to the burning of coal, oil and wood, which causes the Earth’s average temperature is increasing. He noted that in case of doubling the concentration of carbon dioxide from the atmosphere, Earth’s average temperature would rise between 5 and 6 º C.
Although the greenhouse effect was known, during the first half of the twentieth century Earth researchers did not consider it a problem of global stability, as previously considered that the oceans could absorb the carbon dioxide forming calcium carbonate (CaCO3) would fall into the sea without causing any damage.
Infrared radiation is absorbed more by water vapor, carbon dioxide is followed and then the ozone, but of these three chemicals is carbon dioxide which produces more greenhouse gases because the man is increasing its concentration as a result of its activities.
It is considered that without the greenhouse effect produced by the natural carbon dioxide the temperature of the Earth would be about 20 degrees Celsius (- 20 ° C).
Scientists agree that carbon dioxide is involved in the greenhouse effect and its concentration is increasing (see chart), but disagree on two crucial aspects of the greenhouse effect: a) if it has already begun on global warming and 2) how global warming will increase (see global warming).
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Tags: greenhouse effect, retains air and seawater, surface, surface energy, ultraviolet and infrared