Global Warming is an issue that concerns almost everybody worldwide: it is the primary cause for the erratic and sometimes devastating weather that is experienced around the world. Global warming is causing the rise in sea level which in turn causes the flooding of coastal areas and areas with low elevation.
Is global warming really happening today? Scientists with the United Nations Environmental Program (UNEP) believe it is so. In fact, they feel that records from past climates support the case for global warming.
It is indisputable that there has been a rise in the concentration of greenhouse gases (GHG) in the atmosphere during the last century, which scientists think may be one of the causes of global warming. The climate change however is not a direct result of the rise in greenhouse gases, but on natural “climate feedback” mechanisms, particularly those due to clouds, water vapor, and snow cover (Bellamy & Gifford, 2000).
Each of these may change in response to global warming and may therefore act either to enhance or suppress any temperature rise. Past climates have left records in ice and ocean sediment cores which provide some of the best available evidence. The information gathered from the ice which has been trapped for thousands of years suggests that temperatures have varied closely with GHG concentration for most of the past 100,000 years.
However, scientists are not certain whether the GHG’s caused the temperature to change or was it the other way around. They believe that the factors affecting the earth’s “climate controlling” operate on very different time-scales. The slower acting factors are the earth’s orbital movements around the sun and the expansion and retreat of polar ice caps. The faster acting ones are atmospheric dust; changes in ocean circulation; feedback due to water vapor, clouds, and snow (Cairncross, 2002).
This study scrutinizes the effect of global warming worldwide and do the humans are the reasons of causing global warming or if its just a natural process that the earth goes through.
A. Global Warming and doomsday
Will global warming spell doom for our world? Scientists believe this to be so. “Much depends on what actions we take now and in the coming years.” Meteorologist Jagadish Shukla of the University of Maryland found out that deforestation would cause rainfall in the Amazon River to decline by more than 26 percent from the current 2.5 m. to about 1.8 m. a year.
At the same time, the burning of fossil fuels, particularly coal and oil, produces sulfur dioxide and nitrogen oxides which are hazardous to the atmosphere. Findings show that a single smokestack may produce as much as 500 tons of sulfur dioxide a day. When these gases combine with oxygen and moisture, sulfuric acid and nitric acid is formed. The rain will carry the acids to the ground (acid rain) which may cause the depletion of calcium and magnesium in the soil, elements needed by plants for the formation of chlorophyll and wood, or it may cause the release of aluminum in the soil, which are poisonous and can kill the roots of trees (Carwardine, 2000).
Dr. Nafis Sadik, executive director of the UN Population Fund, stressed the need to slow population. “These increasing numbers are eating away the Earth itself,” wrote Sadik. “The combination of fast population growth in poor countries has begun to make permanent changes in the environment.”
The UNPF predicted that if the number continues to grow at the same rate, the world’s population will reach 6.2 billion by the end of the 2000—the equivalent of adding another China. This means, Sadik said, that more people increased pressure on already stressed lands, forests and water supplies. Other sources of climatic change were attributed to some forms of gases such as nitrous oxide, methane and chlorofluorocarbons (CFC’s) (Cronin, 2001).
Nitrous oxide or “laughing gas’ is a colorless gas with a sweet taste and odor that is used as an anaesthetic in minor surgery that H2O is responsible for about 6 percent of the human contributes to greenhouse warming. Methane or “cow gas,” on the other hand, makes up about 18 percent of human contributions to greenhouse effect. Cattle, sheep, goats, and other cud-chewing animals give off methane, in burps and flatulence as they digest. CFCs was discovered by Thomas Widgley Jr., a chemist working at the Frigidaire Division of General Motors, used as coolants in refrigerators and air conditioners and aerosol propellants in spray cans, medical sterilizers, cleaning solvents for electronic components and raw materials for making plastic foams such as coffee cups. CFCs are estimated to account for 14 percent of global warming. Experts said that what is happening right now is not a matter of adding a few degrees to the average temperature of a community. A rise of this magnitude may cause life, for without the environment, creatures on earth cannot survive (Davidson, 1999).
