Global warming refers to the overall rise in the average temperature of the Earth’s atmosphere. The main source of global warming is the increase of greenhouse gases such as carbon dioxide, oxides of nitrogen, methane and chlorofluorocarbon in the atmosphere.

The Concentration of greenhouses gases

The above table shows the concentration of gases in the atmosphere.

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When the sun’s rays shine on the Earth, part of the light energy is absorbed as heat by the Earth’s surface while the rest is reflected back into the atmosphere. Greenhouse gases act like the glass surface of a greenhouse and reflect the heat back to the earth, resulting in an increase in temperature.

The Greenhouse Effect

When sunlight enters the atmosphere, some of the solar radiation is reflected back into space but most of it is absorbed by the Earth’s surface to heat up land and sea surfaces. As the Earth is heated up, heat in the form of infrared radiation is reflected back into space. However, most of the heat does not escape as it is trapped in the atmosphere by greenhouse gases which in turn radiate infrared rays back to Earth.

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This heats up the Earth which would otherwise to be too cold for living organisms. This phenomenon is called the greenhouse effect. The greenhouse effects is linked to global warming because when more greenhouse gases are produced, more heat is trapped, resulting in an increase of Earth’s temperature. Ways to reduce greenhouse gases and global warming: a) reducing the burning of fossil fuels b) using alternative sources of energy such as hydro, wind and solar energy c) reducing deforestation d) replanting forest trees.

The importance of the Ozone Layer

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The ozone molecule (03) is made up of three atoms of oxygen. The ozone layer is a natural layer of ozone gas in the stratosphere about 15 to 30 kilometers from Earth’s surface. The ozone layer absorbs about 95% to 99% of ultraviolet (UV) radiation and protects all living organisms on Earth from the harmful effects of this radiation. Sunburn is due to UV rays that penetrate through the ozone layer. These rays are absorbed by plant and animal tissues which damage protein and DNA molecules.

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Chemicals that Damage the Ozone Layer

The Thinning of the ozone layer is due to the increasing levels of chlorofluorocarbons in the atmosphere. In the stratosphere, CFCs are broken down by UV rays, thus releasing active chlorine radicals. These free chlorine radicals break down ozone molecules of ozone molecules.

It is the chlorine atom which is produced by the splitting of CFC molecules by ultraviolet rays. This leads to a series of chemical reactions and the breakdown of ozone molecules.

Effects of the Thinning of the Ozone Layer on Living Thing

On humans: a) mutation b) cataracts c) skin cancer d) sunburn e) affects the human immune system thus reducing the ability of the body to resist infections diseases. On plants and animals: a) reduces crop yields and reduces their nutrient content b) destroys cell membranes of leaves and reduces the amount of chlorophyll, thus affecting the rate of photosynthesis c) kills aquatic organisms, phytoplankton (which supply proteins) and aquatic plants (producers in food chains).

Effects of Environmental Pollution

Human activities associated with rapid development seriously upset the balance of nature, for example an increase or decrease in the population of animals and the loss of their habitats. Such activities cause harmful effects on several aspects such as: a0 human health b) habitats and nature c) the extinction of species d) the loss of economics resources.

a) Harmful effects on human health

i) A clean and unpolluted environment ensures good health for human.

ii) Air pollution causes diseases such as bronchitis and asthma, the inflammation of the respiratory tract and weakens the immune system, thus resulting in the body being easily attacked by bacteria and viruses.

iii) Effluent from heavy industries is the main source of heavy metal (lead and mercury) pollution which can cause damage and death. The heavy metal cadmium causes damage to the kidneys, lungs and the heart.

iv) Radioactive wastes can cause cancer and leukemia.

b) Destruction of Habitats and Nature

i) Water containing toxic substances and chemical fertilizers kill aquatic organisms. Acidic water from mines contain large amounts of sulphide and iron which react with oxygen in the air. This pollutes the water thus destroying the habitat of aquatic organisms. Eutrophication also causes the death of aquatic organisms.

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ii) Gases (sulphur dioxide and oxides of nitrogen) released from factories result in the formation of acid rain. Acid rain corrodes the stems and leaves of plants. Rainwater causes the leaching of minerals in the soil which affects the absorption of nutrients by plant roots.

iii) Acid rain causes the death of trees and indirectly the loss of habitats for organisms which depend on trees for food and shelter.

iv) Disturbances to living organisms on land and in water affect the food webs in the respective ecosystems.

c) The extinction of species

i) The population of living organisms that cannot adapt to changes in the environment decreases and finally becomes extinct. For example, a decrease in frog and crocodile population is due to spraying of chemicals made from plastics and pesticides. These chemicals affect the secretion of hormones and the reproduction processes in these animals.

ii) Deforestation carried out by humans destroys the habitats and affects the lives of many wildlife species.

iii) Coral reefs are breeding grounds for many aquatic species. Destruction of corals reef due to oil spills, sewage disposal and effluent from factories may result in the extinction of many aquatic species.

iv) Noise pollution caused by ships in the oceans, oil drills and fishing activities which involve the use of explosives disturb the communication of whales and other aquatic organisms. It also affects the whales’ habitat, their health and reduces their ability to reproduce which leads to a decrease in the whale population.

