By Eleanor B. Jhonsons
Earth, the only planet in our solar system or as far as evidence indicates the only planet in the whole Universe that supports life, was not like as we see it now since its beginning. Earth has been able to give a safe home to life because of its unique place in the solar system; it’s neither too close to the Sun nor too far away. As Earth is situated away from the Sun preventing it from being a hell of a warm place, there was the possibility that it may have been freezing cold for life to form and flourish here. But thanks to the greenhouse gases present in Earth’s atmosphere that play their role in keeping it warm enough.
Greenhouse gases are those gases residing in Earth’s atmosphere that absorb and emit radiation and thus, keep Earth warmer. The ‘Greenhouse Effect’ is the natural process through which these atmospheric constituents absorb sunlight. Sun, the only star in our Solar System, emits light that reaches Earth’s atmosphere. The greenhouse gases in the atmosphere absorb the long wave radiation emitted by Sun which warms the atmosphere and these long wave radiations are emitted both upward and downward; the downward emission of radiation by atmosphere is called the ‘Greenhouse Effect’.
The greenhouse gases present in Earth’s atmosphere are water vapor, carbon dioxide, methane and ozone. Water vapor is the most abundant gas and plays the lead role in warming earth causing 36-70% of ‘greenhouse effect’. Carbon dioxide contributes 9-26%, methane 4-9% while ozone’s share is about 3-7%. Some of the other greenhouse gases present in much smaller quantities are sulfur hexafluoride, hydro fluorocarbons, chlorofluorocarbons, per fluorocarbons and nitrous oxide. Two of the major components of Earth’s atmosphere, oxygen and nitrogen are thankfully not greenhouse gases otherwise earth’s atmosphere would have been far warmer than it is now.
Although, these greenhouse gases have been playing a major role in providing life on Earth the perfect temperature to survive, since the Industrial Revolution human activities have caused increase in quantity of green house gases in the atmosphere. More greenhouse gases will trap more and more heat from Sun giving rise to the Global Warming phenomenon.
January 19th, 2009
By Raguraman Gurusamy
The gases that absorb radiation are called greenhouse gases. The greenhouse gases include the gases such as carbon dioxide, methane, nitrous oxide, ozone, or water vapor that contribute to the warming of the atmosphere of the Earth by reflecting radiation from the surface of the Earth. They keep the Earth warm. They naturally exist in the atmosphere, heating the atmosphere of the Earth by trapping energy that originally comes from the Sun. Due to this, the temperature of the Earth increases. This is known as the greenhouse effect. The greenhouse gases play the vital role in raising the temperature of the Earth. If the greenhouse gases are not there on the surface of the Earth, the Earth would be as cold as the surface of the Moon. The temperature would be around -18 degree Celsius. Actually, the characteristic surface temperature of the Earth is around 15 degree Celsius. It is now worried that the warming effects are being lamentably increased, inducing climate changes and melting of polar icecaps.
All the countries are keenly watching the warming effect. Almost all the countries are taking effort to measure the climatic changes taking places in the globe; however, the measurement is clearly showing that the global climate is keep on changing. In the past 100 years, the atmosphere of the Earth has warmed up by about half a degree Celsius. In addition, during this time human beings have also been released extra greenhouse gases. These gases have been produced as a result of burning the fossil fuels like coal, gas, and oil.
It is evident that the artificial emissions of greenhouse gases, by the activity of increased use of fossil fuels, are accountable for some of the warming of the global climate during the 20th century. The additional greenhouse gases present in the atmosphere absorb more energy and consequently increase the greenhouse effect. Due to this, the global temperature can raise further.
Besides by burning the fossil fuels, the greenhouse gases have also produced by the exhausts of motor vehicles. The destruction of rain forests is also responsible for the release of carbon dioxide, which in turn causes global warming. There are also many other natural ways by which the climate can be changed. The gases released from active volcanoes mix with the water vapor present in the air to create aerosols, and cool the atmosphere. The changes in the energy of the Sun and the flow of the ocean also affect the climate of the Earth. If the Earth keeps on to warm as predicted by the climate models, the temperature of the surface of the Earth may be three degree Celsius warmer than the current temperature by the year 2100. Due to this sudden change in the temperature, many ecosystems would get affected; which in turn affects many species of animals and plants.
January 19th, 2009