全新版大学英语听说教程第四册 unit15（在线收听）

Unit 15

Part B

Good News about the Environment

     Scientists and environmentalists have constantly warned us of the worsening state of our environment. Their view can be summarized in the list below:

     ● Our resources are running out.

     ● The population is growing ever larger, leaving less and less for everyone to eat.

     ● The air and water are becoming ever more polluted.

     ● Large numbers of the planet's species are threatened with extinction.

     Many people agree with such views. However, a Danish statistician named Bjorn Lomborg argues for an opposite point of view. In his opinion, the available evidence does not back up this list of environmental problems. He argues that there are no shortages of energy resources; that fewer people are starving today; that species are not disappearing at an alarming rate; and that growth is the solution to environmental problems like pollution and global warming.

     Let us examine his views in more detail on two environmental issues.

     Firstly, are Earth's energy resources running out? According to Lomborg, the mineral resources on which modern industry depends are not running out. He argues, for example, that known reserves of fossil fuels and most commercially important metals are now much larger than they were 30 years ago and that known oil reserves that could be extracted at reasonably competitive prices would keep the world economy running for 92 years at present consumption rates.

     He argues that although we consume an increasing amount of these resources, we've discovered even more. We have also become more efficient and less wasteful in extracting and exploiting them.

     The story is the same for non-energy resources, says Lomborg. Despite an astounding increase in production and consumption, the available reserves of the most important resources -- aluminum, iron, copper, and zinc -- have grown even more, and their prices have also declined over the past century.

     Meanwhile, Lomborg says, the cost of both solar and wind energy has dropped by more than 90 per cent over the past 20 years, and within 50 years, solar energy will probably be available at competitive prices.

     Turning to a second environmental issue, is pollution a serious problem facing mankind? Lomborg holds that pollution is no longer undermining our well-being because its burden has diminished dramatically in the developed world. Progress in dealing with air pollution in the developed world has been unequivocal and human health has benefited phenomenally from reductions in lead and particle concentration. He points out, for example, that the air in London is today cleaner than it has ever been since 1585.

     However, Lomborg admits that air pollution has become worse in the developing world because of strong economic growth. But he argues that growth and the environment are not opposites. They complement each other. Without adequate protection of the environment, growth is undermined. But without growth, it is not possible to support environmental protection.

     Lomborg is confident that when developing countries attain higher levels of income, they will opt for, and be able to afford, an ever-cleaner environment. According to Lomborg, things are generally getting better, and they are likely to continue to do so. No environmental catastrophe is likely to emerge.

     If Lomborg is right, we humans will have little to worry about our environment for the time being. But can we rely on what he has to say?

Part C

Disappearing Species?

     Assertions of the world's massive species extinction are repeated everywhere you look. It is commonly believed that between 20,000 and 100,000 species are lost every year. Yet they simply do not equate with the available evidence.

     The theory of biodiversity loss equates the number of species to area: the more space there is, the more species can exist. A rule of thumb, which works well for islands, is that if the area is reduced by 90%, the number of species will be reduced by half.

     Thus, as rainforests were cut at alarming rates, many people expected the number of species to fall by half globally within a generation or two.

     In the United States, however, the primary eastern forests were reduced over two centuries to just one to two per cent of their original area. However, this resulted in the extinction of just one forest bird.

     Brazil's Atlantic rainforest was almost entirely cleared in the 19th century, leaving only some 10 per cent scattered fragments. The rule of thumb would expect half of the species to be extinct. However, in 1989 members of the Brazilian Society of Zoology could not find a single known animal species that could properly be declared as extinct. Indeed, an appreciable number of species considered extinct 20 years ago, including several birds and six kinds of butterflies, have been rediscovered more recently.

     Species seem to be more resilient than expected. The UN Global Biodiversity Assessment estimates an extinction rate of 0.1 to one per cent over the next 50 years. That figure is certainly not trivial. But it is much smaller than the 10 to 100 per cent typically suggested in the media and elsewhere.

Questions:

1. How many species are commonly believed to be lost every year?

2. According to the rule of thumb used to predict the rate of extinction, if a forest is reduced to 10% of its original size, how many of its species will become extinct?

3. How many species were lost because of the shrinking of the eastern forests in the US according to the text?

4. What point does the speaker want to make by giving the examples of the US eastern forests and Brazil's Atlantic rainforest?

5. What is the main argument of the passage?

Part D

How Green Is Our Valley?

(By Joe Thorton)

    In his article "Measuring the Real State of the Planet", Bjorn Lomborg depicts a world as illusory as the Land of Oz. His Oz is a place with no serious environmental afflictions. Global warming? Lomborg, who teaches statistics at Aarhus University in Denmark, argues that by the time elevated temperatures lead to flooding and declining agricultural yields, developing countries will be rich enough to cope just fine. Ozone depletion? Most of the skin cancer it causes won't be fatal. Toxic chemicals in the food supply and in groundwater? Less likely to cause cancer than a cup of coffee.

     But utopias are boring, so the author offers up some villains: environmental organizations and scientists whom he claims are engaged in a vast conspiracy to convince the public that the world's ecosystems are breaking down. Lomborg sets out to criticize a long list of claims that he attributes, though not always accurately, to self-interested environmentalists. That he takes an anti-environmentalist position on virtually every issue should raise serious questions about his objectivity. Moreover, his own analysis often doesn't hold up under scientific scrutiny.

     Lomborg argues, for example, that the world's forests are not really in trouble, because estimates of global forest cover have increased slightly over the last several decades. But Lomborg counts tree farms and second-growth forests together with old-growth ones, although only the latter provide the complex habitats necessary to sustain biodiversity. He also claims that chemical pollutants in the ocean are at biologically insignificant levels. But he omits the fact that many chemical pollutants accumulate in the food chain. Their levels of concentration in predator species are millions of times greater than their concentration in the water -- levels high enough to pose health risks to whales, seals, and people.

     The wizard in L. Frank Baum's book forces his people to wear green spectacles that make Oz appear perfectly beautiful. Likewise, Lomborg promises a nearly perfect world of easy environmental progress if we put our faith in economic growth unhindered by government regulation. But this view ignores a crucial reality: The real success stories of the last three decades, including big reductions in environmental levels of ozone-depleting chemicals, DDT, PCBs, lead, and other pollutants, were accomplished not through the free market but through strict government restrictions on the production of these substances. Today's environmental challenge is to expand on these lessons and to base development on ecologically sound technologies, a goal we can reach only through ambitious action, both public and private.

Statements:

1. Bjorn Lomborg denies the existence of environmental problems such as global warming and ozone depletion.

2. Lomborg criticizes scientists and environmental organizations for suppressing the truth about the environment out of self-interest.

3. The speaker argues that there are flaws in Lomborg's analysis of data.

4. According to Lomborg, government regulation holds the key to environmental progress.

5. The speaker attributes the environmental improvement made in the last three decades largely to economic growth.

6. The speaker compares the world described by Lomborg to the Land of Oz because both are unreal.