The Sun is the primary source of energy for Earth. The energy reaches the planet in the form of sunlight. The light, which is an electro-magnetic wave, is mainly composed of infrared rays, visible light and ultraviolet rays. A major portion of the UV rays will be absorbed by the ozone layer around the Earth. The remaining rays will reach the planet along with the visible light and warm the Earth’s surface. These rays are of relatively smaller wavelength. The infrared rays, which have a greater wavelength, will be reflected by the hot surface of Earth.
These infrared rays, which have to escape the atmosphere, are but absorbed by some of the gases in the air. They then re-radiate these rays in different directions, mostly back to the Earth. These rays possess a large amount of energy and cause a rise in the atmospheric temperature. This phenomenon is much like what happens in a natural green house and hence is called the Greenhouse Effect.
The gases which have the ability to absorb the infrared rays are called greenhouse gases. A number of greenhouse gases are naturally found in atmosphere but others are the products of various human activities. Vapor, Carbon Dioxide, Methane, Nitrous Oxide, Ozone and Chlorofluorocarbons are the major greenhouse gases.
The idea of the greenhouse effect was put forward for the first time in 1824. A scientist named Joseph Fourier was the person who gave the first indications of the phenomenon. Another scientist, John Tyndall, took the studies further. He discovered how the heat radiations affect the gases and proved the phenomenon of greenhouse effect scientifically in 1859.
Carbon dioxide is one of the most dangerous among the greenhouse gases. It is a naturally occurring gas but the increasing industrial activities and deforestation are triggering an accelerated rise in the amount of the gas in the atmosphere. The share of carbon dioxide in greenhouse effect is between 9% and 26%.
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Although the Natural Greenhouse Effect is instrumental in preserving the biosphere, its growth leads to Global Warming, which is the result of Human Enhanced Greenhouse Effect. The phenomenon of Global Warming is one of the worst threats to nature now. The atmospheric temperature is on the rise every year. It is the cause of the melting of glaciers in Polar Regions and the rise in sea level, causing strong climatic changes. A number of low-level islands have disappeared and some are about to be drowned. The world nations have now understood the danger of global warming and begun to tackle the emission of carbon dioxide and other greenhouse gases.