普通高中课程标准实验教科书 英语选修6 Unit 4 Global warming-R

THE EARTH IS BECOMING WARMER-BUT DOES IT MATTER?

      During the 20th century the temperature of the earth rose about one degree Fahrenheit¹. 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 warming rather than a random² but natural phenomenon.

 

     All scientists subscribe³ 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, methane⁴ 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 Celsius⁵ 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 is completely different. On the one hand, Dr Foster thinks that the trend which increases the temperature by 5 degrees would be a catastrophe⁶. 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 disappearance⁷ 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?

1 Fahrenheit   

n./adj.华氏温度；华氏温度计(的)

参考例句：

• He was asked for the boiling point of water in Fahrenheit.他被问到水的沸点是华氏多少度。
• The thermometer reads 80 degrees Fahrenheit.寒暑表指出华氏80度。

2 random   

adj.随机的；任意的；n.偶然的(或随便的)行动

参考例句：

• The list is arranged in a random order.名单排列不分先后。
• On random inspection the meat was found to be bad.经抽查，发现肉变质了。

3 subscribe   

vi.(to)订阅，订购；同意；vt.捐助，赞助

参考例句：

• I heartily subscribe to that sentiment.我十分赞同那个观点。
• The magazine is trying to get more readers to subscribe.该杂志正大力发展新订户。

4 methane   

n.甲烷，沼气

参考例句：

• The blast was caused by pockets of methane gas that ignited.爆炸是由数袋甲烷气体着火引起的。
• Methane may have extraterrestrial significance.甲烷具有星际意义。

5 Celsius   

adj.摄氏温度计的，摄氏的

参考例句：

• The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
• The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。

6 catastrophe   

n.大灾难，大祸

参考例句：

• I owe it to you that I survived the catastrophe.亏得你我才大难不死。
• This is a catastrophe beyond human control.这是一场人类无法控制的灾难。

7 disappearance   

n.消失，消散，失踪

参考例句：

• He was hard put to it to explain her disappearance.他难以说明她为什么不见了。
• Her disappearance gave rise to the wildest rumours.她失踪一事引起了各种流言蜚语。