作业帮 > 英语 > 作业

英语选修六第四,五单元reading1的课文

来源:学生作业帮 编辑:拍题作业网作业帮 分类:英语作业 时间:2024/04/29 09:43:57
英语选修六第四,五单元reading1的课文
Unit 4
THE EARTH IS BECOMIG WARMER-BUT DOES IT MATTER?
During the 20th century the temperature of the earth ros
e about one degree Fahrenheit. That probably does not seem much to you or me, but it is a rapid increase when compared to other natural changes. So how has this come about and does it matter? Earth care's Sophie Armstrong explores these questions.
There is no doubt that the earth is becoming warmer(see Graph 1) and that it is human activity that has caused this global warmig rather than a random but natural phenomenon.
All scientists subscribe to the view that the increase in the earth's temperature is due to the burning of fossil fuels like coal, natural gas and oil to produce energy. Some byproducts of this process are called "greenhouse" gases, the most important one of which is carbon dioxide. Dr Janice Foster explains: "There is a natural phenomenon that scientists call the "greenhouse effect".This is when small amounts of gases in the atmosphere, like carbon dioxide, methane and water vapour, trap heat from the sun and therefore warm the earth. Without the'greenhouse effect
the earth would be about thirty-three degrees Celsciu cooler than it is. So, we need those gases. The problem begins when we add huge quantities of extra carbon dioxide into the atmosphere. It means that more heat energy tends to be trapped in the atmosphere causing the global temperature to go up.
We know that the levels of carbon dioxide have increased greatly over the last 100 to 150 years. It was a scientist called Charles Keeling, who made accurate measurements of the amount of carbon dioxide in the atmosphere from 1957 to 1997. He found that between these years the carbon dioxide in the atmosphere went up from around 315 parts to around 370 parts per million(see Graph 2)
All scientists accept this data. They also agree that it is the burning of more and more fossil fuels that has resulted in this increase in carbon dioxide. So how high will the temperature increase go? Dr Janice Foster says that over the next 100 years the amount of warming could be as low as 1 to 1.5 degrees Celsius, but it could be as high as 5 degrees.
However, the attitude of scientists towards this rise in completely different. On the one hand, Dr Foster thinks that the trend which increases the temperature by 5 degrees would be a catastrophe. She says, " We can't predict the climate well enough to know what to expect, but it could be very serious." Others who agree with her think there may be a rise of several metres in the sea level, or predict severe storms, floods, droughts, famines, the spread of diseases and the disappearance of species. On the other hand, there are those, like George Hambley, who are opposed to this view, believe that we should not worry about high levels of carbon dioxide in the air. They predict that any warming will be mild with few bad environmental consequences. In fact, Hambley states, "More carbon dioxide is actually a positive thing. It will make plants grow quicker; crops will produce more; it will encourage a greater range of animals-all of which will make life for human beings better."
Greenhouse gases continue to build up in the atmosphere. Even if we start reducing the amount of carbon dioxide and other greenhouse gases, the climate is going to keep on warming for decades or centuries. No one knows the effects of global warming. Does that mean we should do nothing? Or, are the risks too great?
Unit 5
        AN EXCITING JOB
I have the greatest job in the world. I travel to unusual places and work alongside people from all over the world. Sometimes working outdoors, sometimes in an office, sometimes using scientific equipment and sometimes meeting local people and tourists, I am never bored. Although my job is occasionally dangerous, I don't mind because danger excites me and makes me feel alive. However, the most important thing about my job is that I help protect ordinary people from one of the most powerful forces n earth-the volcano.
I was appointed as volcanologist information for a database about Mount Kilauea, which is one of the most active volcanoes in Hawaii. Having collected and evaluated the information, I help other scientists to predict where lava from the volcano will flow next and how fast. Our work has saved man lives because people in the path of the lava can be warned to leave their houses. Unfortunately, we cannot move their homes out of the way, and many houses have been covered with lava or burned to the ground.
When boiling rock erupts from a volcano and crashes back to earth, it causes less damage than you might imagine. This is because no one lives near the top of Mount Kilauea, where the rocks fall. The lava that flows slowly like a wave down the mountain causes far more damage because it buries everything in its path under the molten rock. However, the eruption itself is really exciting to watch and I shall never forget my first sight of one. It was in the second week after I arrived in Hawaii. Having worked hard all day, I went to bed early. I was fast asleep when suddenly my bed began shaking and I heard a strange sound, like a railway train passing my window. Having experienced quite a few earthquakes in Hawaii already, I didn't take much notice. I was about to go back to sleep when suddenly my bedroom became as bright as day. I ran out of the house into the back garden where I could see Mount Kilauea in the distance. There had been an eruption from the side of the mountain and red hot lava was fountaining hundreds of metres into the air. It was an absolutely fantastic sight.
The day after this eruption I was lucky enough to have a much closer look at it. Two other scientists and I were driven up the mountain and dropped as close as possible to the crater that had been formed duing the eruption. Having earlier collected special clothes from the observatory, we put them on before we went any closer. All three of us looked like spacemen. We had white protective suits that covered our whole body, helmets,big boots and special gloves. It was not easy to walk in these suits, but we slowly made our way to the edge of the crater and looked down into the red, boiling centre. The other two climbed down into the crater to collect some lava for later study, but this being my first experience, I stayed at the top and watched them.
Today, I am just as enthusiastic about my job as the day I first started. Having studied volcanoes now for many years, I am still amazed their beauty as well as their potential to cause great damage.