The World Faces a Fresh Water Hazard In many places wate

游客2023-11-06  13

问题                     The World Faces a Fresh Water Hazard
    In many places water is becoming scarcer. Treating it as a right makes the scarcity worse. Ideally, efficient water use would be encouraged by charging for it, but attempts to do so have mostly proved politically impossible. A more practicable alternative is a system of tradable water-usage rights.
    As our explains, many water problems have global causes: population growth, climate change, urbanization and, especially, changing diets. It takes 2,000 liters of water to grow a kilo of vegetables but 15,000 liters to produce a kilo of beef—and people are eating more meat. The problems also have global implications. Without a new green revolution, farmers will need 60% more water to feed the 2 billion extra people who will be born between now and 2025.
    Yet there is, globally, no shortage of water. Unlike other natural resources (such as oil), water cannot be used up. It is recycled end-lessly, as rain, snow or evaporation. On average, people are extracting for their own uses less than a tenth of what falls as rain and snow each year.
    The central problem is that so much water is wasted, mainly by farmers. Agriculture uses three-quarters of the world’s water. Because water is usually free, thirsty crops like alfalfa (苜蓿) are grown in arid California. Wheat in India and Brazil uses twice as much water as wheat in America. Dry countries like Pakistan export textiles though a 1 kg bolt of cloth requires 11,000 liters of water.
    Any economist knows what to do: price water to reflect its value. But decades of trying to do that for agriculture have run into powerful resistance from farmers. They reject scarcity pricing for the reason that water falls from the skies. No government owns it, so no government should charge for it.
    There is a way out. Australian farmers have the right to use a certain amount of water free. They can sell that right to others. But if they want more water themselves, they must buy it from a neighbor. The result of this trading is a market that has done what markets do: allocate resources to more productive use. Australia has endured its worst drought in modern history in the past ten years. Water supplies in some farming areas have fallen by half. Yet farmers have responded to the new market signals by switching to less thirsty crops and kept the value of farm output stable. Water productivity has doubled. Australia’s system overcomes the usual objections because it confirms farmers’ rights to water and lets them have much of it for nothing. [br] The author mentions "It takes 2,000 liters of water to grow a kilo of vegetables but 15,000 liters to produce a kilo of beef and people are eating more meat. "(Line 4~7, Para. 2) to______.

选项 A、highlight the importance of new green revolution for our lives
B、urge people to take effective actions to solve water shortage
C、emphasize changing diets mainly contributes to water problems
D、warn people of the trouble of population growth in the future

答案 C

解析 篇章结构题。根据题干提示定位到原文第二段第一句:As our explains,many water problems have global causes:population growth,climate change,urbanization and, especially,changing diets.此处提到许多因水引起的问题具有其全球性的原因,比如人口增长,气候变化,城市化,特别是饮食的改变。随后文章用此例来说明饮食的改变造成的用水问题,因此选[C]项。[A]项和[D]项中提到的绿色革命和人口问题虽然在下文有所提及,但并非作者试图通过此例要证明的问题;[B]项在文中未涉及。
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