The process referred to as the greenhouse effect has lately been a very debatable issue and has been receiving a lot of criticism due to its association with the surging rates of global warming. Despite the criticism however, it is an otherwise very natural phenomenon and one that is also very essential to human existence.
Our atmosphere is made up of various gases which enable the light produced by the sun to reach the earth’s surface but also prevent reradiated heat energy from escaping back into the atmosphere. The sun produces the energy that sustains life on the planet earth.
About 30% of sunlight that hits the earth is deflected and scattered back into space by the outer atmosphere.
Infrared radiation reflects the rest of it back to the atmosphere in the form of slow-moving energy and atmospheric gases absorb it therefore slowing its escape from the atmosphere. This absorption creates a warm-air blanket that surrounds the earth and without which the planet would otherwise be all covered by ice and therefore be unable to sustain any life. But the greenhouse effect is changing and heat trapping gases have tremendously increased in the atmosphere such that there is less heat radiated back into outerspace.
This has resulted in global warming and subsequent alteration of the earth’s climate (Gonzalez & Sherer 374; Villegas 3).
The Greenhouse Effect
Naturally, the greenhouse effect results from a combination of gases which are found in the atmosphere namely carbon dioxide, nitrous oxides, methane, ozone and water vapor. Out of these gases, water vapor is the most abundant and is followed by carbon dioxide (CO2).
As a result of increased human activities on the earth’s surface such as industry, oil production, mining and agriculture, the levels of greenhouse gases have not only increased, but the activities lead to their increase have also added other gases like Chlorofluorocarbons (CFCs) which do not occur naturally.
CFCs and methane are said to be more effective trappers of atmospheric heat but lately, carbon dioxide has reached certain levels that have raised great concern for a number of reasons. Current levels of carbon dioxide in the atmosphere are quite high and have been rising tremendously as a result of various human especially the processing of fossil fuels. Rising levels of carbon dioxide production are said to contribute to 50% of all human-induced global warming.
Oil, natural gas and coal are mined from carbon-based tissues of animal and plant deposits that have been buried for centuries in the earth and which have been transformed by heat into fossil fuels. When these fuels are burned during processing, they release a considerable amount of carbon dioxide back into the atmosphere. Human activities and various industries also result in the release into the atmosphere of other greenhouse gases.
Rice paddies, landfills and livestock for example produce ample amounts of methane gas while various industrial processes release nitrous oxides into the atmosphere. Refrigeration and insulation processes contain chlorofluorocarbons and water vapor is released into the atmosphere from such processes as transpiration and evaporation. Deforestation has also been cited as a major cause of global warming because plants use carbon dioxide and release oxygen back into the atmosphere.
Excessive felling of trees for various human activities such as timber production, farming and urbanization means that as days go by, there are lesser and lesser trees to perform this natural but very essential function. An increased level of carbon dioxide and other greenhouse gases means that more infrared radiation is trapped and retained in the atmosphere resulting in higher temperatures on the earth’s surface as well as more air in the lower atmosphere. For these and other reasons, the greenhouse effect has become one of the factors thought to contribute to the high rate of global warming (West).
Global warming has various negative effects towards both human and other form of life on the earth.
As a result of rising temperatures, various scientists involved in studies about climatic change predict that long and severe droughts will become a common phenomenon in some part of the earth.
These severe droughts are the result of changing weather patterns in most parts of the world and have been blamed for such other catastrophes as wildfires like those frequently experienced in California, U.S.A in recent years.
Rising temperatures are also responsible for heat waves like those that hit Europe in the summer of 2003 causing the death of approximately 35,000 people. According to scientists, areas like Southeastern U.S.A may also be prone to more hurricanes and storms due to rising atmospheric temperatures. Excessive heat causes more evaporation which transfers heat back into the atmosphere and the heat in turn fuels the storms. Since the 1970s for example, there has been an increase in the number of tornadoes that have hit the U.S.A. These storms are usually very destructive leading to massive loss of property as well as displacement and loss of human life. (Science World).
Rising atmospheric temperatures have also been blamed for increased melting of ice deposits in such areas as Antarctica and Greenland. Scientists have reported that 87% of the 244 glaciers found in the Antarctic Circle have retreated and by June 2005, ice coverage in the sea had dropped 6% below average levels.