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d) Loss of economic resources

i) Air pollution causes the formation of acid rain which destroys forest trees. This results in a loss of economic resources from forests which include timber, rattan as well and minerals.

ii) Water pollution causes a decrease in aquatic plants and organisms which lead to lost revenues.

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Over the past 40 years, the Earth’s average temperature has risen by 0.2 to 0.3°C. In Malaysia, the temperature is rising by about 0.18°C every decade.

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A greenhouse is built from glass to grow plants in cold countries during winter. Sunlight enters through the glass roof and heats up the soil, plants and floor of the greenhouse. The heat generated cannot escape but is trapped inside the greenhouse to keep the plants warm. Earth is like a big greenhouse where greenhouse gasses behave like glass panes which trap heat and heat up the surroundings.

Nitrogen oxide decomposes into nitric oxide and free oxygen radicals in the presence of sunlight. The free oxygen radicals combine with oxygen molecules, producing low level ozone which acts as a greenhouse gas. Ozone gas causes smog and imitation to the eyes, throat and lungs.

In the middle of the 20^th century, scientists such as the Nobel Peace Prize Laureate Norman Borlaug experimented with breeding of crops and came up with high-yield strains of rice such as IR8 and IR36 (Huke). These strains were more resistant to damage than traditional rice, had higher yields, and had shorter growing seasons. From there, other scientists bred strains that could utilize fertilizers more effectively, and strains that could grow with less water. Shortly afterwards, scientists began to experiment with gene modification and introducing genes of one organism to other unrelated organisms. This step increased the potentials of crop strains immensely. However, it has also attracted widespread opposition for various reasons.

Most usage of GM crops occurs in the US, Argentina, and Brazil. The US grows 54 percent of the world’s genetically modified foods; Argentina grows 18%, and Brazil grows 11% (Raney). Growing GM crops has generally had positive effects on the profits of farmers. China and South Africa have had significantly large increases in revenues. Despite these benefits, many people in every country oppose the use of genetically modified foods (Raney). Several African countries and Venezuela have partially or fully banned importation or usage of GMOs. Other countries have required all retail outlets that sell genetically modified food to label it as such. These countries dislike genetically modified foods for many similar reasons.

Proponents of genetically modified crops claim that they could solve or at least help with the problem of world hunger, since they can have extra nutrients, give higher yields, and be resistant to insects and adverse weather. GMOs could also be used to deliver vaccines to people. An example of a genetically modified food is “golden rice”. Two scientists named Potrykus and Beyer created “golden rice” which had an increased amount of beta-carotene, a building block for vitamin A (Nash). This would help prevent blindness caused by vitamin A deficiency, and also would help feed hungry people. Other examples of these modified organisms are “bananas that produce human vaccines against infectious diseases such as hepatitis B; fish that mature more quickly; cows that are resistant to mad cow disease; fruit and nut trees that yield years earlier, and plants that produce new plastics with unique properties (Human Genome Project Organization).”

Opponents of GMOs, on the other hand, have numerous arguments of their own. For example, a study by Rebecca Goldburg has shown that some insect resistant crops that produce their own pesticides can unintentionally also kill other organisms, such as the monarch butterfly, reducing biodiversity (Klee). These same crops can also cause “the evolution of superbugs with a high tolerance for toxic pesticides (Perian). On a similar note, pollen from genetically modified crops could cross pollinate with wild plants and create “superweeds”. For example, there are concerns that genetically modified canola in Australia could become a weed that grows rampantly across the countryside because it is so prolific and because it is very resistant to being killed (Hedley). Others fear that GM foods could be dangerous to humans. Because genes from different organisms are spliced together to form a new version of a crop, many worry that GM crops could have allergens that would cause allergic reactions (Perian). Another position is that large agribusinesses would try to use genetically modified crops to put small time farmers out of business. This would increase the disparity between the wealth of the rich and the poor. Ethical issues also arise because some believe that creating GMOs is meddling with nature. Finally, antagonists of genetically modified foods state that there could be other random, unforeseen consequences of GMOs (Human Genome Project).

