大学英语听力教学课件第三册听力原文(第二版张民伦主编~).doc

|大学英语听力教程第三册（第二版） 听力原文UNIT1 Is the Earth Being Squeezed DryPart1 Getting readySection B 1. The Amazon forests are disappearing because of increased burning and tree removal. In September, satellite pictures showed more than 20000 fires burning in the Amazon. Experts say most of these fires were set by farmers. The farmers were attempting to clear land to grow crops. The World Wildlife Fund says another serious problem is that too many trees in the Amazon rain forest are being cut down. The World Wildlife Fund says the fires show the need for urgent international action to protect the world's rain forests. The group warns that without such action some forests could be lost forever.2. Environmental issues swell to the full in Berlin this week, for the UN sponsored conference on global warming and climate change is the first such meeting since the Rio summit three years ago. With scientists and governments now generally ready to accept that the earth climate is being affected by emissions of CO2 and other greenhouse gases, over a hundred countries are sending delegations. But how much progress has been made implementing the greenhouse gas reduction target agreed on at Rio? Simon Dary reports.Part2 The Earth at risk (1)I: Brian Cowles is the producer of a new series of documentaries called “The Earth at Risk“ which can be seen on Channel 4 later this month. Each program deals with a different continent, doesn't it, Brian? B: That's right. We went to America, both North and South and then we went over to Africa and South-East Asia. I: And what did you find in each of these continents? B: Starting with Africa, our film shows the impact of the population on the environment. Generally speaking, this has caused the Sahara Desert to expand. It's a bit of a vicious circle we find. People cut down trees for firewood and their domestic animals eat all the available plants and so consequently they have to move south as the Sahara Desert expands further south. I mean, soon the whole of Mali will become a desert. And in East Africa: here the grasslands are supporting too many animals and the result is, of course, there's no grass nothing for the animals to eat. I: I see. And the next film deals with North America? B: That's right. In the USA, as you know, intensive agriculture requires a plentiful supply of rain for these crops to grow; I mean if there isn't enough rain the crops don't grow. And growing crops stabilize soil, without them the top soil just blows away. This is also true for any region that is intensely farmed most of Europe, for example. I: And what did you find in South America? B: In South America (as in Central Africa and Southern Asia) tropical forests are being cut down at an alarming rate. This is done so that people can support themselves by growing food or to create ranches where cattle can be raised to be exported to Europe or America as tinned meat. The problem is that the soil is so poor that only a couple of harvests are possible before this very thin soil becomes exhausted. And it can't be fed with fertilizers like agricultural land in Europe. For example, in Brazil in 1982 an area of jungle the size of Britain and France combined was destroyed to make way for an iron ore mine. Huge numbers of trees are being cut down for exports as hardwood to Japan, Europe, USA to make things like luxury furniture. These forests can't be replaced the forest soil is thin and unproductive and in just a few years, a jungle has become a waste land. Tropical forests contain rare plants (which we can use for medicines, for example) and animals one animal or plant species becomes extinct every half hour. These forest trees also have worldwide effects. You know, they convert carbon dioxide into oxygen. The consequence of destroying forests is not only that the climate of that region changes (because there is less rainfall) but this change affects the whole world. I mean, over half the world's rain forest has been cut down this century. Part3 The Earth at risk (2)|Section AI: So, Brian, would you agree that what we generally think of as natural disasters are in fact man-made? B: Yes, by and large. I mean, obviously not hurricanes or earthquakes, but take flooding, for example. Practically every year, the whole of Bangladesh is flooded and this is getting worse. You know, the cause is that forests have been cut down up in Nepal and India, I mean higher up-river in the Himalayas. Trees would hold rainfall in their roots, but if they've been cut down all the rain that falls in the monsoon season flows straight into the river Ganges and floods the whole country. The reason for flooding in Sudan is the same the forests higher up the Blue Nile in Ethiopia have been destroyed too. I: Well, this all sounds terribly depressing. Um . What is to be done? I mean, can anything be done, in fact? B: Yes, of course it can. First, the national governments have to be forward-looking and consider the results of their policies in ten or twenty years, not just think as far ahead as the next election. Somehow, all the countries in the world have to work together on an international basis. Secondly, the population has to be controlled in some way: there are too many people trying to live off too little land. Thirdly, we don't need tropical hardwood to make our furniture it's a luxury people in the West must do without. Softwoods are just as good, less expensive and can be produced on environment-friendly “tree farms“, where trees are replaced at the same rate that they are cut down. I: And, presumably, education is important as well. People must be educated to realize the consequences of their actions? B: Yes, of course. I: Well, thank you, Brian.Section B I: So, Brian, would you agree that what we generally think of as . er. as er . natural disasters are in fact man-made? B: Yes, by and large . er . I mean, obviously not hurricanes or earthquakes, but take flooding, for example. I mean, practically every year, the whole of Bangladesh is flooded and this is getting worse. You know, the cause is that forests have been cut down up in Nepal and India . I mean . higher up-river in the Himalayas. Trees .er . would hold rainfall in their roots, but if they've been cut down all the rain that falls in the monsoon season flows straight into the river Ganges and floods the whole country. The reason for flooding in Sudan is the same the forests higher up the Blue Nile in Ethiopia have been destroyed too.Part4 The world is warming up. We know this because average temperatures are the highest since scientists started measuring them 600 years ago. The increase is about 0.2 every year. This may seem very slight, but we know that slight changes in temperature can have a big effect on other things. Most scientists now believe this global warming is due to human activity. Jeff Jenkins is head of Britain's Climate Prediction Center. He explains how global warming can happen. “Sunlight strikes the earth and warms it up. At the same time heat leaves the earth, but part of that is trapped by carbon dioxide and other gases in the earth's atmosphere. That has been happening ever since the earth was formed. But the fear is that increasing amounts of carbon dioxide produced by industrial processes and transport and so on will lead to a greater warming of the earth's surface. So that's the global warming that people are concerned about.