It is estimated that at the current rate of glacier melting, glaciers in the Glacier National Park in the U.S. will have disappeared completely by the year 2030. Since 1912, over 80% of the famed snow covering on Mt. Kilimanjaro in Africa has melted. When this melting ice flows into the sea, it leads to rising ocean levels. Experts estimate that ocean levels will have risen about 24 inches by the year 2100 raising fear of more frequent flooding in coastal areas due to frequent storms.
This flooding is potentially dangerous considering that two thirds of all cities in the world are located along coastlines and frequent flooding can be devastating for life in such urban centers (Villegas 5; Science World).
There are several measures that today’s society can take to help reduce the effects of a warmer earth. One of the most practical and probably equally effective measures is reforestation. The world has considerably lost most of its vegetation cover due to increased human activities. Trees absorb carbon dioxide and release back into it the oxygen that is necessary for sustaining life. Due to deforestation, trees on the earth’s surface are now too few to sustain this atmospheric exchange cycle. Re-planting of trees especially the drought resistant native species will help to absorb so much of the carbon dioxide that is released into the atmosphere.
And subsequently reduce the rising atmospheric temperatures. Another measure of reducing greenhouse emissions is saving on energy. Most of the greenhouse gases that are currently blamed for accelerating global warming are produced from motor vehicles, power plants, air conditioning systems and agricultural activities. Using less heat producing appliances and air conditioning apparatus as well as turning off light when they are not necessary can greatly help to save energy.
Saving appliances such as fluorescent tubes and energy saving bulbs can be used as they consume less energy. Overdependence on electricity and gasoline as sources of energy should be cut down and renewable sources of energy such as solar and wind power adopted to provide energy for various uses in the homes. To avoid overdependence on fossil fuels, people should adapt the use of public transport especially if travelling for short distances. Using personal cars less often reduces the number of vehicles on the roads, subsequently leading to less burning of fuel and less carbon dioxide released back into the atmosphere (Villegas 5-6).
Law enforcement and legislation actions around the globe can also be quite useful in helping to reduce the negative impact of greenhouse effect. Most of the world’s forests for example are managed through government ministries of management boards. Sustainable management of forest cover is a very important step towards reducing the alarming loss of approximately 13 million hectares of forests each year.
This will help in reducing the amount of greenhouse gases emitted into the atmosphere.
One of the main causes of deforestation is illegal logging and this has become a major problem in most countries of the world from the temperate forests of Europe to the tropics. Apart from reducing the forest cover, illegal logging also depresses wood prices and leads to massive loss of government revenue. Producer countries can therefore be supported through measures that will help to strengthen their governance and subsequently lead to efficient forest law enforcement.
Forest management can also be improved by not only introducing forest certification but also ensuring that the certification systems are credible and of good quality. Through international trade, policies can also be developed that will restrict purchase of forest products from certified companies only. Because biomass production has become very popular and wood chips are used in its production, ecological guidelines should be followed to ensure a balance on greenhouse gases (Hirschberger).
It is difficult to reverse or control such processes as industrialization, agriculture and urbanization. But responsible management of the environment we live as well as is quite possible and can be the only means of putting a check on global warming. Policies should be developed that will help to reduce overdependence on fossil fuel and adopt the use of low-polluting and renewable fuels like solar and wind-power; as well as maintain a green environment.
Unless urgent measures are taken, global warming may soon turn the world we live into a massive dry land.
Anonymous. Science World. “Warming Signs: Scientists warn about the Dangers of a Changing Climate.” New York: Vol.65, Iss.3; pg.18. Oct 6, 2008. July 31, 2009
Gonzalez, Joseph and Sherer Thomas E. The Complete Idiot’s Guide to Geography. Phoenix, AZ: Alpha Books, 2004.
Hirschberger, Peter. Forest Consulting. “Sustainable Forest Management.” July 31, 2009
West, Larry. About.com. “What is the Greenhouse Effect?: After 150 years of Industrialization, Climate Change is inevitable.” 2009. July 31, 2009 http://environment.about.com/od/globalwarming/a/greenhouse.ht.