GLOBAL CLIMATE CHANGE CAUSES (Global Warming and Greenhouse Effect)

The energy received by Earth from the Sun, must be balanced by the radiation emitted from the Earth's surface. In the absence of any atmosphere, the surface temperature would be about -18 ° C. This is known as the effective temperature of terrestrial radiation. In fact, the land surface temperature is approximately 15 ° C.

The Greenhouse Effect

The reason for the discrepancy in temperature is that the atmosphere is almost transparent to shortwave radiation, but absorbs most of the longwave radiation emitted by the Earth's surface. Various atmospheric constituents such as water vapor, carbon dioxide, have molecular vibrational frequencies in the spectral range of the terrestrial radiation emitted. These greenhouse gases absorb and re-radiation of long wave, returning to the earth's surface, causing the temperature increase, a phenomenon called the Greenhouse Effect (GCCIP, 1997).

Diagram of the Greenhouse Effect (Miller, 1991)

The glass of a greenhouse-like atmosphere is transparent to sunlight, but opaque to terrestrial radiation, but confines the air to its interior, without the hot air can escape (McIlveen, 1986, Anderson et al, 1987). So in reality, the process involved is different and the name is quite deceptive, the interior of a greenhouse stays warm because the glass inhibits heat loss through convection into the air that surrounds it. Therefore, the atmospheric phenomenon is based on a process different from a greenhouse, but the term has become popular, therefore, that there is no way to establish a more accurate term.

One of the many threats to the systems of life support, a direct result of increased use of resources. The burning of fossil fuels and felling and burning of forests releases carbon dioxide. The accumulation of this gas, along with others, traps solar radiation near the Earth's surface, causing global warming. This could in the next 45 years, raising sea levels enough to inundate low-lying areas in coastal cities and river deltas. Also drastically alter the international agricultural production and exchange systems (WMO, 1986).

One outcome of the Greenhouse Effect, is to maintain a concentration of water vapor in the lower troposphere much higher than would be possible at low temperatures that exist in the absence of the phenomenon. There is speculation that on Venus, volcanic temperatures rose to the point that we could not form the oceans, and the resulting steam produced a greenhouse effect, further exacerbated by the release of carbon dioxide in carbonated rocks, ending up in surface temperatures over 400 ° C (Anderson et al, 1987).

Summary table of Greenhouse Gases

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