“ People are most concerned about the use of fossil fuels. Fossil fuels are oil, coal, wood and so on. When these burn, they produce the gas carbon dioxide. Many scientists agree that an increase in the amount of carbon dioxide and some of the gases in the atmosphere will increase the amount of warming. Computers are being used to predict what this may mean. They showed that there could be great changes in rainfall and the rise in the sea level as ice caps in the north and south poles melt. This could have a serious effect on agriculture according to Prof. Martin Perry of University College in London. He says it could become more difficult to grow food in the tropics at lower latitudes nearer to the equator. |“The most clear pattern emerging is the possibility of reduced potential production in lower latitude regions, and most generally speaking, increased potential in higher latitude regions. Lower latitude regions are already warm, to put it extremely simply, and plants there are quite near their limits of heat and drought stress. An increase in temperature or reduction in moisture would place limits on crop growth.“ Woman: Global warming could reduce food production in lower latitude regions. Lower latitude regions are already warm. Global warming could put more stress on plans and place limits on crop growth. Food production is only one area that could be affected. There could also be health and social problems. Prof. Antony MacMichael of the London School of Hygiene and Tropical Medicine believes that some rural areas are already suffering. And the insects and bacteria could spread disease more easily.“Already a number of rural populations around the world are suffering from the decline of agricultural systems. Climate change would add to this. And we would expect that it would accelerate the flood of environmental refugees around the world. But it includes not just the food production systems, but the patterns of distribution of insects and infective agents around the world. It includes likely effects on patterns of hear-related food poisoning, water contamination and diarrhea diseases, lots of things like this that would respond sensitively to changes in climate.“Woman: Global warming could affect the distribution of insects. Global warming could change patterns of heat-related food poisoning. Many countries now agree that something must be done to reduce the danger of global warming. But a worldwide agreement on lowering the production of carbon dioxide has been difficult to reach. This is because many economies depend on fossil fuels like oil. Scientists believe it's now the politicians in every region of the world who need to take action. Part5 Do you know?Environment has taken rather a back seat politically since the Earth summit in Rio de Janeiro nearly 5 years ago. But the problems that meeting highlighted had not gone away. One environmental think tank the International Food Policy Research Institute has been looking at the future of water and its report reflects growing concern at the huge leap in usage over the past few years.In some parts of the world, water consumption has increased five fold. And the institute, known by its initials IFPRI, says shortages could soon become the trigger for conflict and a major barrier to feeding the world's growing population. Here's Richard Black of our Science Unit.“It's often been said that water rather than oil will be the cause of warfare in the next century. According to the IFPRI report, the time when that happens might not be far away. The number of people affected by water shortage will increase ten fold over the next 30 years, it says, which could well lead to large scale conflicts.The main reason why water is becoming a scarce resource is agriculture, which now accounts for 70% of water consumption worldwide, 90% in some developing countries. Countless farmers have switched from growing indigenous crops for the home market to high yield export varieties, which inevitably need far more water. But the IFPRI report says that in some regions water shortage is now the single biggest impediment to feeding the population. Water scarcity also leads to water pollution. In the Indian State of West Bengal, for example, over extraction of water from bore holes has led to arsenic poisoning which is estimated to have affected two million people so far. But the IFPRI report calls for better water management worldwide including financial incentives to encourage conservation.“-Unit 2Part1 Getting readyA: Hello, I'm calling on behalf of the World Wildlife Fund. B: The what? A: The World Wildlife Fund. If you've got a few minutes I'd like to tell you what that means. B: Oh, all right. |A: We work to conserve natural areas that contain endangered wildlife. The seas, for example, have become polluted by the industrialized world; whales are being hunted to extinction; turtles are rolled off their eggs when they come ashore to breed or are slaughtered for their meat and oil B: Oh. A: Crocodiles are killed to make handbags and shoes; walruses are hunted for their ivory. B: I see. A: Seals are bludgeoned to death to provide fur coats and the threat of extinction hangs over several species of whale, dolphin and porpoise. B: Really. A: We are now campaigning to provide sea sanctuaries for some of these endangered species. B: Very interesting. A: Aided by our campaign, protected nesting sites for turtles have already been set up. As you can see, this is very valuable work and I wonder therefore if you'd like to make a donation?Part2 John James Audubon was an American artist in the early 1800s, who illustrated birds in their natural habitats. The Society named after him was founded in the late 1800s by conservationists concerned with the decline of birds, which were being killed so their feathers could be used in the manufacture of women's hats.Sponsored by the National Audubon Society, more than 40 000 volunteers will be outside counting birds from today until January 3rd. Volunteers from all 50 states of the United States, every Canadian province, parts of Central and South America, Bermuda, the West Indies and Pacific islands have begun to count and record every individual bird and bird species observed during the two and one half week period of the count.Jeffrey LeBaron is the National Audubon Society's Christmas Bird Count editor. He says the count is the longest-running bird census in ornithology.This year, according to Mr. LeBaron, more than 1 600 separate bird counts have been scheduled. Some would have as few as 10 people taking part, others with hundreds. The logistics of the Christmas bird count, he adds, are simple.“Each individual count is in a circle. It's a 15 mile diameter circle, um, around the exact center point. And it's always the exactly same area that's done every year, usually, even on the same weekend during the count period. And what the ideal would be, which is virtually impossible, is this census: every single individual bird within that circle on the count day.“Mr. LeBaron says experienced bird counters can get a good idea of the total bird populations within the count circle based on the number of birds they actually see. The editor points out, however, that the counts are not only for experienced bird watchers.“Anybody that is interested or concerned can become inv