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THE GREENHOUSE EFFECT


Scientists say that something very serious is happening to the Earth. It will begin to get warmer in the 1990s. There will be major changes in climate during the next century. Coastal waters will have higher temperature. This will have a serious effect on agriculture. In northern areas, the growing season will be ten days longer by the year 2000. However, in warmer areas, it will be too dry. The amount of water could decrease by fifty percent. This would cause a large decrease in agricultural production


World temperatures could increase two degrees centigrade by the year 2040. However, the increase could be three times as great in the Arctic and Antarctic regions. This could cause the ice sheets to melt and raise the level of the oceans by one or two meters. Many coastal cities would be under water


Why is this happening? There is too much carbon dioxide ( CO2 ) in the air. When oil, gas, and coal burn, they create large amounts of carbon dioxide. We send five billion tons of carbon dioxide into the atmosphere every year. This amount will double in fifty years. This carbon dioxide lets sunlight enter the Earth's atmosphere and heat the Earth. However, it does not let as much heat leave the atmosphere and enter space. It is like a blanket. The heat can pass from the sun through the blanket to warm the Earth. The heat stays there and cannot escape through the blanket again


Scientists call this the greenhouse effect. A greenhouse is a building for growing plants. It is made of glass or clear plastic


These scientists say we must start planning now. We need to do research so we can predict what will happen. We must conserve coal, oil, and gas


However, other scientists disagree. They say there is no reason to worry because we have twenty years to plan. They think that the greenhouse effect will not be very serious. They believe that there is no way for the world to slow this down or stop it. We must just prepare for a high-temperature world


These scientists also say that the causes of the world climate are very complicated. The greenhouse effect is only one cause. Other gases and dust in the air and changes in clouds are also important to the climate of the Earth


Meanwhile, all scientists agree that we must continue measuring the amount of carbon dioxide in the atmosphere and observing its effects. Scientists must encourage this research so the world will be ready if the greenhouse effect really occurs

Source : Concepts and Comments

دسته ها : English Readings
پنج شنبه یازدهم 12 1390 17:14
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