| | | Green House Effect

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Occupants of the earth depend on the Sun for energy to sustain life. About one third of the sunlight that is focused towards the earth gets deflected by the outer atmosphere and gets scattered back into space. The rest of the light reaches the earth’s surface and is again reflected upward as a form of slow moving energy called infrared radiation. Air currents carry the infrared radiation aloft and get absorbed by “greenhouse gases” i.e., water vapor, carbon dioxide, methane and ozone, slowing down the escape of the infrared rays from the atmosphere. Though only about 1% of the earth’s atmosphere is made up of greenhouse gases, our climate is regulated by them, by trapping heat and holding it like a warm air blanket around the planet. Scientists call this phenomenon the “greenhouse effect.” According to scientists, without the “greenhouse effect” the average temperature on earth would be colder by about 30 degrees Celsius. At that temperature, life on this planet would become unsustainable.

The Human Contribution to the Green House Effect

Life on this earth would become unsustainable without the greenhouse effect. It is the protective blanket or insulation provided to mankind, by the creator. But, human activities tend to either distort or accelerate the natural process by infusing more green house gases into the atmosphere than are necessary to keep the planet warm at an ideal temperature.

How Does That Happen?

The gasoline for automobiles, natural gas, coal and oil when burnt for any purpose, raises the level of carbon dioxide in the atmosphere. The Increase in levels of methane and nitrous oxide due to certain farming practices and long lasting industrial gases make a significant contribution to the greenhouse effect and "global warming” presently under way.

Trees use carbon dioxide and give off oxygen, which helps maintain the optimal balance of gases in the atmosphere. With more and more trees being cut down for human use in various forms, the critical function performed by the trees also diminishes quantitatively. With the kind of population growth we are witnessing, more and more people use fossil fuels for transportation, manufacturing, heating, and so on and the level of greenhouse gases sent up into the atmosphere increases exponentially.

Finally, when more and more greenhouse gases are sent into the atmosphere, more infrared radiation is trapped and held, leading to higher temperatures on the surface of the earth and in the lower atmosphere.

Rapid Increase in Average Global Temperature

During the whole of the 20th century, the average global temperature increased by approximately 0.6 degree Celsius (little over 1 degree Fahrenheit). Using computer aided data, scientists estimate that by the end of the year 2100, the average global temperature will increase by 1.4 degrees to 5.8 degrees Celsius (about 2.5 degrees to 10.5 degrees Fahrenheit). Changes occurring at this speed do not portend well for mankind.

Effects of Global Warming and the Greenhouse Effect

Scientists opine that even a small increase in global temperature can cause distinct changes in climate and weather and affect cloud cover, wind patterns, precipitation, severity and frequency of storms and duration of seasons.

Sea levels would rise as a consequence of rising temperature and result in a reduced supply of fresh water. This would be hindered by floods along the coastlines worldwide and salt water would reach inland. Several endangered species could become extinct since the rising temperatures affect their habitat. Millions of people, particularly the poor living in precarious locations or dependent on land for subsistence would be affected. Certain types of diseases like malaria would become more prevalent since the carrier insects or animals would have an expanded range due to warmer conditions.

Every 20 years, the level of carbon dioxide in the atmosphere is increasing by over 10 percent and carbon dioxide constitutes 60 percent of the enhanced greenhouse effect. If carbon dioxide emissions continue to grow at current levels, the level of gas in the atmosphere can grow many-fold. Not a very welcome thought.

You Have Company, If You are an Optimist

The picture portrayed above, are the views held by a majority of the scientific world, but there are equally authentic sources which claim that all the noise being made on the “green house effect” are not necessary. Some time back, the United Nations reported that humans are very likely to be blamed for global warming because of the way they use fossil fuels. But there are other climate experts who differ and state that there is not enough scientific evidence to prove this theory. They hold the view that global warming can be caused by an increase in solar activity like a massive eruption. A professor from the University of Ottawa has claimed that a rise in carbon dioxide levels happened some 800 years before warmer periods of the Earth’s history. Yet another salvo from those who rubbish the theory is that after the Second World War, inspite of the huge surge in carbon dioxide emissions, global temperatures in fact, dropped for four decades after 1940.

Not Everybody Agrees

Though this is the wide spread concern, there are some who do not subscribe to the fears expressed by the global community. A well respected American professor and climatologist holds the view that there is no reason to be overtly concerned. He has come to this view after analyzing millions of measurements from weather satellites to find a global temperature trend. His research did not show any global warming in the satellite data, and therefore believes that the global warming predictions, particularly those high levels, are factually incorrect.

Conclusion

In conclusion, there is plenty that is being said and written about concerns of global warming and the “greenhouse effect”. Yet, to strike a common thread between these differing groups and understand whether the threat is indeed as gargantuan as it is portrayed to be, only time will tell. == Sources ==

http://searchwarp.com/swa7370.htm

http://environment.about.com/od/globalwarming/a/greenhouse.htm