While some people believe the earth’s climatic changes are due to the fact that the
universe is getting older, others believe it is due to the greenhouse effect.
The greenhouse effect is a naturally occuring phenomenon that is responsible for trapping heat near the earth’s surface and keeping the planet warm. It is called the greenhouse effect because the way it works is similar to the way in which a green house functions. In a greenhouse sunlight passes through the transparent roof and walls and strikes the objects inside- plants, flowerpots, tables, and so forth. These objects absorb energy from sun, become warmer, and then give off energy themselves in the form of heat. Only a little of this heat energy passes out through the glass, much of it is “trapped” in the greenhouse, raising the temperature inside.
In some ways, the earth functions rather like a greenhouse except on a much larger scale.
Although the greenhouse effect has only recently been in the news, is nothing new in th history of our planet, has played major role in making life on earth possible. Without the greenhouse effect, the earth would be too cold for living thing to survive. The big question today is “If greenhouse effect is natural, why are people so worried about it. Is soemthing good turning bad?” Up until about 150 years ago the compostion of the earths atmosphere had remianed relatively unchanged for several thousand years. Since mid 1800s certain human activities have been changing the heat trappin ability of the atmospher dramatically, as a result more heat is being trapped by the atmosphere. Scientists have been anticipating this “strengthening” of the greenhouse effect for sometime, and that it will lead to a worldwide increase in temperature. This is come true because the world is getting warmer. Global warming can be expected to change the earth’s climate dramatically and in a relatively short time. As temperatures increase, experts predict that weather patterns will be disrupted worldwide, the glaciers and polar ice caps will, melt, and that sea levels will rise. Global warming could change the atmosphere so much and so fast that all sorts of plants and animals might soon be in danger os extinction. The greenhouse effect may be the most serious environmental problem the human race has ever experienced, for this reason scientists around the world are working hard to acheive a better understanding of the greenhouse effect, to predict the impact it will have on earth, and to discover ways to control it.
The greenhouse effect occurs when gases such as methane, carbon dioxide, nitrogen oxide and CFCS trap heat in the atmosphere by acting as a pane of glass in a car. The glass’ lets the sunlight in to make heat, but when the heat tries to escape, the gases reabsorb it. Holding this heat in causes heat waves, droughts and climatic changes which could alter our way of living. The greenhouse effect, in environmental science, is a popular term for the effect that certain variable constituents of the Earth’s lower atmosphere have on surface temperatures. “It has been known since 1896 that the Earth has been warmed by a blanket of gases. The gases; water vapour (H2O), carbon dioxide (CO2), and methane (CH4) keep ground temperatures at a global average of about 15 degrees C.” (Oppenheimer, p. 119-120) Without them, the average would be below the freezing point of water. The gases have this effect because as incoming solar radiation strikes the surface, the surface gives off infrared radiation, or heat, that the gases trap and keep near ground level. Environmental scientists are concerned that changes in the variable contents of the atmosphere, particularly changes caused by human activities, could cause the Earth’s surface to warm up to a dangerous degree. “Since 1850 there has been a mean rise in global temperature of approximately 1 degree C.” (Gribbin, p. 14) Even a limited rise in average surface temperature might lead to at least partial melting of the polar icecaps and hence a major rise in sea level, along with other severe environmental disturbances.
What is meant by the term, the greenhouse effect, is that the heat from the sun comes into the Earth’s atmosphere and cannot get out so it becomes trapped. This effect occurs when the incoming short wave radiation hits the Earth’s surface it changes into longwave, or infrared radiation. Heat energy in this form is then absorbed and stored in water vapour and carbon dioxide in the atmosphere.
The main gases that cause the greenhouse effect are water vapour, carbon dioxide (CO2), and methane which comes mainly from animal manure. Other gases like nitrogen oxide and man made gases called chlorofluorocarbons get caught in the atmosphere as well. The decay of animals and respiration are two main but natural sources of carbon dioxide.
Water vapour is an important “greenhouse gas”. It is a major reason why humid regions experience less cooling at night than do dry regions. However, variations in the atmosphere’s carbon dioxide content are what have played a major role in past climatic changes. In recent decades there has been a global increase in atmospheric carbon dioxide, largely as a result of the burning of fossil fuels. If the many other determinants of the Earth’s present global climate remain more or less constant, the carbon dioxide increase should raise the average temperature at the Earth’s surface. As the atmosphere warmed, the amount of water vapour would probably also increase, because warm air can contain more water than cooler air. This process might go on indefinitely. On the other hand, reverse processes could develop, such as increased cloud cover and increased absorption of carbon dioxide by phytoplankton in the ocean. These would be natural feedbacks, lowering temperatures.
Many different things cause The greenhouse effect. “The amount of carbon dioxide in the atmosphere is increased by 0.4 percent each year because of the massive consumption of fossil fuels such as oil, coal, and natural gas.” (McCuen, p. 77) Another contributing factor is the amount of forest logged. Every second of the day the area of a football field is cleared of trees by either being logged or burnt. Two other deadly greenhouse gases which are entering the atmosphere even faster than carbon dioxide are methane and chlorofluorocarbons, although they are not as damaging in the long run.
