Global Warming, What and How?

Sunday, October 25, 2009
at 7:32 PM

It’s scorching hot today!” Do you find yourself, or other people around you, making this kind of statement frequently? If you do, well, you’re quite correct. Existing data shows that the earth’s average
temperature has been rising year after year. Besides the weather getting hotter, surely you are also  aware that there have been more occurrences of natural disasters and other uncontrollable natural phenomena lately, such as floods, hurricanes, gas explosions, and unpredictable rainfall. These are all nature’s way of telling us that our planet is being damaged and heading towards destruction.

They are directly related to the issue that has caught the world by storm, global warming. What is global warming? Briefly, it is the increase in the average temperature of the earth’s surface. The question is: why is it increasing?

The Cause of Global Warming 
For the past few decades, research has shown that the rising temperature of the earth is directly related to greenhouse gases produced by human activities. The United Nations has especially appointed the International Panel on Climate Change (IPCC), a team of researchers, to monitor the causes and consequences of global warming. Every few years, thousands of the world’s foremost experts and researchers meet to discuss the latest global warming-related findings, and draw conclusions based on the most up-to-date reports and discoveries, and approve of solutions to existing problems. One of their earliest discoveries is that several types of greenhouse gases are directly responsible for the higher temperatures we are experiencing, and that humans are the largest contributor to the production of these gases. Most greenhouse gases are generated from the burning of fossil fuels in motor vehicles, modern factories, farms, and electrical generators.

What are Greenhouse Gases?
The earth’s atmosphere consists of various types of gases, each with its own unique function. The group of gases that help maintain the warmth of the earth’s surface are known as “greenhouse gases,” so called because the way they work on the earth’s atmosphere is similar to the way a greenhouse traps solar radiation to maintain warmth, enabling the growth of plants inside. Refer to Illustration 1 to see how greenhouse gases work. These gases are necessary for our survival on this planet. Without  greenhouse gases, there would be no atmospheric layer to trap solar radiation and the earth would be too cold to inhabit. By comparison, Planet Mars has a thin layer of atmosphere and no greenhouse effect: its average temperature is -32 degrees
Centigrade.
The largest single contributor to global warming today is carbon dioxide (CO2), methane (CH4) produced by agriculture and livestock (particularly from the digestive system of farm animals), nitrogen oxide (NO) from fertilizers, and gases used in refrigerators and air conditioners (CFC). The destruction of forests that should function as storage for CO2 exacerbates the situation because dead trees release their CO2 contents into the atmosphere. Every greenhouse gas has a unique global warming effect. Some gases produce warming effects that are even worse than CO2. For example, a methane molecule produces warming effects 23 times greater than a CO2 molecule. A NO molecule can even produce warming  effects 300 times greater compared to a CO2 molecule. Some other gases, such as cholorofluorocarbon (CFC),can produce up to thousands of times more heat than CO2. Fortunately, the use of CFC has been banned in many countries because it has long been known to be the main cause of the destruction of the ozone layer



For an interactive, animated presentation of the above illustration, log on to:
http://science.nationalgeographic.com/science/environment/global-warming/gw-overview-interactive.html?nav=FEATURES

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