A. Ozone Slayers
It is hailed as the greatest success yet in the defense of Planet Earth. Many Presidents and Prime Ministers present themselves as the saviors of the ozone layer—the leaders who rescued the fragile atmospheric shield that protects all living things from the sun’s dangerous ultraviolet rays. This airbrushed view history starts in 1985, when scientists realized that an ozone hole had opened over the South Pole—the result of an atmospheric assault by man-made chemicals called chlorofluorocarbons, which are commonly used in refrigerators and air conditioners. Soon after this disturbing surprise, the diplomats of the world were at the negotiating table. By 1987, they had reached a preliminary agreement to phase out production of CFCs, and by 1990, they had set 2000 as the target year for a total ban. Now most countries expect to beat that deadline by many years because substitutes for CFCs are coming on line more rapidly than expected. The central player in the drama—the unwitting villain turned hero—was Du Pont, the American chemical company that invented CFCs, dominated global production and eventually led the way in developing substitutes (Durrell, 1999).
There is only one problem with this fabled success story: the rescuers may have arrived too late. No matter how quickly manufacturers halt the production of CFCs, billions of kilos of the chemicals already produced will continue to seep into the atmosphere and rise inexorably to attack the ozone layer. Worse, measurement after measurement since the mid-1980s has shown that ozone loss has been greater and more rapid than scientists predicted. Researchers disclosed new satellite readings that in 2002 the average concentration of ozone in the upper atmosphere around the globe was 2% to 3% lower than any previous reading and 1.5% below what computer models predicted. That news came just a week after the World Meteorological Organization reported that ozone levels over some northern parts of Europe and Canada feel as much as 20% this winter (Environment Matters: Industry’s Guide to the Issues, the Challenges and the Solutions. London: World Petrochemicals Analysis, 1999).
The amount of CFCs in the atmosphere will keep rising until at least the year 2000; after that in may slowly fall, but ozone destruction will continue or several decades in the 21st century. Some optimistic scientists predict that the impact on the heavily populated latitudes will be tolerable: at worst, a 6% ozone loss during the summer months, which could cause a 12% increase in ultraviolet radiation. Given the volatile and poorly understood chemistry of the upper atmosphere, no one can predict exactly how severe the ozone depletion will be. Even a modest rise in the level of UV radiation could increase the risk of getting skin cancer or cataracts, damage crops and other plant life, and possibly affect climate patterns (Jenner & Smith, 1999).
Furthermore, ozone is an unstable oxygen that occurs naturally in the atmosphere (also called isothermal region), the upper portion of the atmosphere above 7 miles where clouds are rare. The ozone layer absorbs the dangerous ultraviolet-B (UV-B) rays while it allows the needed safe light to pass through. Though easily broken down by other gases in the stratosphere, it is constantly being repaired by the sun’s rays. However, man is destroying the ozone layer which serves as a protective umbrella against the sun’s harmful rays. In fact, the ozone layer is destroyed faster than the sun’s rays can produce it. It is being destroyed by industrial gases like CFCs (Johnston, 2000).
CFCs were invented in 1930 but were discovered hazardous in 1974—only after 44 years of use. CFCs, which are found everywhere, are used in foamed plastic production (insulators, cups, fast-food containers), spray propellants, coolants (refrigerators, air-conditioners) and solvent cleaner (electronic equipment).It is dismaying to know that ozone depletion can be found in the south (Antarctica) and north (Greenland) poles. According to British scientist Joe Farman, 40 percent of ozone depletion can be found in the South Pole. At the South Pole is a huge vortex with clouds composed of tiny ice [articles, giving chlorine millions of tiny spaces through which it can perform its deadly dance with ozone even faster (Simpson, 2000).
Both holes at the poles are seasonal, opening and closing each year. In the northern hemisphere, a more populous region, ozone depletion rate is between three percent and seven percent for 17 years, as compared previously to only three percent for100 years.
What are the effects of Ultraviolet-B rays to human beings and the ecosystem in general? To humans, they can cause skin cancer and cataract as mentioned earlier and damage the immune system. To the ecosystem, they can kill planktons (basic element of the ocean food chain), destroy plant life and crops and change global wind and weather patterns.
In 1978, Canada, Sweden, the United States and other countries banned the use of CFCs in aerosols. However, other uses of CFCs were found, effecting an increase in its production. The US still uses one-fourth of the world’s annual supply of CFCs (Turner, 2000).