These increases are likely to affect worldwide temperatures dramatically. “In 100 years time the average temperature for most parts of the world will increase from between 2 degrees C to 6 degrees C if greenhouse pollution continues at its present rate.” (Baines, p. 190) This temperature increase would drastically affect the growth of many different crops and cause the polar ice caps to melt, thus increasing sea levels. If this rise in sea level was to occur many areas would be much more prone to flooding, and generally much deeper floods would be experienced than nowadays. This flooding would happen particularly around coastal regions worldwide, and also along many rivers that flow to or from coastal inlets.
The greenhouse effect is very important because it leads to rising water levels and temperatures which can have a large effect on the world’s climate. Changes in the climate can lead to significant changes in agricultural industries. This can lead to good farmland becoming deserts, make it too hot for some crops to grow or let pests and diseases thrive. As a result some countries can suffer bad economic conditions and people will have to move.
It would seem logical that the entire world should try and slow down the emission of greenhouse gases and/or find ways to balance the gases so the climate doesn’t change so rapidly. If it did we would be forced to adapt to the new climate that we brought upon ourselves. If we had an international cooperation to put a damper on the production of chlorofluorocarbons and slow down the use of fossil fuels it would dramatically slow down the process of “global warming”.
Over the last 100 years the global temperatures have been increasing slowly but steadily. “Since 1980 the temperature has risen 0.2 degrees C each decade.” (Clayton, p. 113) Scientists predict that if we continue putting the same amount of gas into the atmosphere, by the year 2030 the temperature will be rising by as much 0.5 degrees C or more per decade. Overall, the global temperature could rise anywhere from 5 to 9 degrees over the next fifty years.
If the temperatures do rise as predicted several things could happen. The increases of temperature could alter the growth of crops in areas near the equator due to insufficient rain and heat. This could really hurt countries that rely on imported food supplies. With the introduction of high temperatures in the arctic regions the polar ice caps could melt and cause the sea water level to go up 1 to 3 feet, this of course would occur gradually over an extended period of time. This increase could take out small islands, coastal cities and some shallow rivers. The Everglades in Florida would almost be totally wiped off the map. The Everglades are home to many animals and plant species. If it did get flooded, they would all have to move northward across into very dry land, which they would not be able to endure living on for very long. When the hot temperatures do spread southward and northward, tropical diseases will be hard to deal with, causing more deaths and illnesses than before. The financial problem with this is that the flooding will cause dams to be built and cities to be reconstructed. The shortage of food will cause the price of the food to go up and with all the diseases we will need more medical supplies and workers. All of this combined could and will cost a lot of money if we don’t do something about it now.
The computer models can’t predict exactly what the climate is going to be in the future, but they can come close to what it will be like down the road. Scientists proved this by predicting with computers what the climate was in the past. Then by looking back in the records, they found that the predictions were close to being right.
The “Topex” (Topographic Experiment) satellite has been collecting information on the changes of the sea level, temperatures across the globe and the amount of gases emitted into the atmosphere. Each day the satellite makes 500,000 measurements, each at a different place on the Earth’s surface. Measurements are all made between 66 degrees north and south latitudes.
The Cretaceous Period occurred over 100 million years ago. It was the warmest period we have knowledge of yet. There was so much carbon dioxide in the air that the oceans rose many metres. North America was flooded and split apart into two pieces. The temperature then was more than fifteen degrees greater than the average temperature today.
Scientists believe that the tilt of the earth’s axis changes to tilt the opposite way every 10,000 years like a cycle. While going through this cycle it will change the climate of areas. Right now it is moving so that North America is going to be close to the sun in the winter. Seasons become more extreme when the opposite happens. This controls the cycle of ice ages. When volcanoes erupt they send clouds of dust into the air blocking sunlight. This would cool the earth off more. Oceans are known to absorb carbon dioxide because of the ocean currents and the action of plankton. There is some evidence that there is naturally rapid climate change between each Ice Age, which confuses the whole idea of global warming.
It is necessary that every human being should take part in the fight to stop global warming. The government is the key to this and they better do something soon or it will be too late. First, the Canadian government should sponsor a meeting between the nations of the world. They should establish a committee for handling the money, politics, and scientific research, in order to help cut back the emission of gases into the atmosphere. Every country will contribute by donating money. Each country would be required to give 0.01 of their GNP to this committee. If they refuse they will be boycotted and nothing will be sold to them by participating countries.
Global warming is a big threat to our nation and the world. If we do not act now, it may be too late. Of course, there is no sure way of telling if there is a greenhouse effect, but let’s not take any chances. Look at what is happening to this world, and you will see that there is a pollution problem. There are steps being taken at this moment to reduce the gases put into the air but this is still not enough. We need to cut back more by taking a few easy steps. Plant a tree, or take the bus to work or school instead of driving your own car. Those things might not seem like a lot, but if more and more people do them, they will make a difference.