I personally support the use of genetically modified foods. Many of their arguments aren’t so powerful when put into perspective. Many GMO critics believe that we shouldn’t use genetically modified foods because we don’t know all of the possible consequences of using them; they often cite the pesticide DDT that harmed wildlife and contaminated. But it is obviously impossible to test every single problem that could possibly occur for anything. The positions of people who object based on this argument are reminiscent of the Luddite ideas. The Luddites were a social movement of British artisans in the 1800s (Ryder). They opposed the industrialization of Britain, because they feared change and thought that there would be many unforeseen negative consequences. As it turned out, there were many negative consequences, yet there are few that would say that they would rather live in an unindustrialized world. As to the reference to DDT, even that is not such a strong argument when put in perspective. Because DDT was harmful to animals and to their environment, many people overlook the benefits that it had. First, DDT was a very effective herbicide, killing pests very successfully. By doing so, it dropped the malaria rate greatly. According to Radley Balko:

… in the 1940s, malaria afflicted over 200 million people worldwide. In 1930, 1,740 per million died of the disease. But by 1950 after widespread use of DDT began, that number had dropped to 480. By 1970, it was down do just 160. And since the ban on DDT went into effect in 1972, Goklany notes, malaria has again asserted itself in the developing world.

This shows that even though there may be problems with a new product or invention, there could be unanticipated benefits as well as problems.

Various other groups claim that GM foods could be detrimental to human health and cause unforeseen side effects. However, many groups have already testified to the safety of the biotechnology, including the US Depatment of Agriculture, the Food and Drug Administration, the Environmental Protection Agency, the American Medical Association, the National Academy of Sciences, and the World Health Organization. In addition, 70% of the processed foods in the United States contain some genetically modified organism, yet there have been no major public health incidents that were traceable to GMOs (Balko). This in itself shows that GM foods do not cause any real problems in humans.

Then there are those that claim that large agribusinesses will take over the world agriculture economy and drive small-scale farmers out of the market. However, the seeds could easily be given to the small-scale farmers to help them grow more food. And the takeover of the world agriculture by large corporate businesses cannot really be linked to the use of genetically modified foods. Most likely, even if genetically modified foods had not been developed, large businesses would still try to control the market and to drive the small-scale farmers out of businesses. If the seeds of GM crops were given to poor farmers, they would be able to feed themselves and the local area.

One problem aside from the obvious one of world hunger that GM foods would help is deforestation. Since farmers around the world are running out of land to grow crops in, they are clear cutting large areas of forest to grow their crops. GM foods would be able to get higher yields in the first place, so that there would be less of a need for new farmland. This would help preserve some biological diversity to offset some of the problems of reduction of biodiversity.

Many people refuse genetically modified foods because of common misconceptions. A few think that eating GM foods will cause them to mutate, though this misconception has generally been cleared up. Others think of genetically engineered as being synonymous to radioactive. An example of a misconception is when Victor Campos from the Humboldt Center, a Nicaraguan environ mental group, said that “It is well known that …food companies in the US and Europe do not use genetically modified products. Nevertheless, our highly vulnerable condition has been used as an opportunity to send products that children in developed countries do not consume (CorpWatch).” I do not know what kind of depraved garbage this imbecile is besotted with, but it is widely known that the US produces and consumes a gargantuan amount of genetically modified foods, and that there have not been any major health issues traced to them. There has only been one minor potential health issue that has been found with genetically engineered crops. Aventis, the company that manufactured StarLink corn, was not able to prove that one of its proteins was not an allergen, so the Environmental Protection Agency forced them to take tons of the corn off of the market (CorpWatch). Even so, there had not been any people that had reacted badly to the corn.

Finally, there is the obvious fact that the people who decide to reject genetically modified food aid given to poor countries are not the people that starve as a consequence. The leaders of countries present themselves as eco-friendly and righteously protective of their people, but do so at the expense of their people. When there are millions of their people are starving, the bureaucrats should not be allowed to play politics while the people suffer and die.

The one thing that I agree with opponents of GM foods about is that large corporate agricultural businesses are becoming too greedy and powerful. They are suing small-scale farmers indiscriminately if they happen to be growing GM foods without permission (Nash). They are also trying to include a “terminator” gene that would “render a crop’s seeds sterile,” forcing buyers to constantly buy the seed from the big companies. This practice should be stopped to help the needy.

In conclusion, GMOs have a variety of benefits and setbacks. A decision as to whether or not they should be allowed would have repercussions around the world. I believe that the benefits outweigh the negative aspects, and that GMOs would help solve problems around the world.