However, in September 1987, 24 nations cooperated for the first time to solve this environmental problem and passed the Montreal Protocol. The agreement issued a call for developed nations to freeze the use and production of CFCs at the 1986 level while cutting 50 percent of use and production by 1999.
Still, the CFCs currently rising through the troposphere will take seven to 10 years to drift up to the stratosphere. The troposphere is the portion of the atmosphere that is below the stratosphere, extending outward about seven to 10 miles from the earth’s surface (Bellamy & Gifford, 2000).
If we are to keep the ozone layer, the use of CFCs must be lowered—if not totally eliminated. Consumers must not patronize products that have CFCs, educators and scientists must challenge students to find alternatives, entrepreneurs and industrialists must avoid the use of CFC-solvent cleaners and policymakers must [ass legislative measures regarding CFCs (Jordan, 2005).
Did the world really act as fast as possible to meet the threat? The answer, unfortunately, is no. The eventual rescue operation was the last chapter in a long saga of confusion, wishful thinking, indecision and delay.
B. Global Warming poses threat to Chinese coast
In Beijing, China the rising sea level will inundate Shanghai, Guangzhou and other major Chinese coastal cities unless drastic measures are taken to slow global warming, according to a new government-backed report.
The report, released by China’s National Environmental Protection Agency, The UN Development Program and the World Bank, listed the threat of widespread flooding as one of the “staggering” environmental implications of China’s rapid economic growth.
By 2050, rising sea levels could threaten 92,000 square kilometers of land—an area the size of Portugal—and displace 76 million people—more than the population of the Philippines. The impact would be concentrated in China’s coastal areas—the powerhouse of the country’s rapid economic growth (Carliner, 2000).
The report, entitled “Issues and Options in China’s Greenhouse Gas Emissions Control,” coincides with a major international conference on climate change in Berlin. It forecast a sea-level rise of up 70 centimeters off Shanghai and 60 centimeters off southern Guangdong province’s booming Pearl Delta region.
“If China’s coastal areas are not protected, a one-meter increase in the sea level will flood regions lying below a four-meter contour line in China’s coastal plains when combined with tide and storm surges,” the report said. While China is set to be a major victim of climate changes resulting from the greenhouse effect, it is also one of the world’s biggest contributors to the problems. China’s 76 percent dependency on coal as an energy source means it now accounts for 10 percent of all carbon dioxide emissions, while the new report estimated that the Asian giant’s demand for the fuel would triple to 3.1 billion tons by 2020 (Jordan, 2005).
Of all issues affecting humanity, climate change is the most pervasive and truly global, posing a very real and serious threat to our environment. Climate change is the alteration of the pattern of global climate that may be due to human activity that alters the composition of the atmosphere. Certain gases in the atmosphere, such as carbon dioxide, play a crucial role in determination the earth’s climate. Although other factors are important as well, the composition of the atmosphere to a large extent controls our climate of which, the so-called “greenhouse gases” (or GHGs) are particularly important.
The earth receives energy continuously from the sun; and must get rid of this energy at the same rate by sending it back out to space. However, greenhouse gases inhibit the ability of this outgoing energy to pass through the atmosphere, and as far their concentrations rise, the climate must somehow adopt, or change to keep the energy budget in balance. One probable change is a warming of the earth’s surface and the lower atmosphere.
If present day emissions of greenhouse gases continue, it is estimated that the rate of increase in global mean temperatures will reach about 0.3° C per decade. This will mean a likely increase of 1° C above the present level by the year 2025, and 3° C before the end of the next century.
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Carwardine, Mark. The WWF Environment Handbook. London: Macdonald Optima, 2000. Attractively illustrated handbook for the general reader.
Cronin, Helena. The Ant and the Peacock: Altruism and Sexual Selection from Darwin to Today. Cambridge: Cambridge University Press, 2001. Chapters 2, 3, 4 (pp. 7-110).
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Durrell, Lee. The State of the Ark. London: Bodley Head, 1999. Popular work, based on research by the International Union for Conservation of Nature and Natural Resources.
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Carliner, Geoffrey. The China Card: Global Warming? Challenge. Volume: 38. Issue: 5. Page 57+, 2000.