The Enhanced Greenhouse Effect

Hi Readers, This time Informasi Ahli will discuss about the enhanced greenhouse effect.
Many people regard the enhanced greenhouse effect as the most serious environmental threat to our present way of life on Earth. The greenhouse effect is the nature ‘trapping in’ of heat by gases such as carbon dioxide and methane in the atmosphere. By allowing short-wave radiation in, but trapping some of the long-wave radiation which is trying to get out, these gases act in a similar way to the glass in a greenhouse, hence the term greenhouse effect.
Without the greenhouse effect the average temperature on Earth would be about-170C and life on Earth as we know it would be impossible. The problem is that over the last few hundred years human activities have resulted in rising concentrations of many of the greenhouse gases. This has led to an increased or ‘enhaced’ greenhouse effect which, in turn, has led to an increased average global temperature. We now know that the mean global temperature has risen by 0.3-0.60C over the last one hundred years. Some scientists have estimated that if we do nothing to reduce greenhouse gas emissions, the average global temperature will rise by 0.30C every decade. Equally, it is important to note that some scientists do not agree with these claims. Others point out that any recent increase may simply be a natural fluctuation with few long-term consequences. However, temperature will not necessarily rise everywhere. Some areas of the worl may become cooler, and we simply do not know what overall effect this will have on regional and world climate. However, it is clear that the concentrations of the greenhouse gases are rising.
1. Carbon Dioxide (CO2)
Anthropogenic (human) realease of carbon dioxide contributes most to the enhanced greenhouse effect. All fossil fuels, such as coal and oil, contain carbon; burning them releases carbon dioxide. As world demand for energy encreases, so more fossil fuels are being burnt, hence COlevels are rising.
All green plants photosynthesise. They remove carbon dioxide from the atmosphere and use sunlight energy to convert it into carbohydrates. Thus they provide the food upon which all other living organisms directly or indirectly depend. Humans are destroying huge areas of natural vegetation, such as the tropical rainforests, hence global photosynthesis is declining, leaving mre carbon dioxide in the atmosphere. This problem is exacerbated if we burn destroyed vegetation, as combustion releases more CO2.
By analysing air bubbles trapped in ice, scientist have deduced how atmospheric carbon dioxide concetrations have changed over the last few thousand years. There have been many fluctuations, with low concentrations cerresponding with ice ages and high concentrations corresponding with warmer interglacial periods. However, it is important to note that most of the carbon in the bisphere is not in the atmosphere as carbon dioxide, but is locked up in vegetation, in soil, rocks and in sediment, and in the oceans. These are called carbon sinks and their relative importance is not clear. In other words, we simply do not know for sure where all the carbon is.
2. Chlorofluorocarbons (CFCs)
CFCs have been used as coolants in refrigerators, as propellants in aerosols and as expanders in expanded foam product. Their increasing concentration in the atmosphere over the last two decades reflects their wide usage. The Montreal Protocol (1987) has led to a huge decline in the production of CFCs but, unfortunately, CFCs that have already been released into the atmosphere will stay there for many decades. They have a long residence time.
3. Methane (CH4)
Methane is produced by anaerobic bacteria which live in marshes, landfill sites, rice paddies and in the guts of ruminants (for example, cattle, sheep, camels). A cow may release a phenomenal 200 litres of methane a day !. Atmospheric methane concentrations have risen as the ruminant population and the area given over to landfill have significantly increased. Leaking gas pipes and coal mines also release methane.
4. Nitrogen I oxide (N2O)
Nitrogen I oxide is released during fossil fuel combustion and from denitrifying bacteria which act on nitrates and nitrites. Increasing use of nitrate fertilisers and increasing cultivation of soils may be resulting in increasing concentrations of nitrogen I oxide.
5. Tropospheric Ozone (O3)
Tropospheric ozone (O3) is produced through a complex series of reactions involving pollutants from car exhausts, such as nitrogen I oxide, and hydrocarbons, which react with sunlight. Thus more vehicle use means a greater greenhouse effect.
Umpteen of informasi ahli about the enhanced greenhouse effect, hopefully writing informasi ahli about the enhanced greenhouse effect.

Source : Article about The Enhanced Greenhouse Effect :

– Kevin Byrne, 2001. Environmental Science Second Edition. Published by OUP Oxford : United Kingdom.
Picture Article The Enhanced Greenhouse Effect

Picture Article The Enhanced Greenhouse Effect

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