高中英语人教版选修6课文朗读04

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[00:00.00]和谐英语学习网 Unit 4
[00:07.60]Global warming
[00:09.64]Reading
[00:12.09]THE EARTH IS BECOMING WARMER-BUT DOES IT MATTER?
[00:17.45]During the 20th century the temperature of the earth rose about one degree Fahrenheit.
[00:24.61]That probably doesn’t sound very much to you or me but it is a rapid increase compared to most natural changes.
[00:33.38]So how has this come about and does it matter?
[00:37.51]Earth Care’s Sophie Armstrong explores these questions.
[00:37.73]There is no doubt that the earth is becoming warmer(see Graph 1) but there is fierce debate over whether it is buman activity that has caused this global warming or whether it is just a natural Phenomenon.
[00:57.58]Many scientists believe that people have caused the increase in the earth’s temperature through the burning of fossil fuels like coal, natural gas and oil to produce energy.
[01:09.15]Some byproducts of this process are called “greenhouse” gases, the most important one being carbon dioxide.
[01:17.98]Dr Janice Foster explains, “you see, there is a natural phenomenon that scientists call the ‘greenhouse effect’.
[01:28.14]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.
[01:41.91]Without the ‘greenhouse effect’, the earth would be about thirty-three degrees Celsius cooler than it is .
[01:49.36]so, we need those gases.
[01:52.39]The problem begins when we add huge quantities of extra carbon dioxide to the atmosphere by burning fossil fuels.
[02:04.22]The increased amount of carbon dioxide means that more heat energy is trapped in the atmosphere causing the global temperature to go up.”
[02:15.30]We know that the levels of carbon dioxide have increased greatly over the last 100 to 150 years.
[02:25.33]It was a scientist called Charles Keeling who made accurate measurements of the amount of carbon dioxide in the atmosphere from 1957to 1997.
[02:38.57]he found that, between these years , the carbon dioxide content of the atmosphere went up from around 315 parts per million to around 370 parts per million(see Graph 2).
[02:56.52]All scientists accept this data.
[03:00.28]They also believe it is the burning of more and more fossil fuels that is resulting in this increase in carbon dioxide.
[03:10.13]But there are some very different attitudes among scientists towards this issue.
[03:16.37]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 much as 5 degrees Celsius.
[03:33.22]“An increase of five degrees would be a catastrophe, I would say.
[03:39.64]We can’t predict the climate well enough to know that to expect.
[03:43.88]But it could be very serious.”
[03:46.93]How serious?
[03:49.10]Some people think future global warming would cause the sea level to rise by several metres;
[03:56.86]others predict severe storms, droughts, famines , the spread of diseases, and the destruction of species.
[04:06.71]On the other hand, there are those, like scientist George Hambley,
[04:12.56]who believe that we should no worry about high levels of carbon dioxide in the air and that some scientists’ concerns about global warming are just speculation.
[04:25.31]He predicts that any warming will be mild with few bad environmental consequences.
[04:33.25]In fact, he states, “more carbon dioxide is actually a positive thing.
[04:40.22]It will make plants grow faster; crops will produce more; it of which will make life for human beings better.”
[04:52.66]Greenhouse gases continue to build up in the atmosphere.
[04:58.59]Even if we start reducing the amount of carbon dioxide and other greenhouse gases, the climate is going to deep on warming for decades or centuries.
[05:10.50]No one knows what the effects of global warming will be .
[05:14.94]Does that mean we should do nothing?
[05:18.28]Or, are the risks too great?
[05:21.65]Using Language
[05:29.59]Reading and discussing
[05:31.94]WHAT CAN WE DO ABOUT GLOBAL WARMING?