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Water scarcity【不足；缺乏】 is becoming an increasingly serious problem in many countries. According to the UN World Water Development Report 2020, 2.2 billion people around the world do not have access to safely managed drinking water. 【全世界22亿人没有办法获得安全管理的饮用水】What can people do to solve water shortage problems? Read the text and find out how vegetarianism, desalination【海水淡化】, cloud seeding【云中散播（促进降雨的技术）】, and reducing water consumption in manufacturing sector might relate to solving the problem.
Thirstier than ever
1 Water covers approximately 75% of the Earth's surface, yet only 3% of it is drinkable; the rest is salt water. Of the little that is fresh, a staggering【adj. extremely great or surprising令人吃惊的是99%的可饮用水藏在地球冰川之下，只有很小一部分是新鲜的饮用水 】 99% is inaccessible, buried deep beneath the world's glaciers. According to Kummu et al. (2010), roughly a third of the world's population is at risk from water scarcity, and population growth is only exacerbating the issue【世界上约有三分之一的人缺水，人口增长只会加速这一问题】. Not only does our species need water to survive, we also rely heavily on it to water our crops【农作物crop的复数】 and sustain our livestock—people typically drink around five liters【公升】 of water per day, while agriculture accounts for【占……比例】 the majority of global fresh water consumption. In some parts of the world, water scarcity severely【非常严重地；严厉地】 limits food production capabilities. Coumou and Rahmstorf (2012) have also forecast that climate change will increase precipitation variability【降水量变率】 (i.e. the frequency of rain), raising the risk of flooding and drought that blight food production. So, what solutions are available to ensure a consistent and stable fresh water supply?
2 The agricultural sector accounts for approximately 70% of global fresh water consumption—double that of industrial and domestic use combined. While more efficient irrigation practices could reduce this volume by an estimated 30%–70%, cutting consumption of animal products【动物制品】 for【为了】 less water-intensive crops would also have a perhaps unexpectedly significant impact. Some people advocate【提倡】 a switch to a vegetarian or vegan diet on the basis that【在此基础上】 the production of meat is much more water-intensive than the production of grains and vegetables. Mekonnen and Hoekstra (2012) estimated that on average, 10,412 liters of water are required for the production of one kilo【千克】 of lamb. Goat requires around 5,521 liters per kilo, poultry【家禽】 4,325 liters per kilo, and beef approximately 15,400 liters per kilo. The variations in water consumption are largely due to the animal feed required. Some animals are much more water-intensive to produce and thus their water footprint【占用空间；覆盖区】 is higher. When we compare these meats to a range of【一系列；许多的】 vegetables we can see that, in general, the cultivation of vegetables is far less water-intensive【耗水量】—cabbage requires 237 liters per kilo, and tomatoes a mere 214 liters per kilo. Based on this evidence, it is clear that a switch to a vegetarian or even vegan【纯素食主义】 diet would dramatically reduce the amount of water consumed by agriculture. However, in virtually【几乎】 every country apart from India, the percentage of vegetarians equates to【相当于】 less than 10% of the total population. This casts some doubt as to whether this solution could work as there would need to be huge cultural shifts in dietary attitude.
3 In areas regularly stricken by water shortages, but wealthy enough to address the issue, desalination—the removal of salt from seawater—offers a viable solution. The most common method of desalination is reverse osmosis【逆向渗透】. Salt water is forced through an ultrathin【超薄的】, semi-permeable membrane, trapping salt molecules【盐分子】 and other toxins【毒素toxin的复数】 on one side. The result is fresh, drinkable water, yet the sheer volume【巨量的】 of pressure required makes it an energy-intensive process. In addition, despite claims to the contrary, desalination is fairly inefficient. According to the International Desalination Association, 18,426 desalination plants produced a mere 86.8 million cubic meters【亿立方米】 of water per day in June 2015, only enough water to meet the needs of 1% of the world's population. Desalinated water also comes at a high price. At $3 per cubic meter, it costs around double that of traditional purification methods such as sedimentation【沉积净化】. However, according to Professor Raphael Semiat, the costs vary greatly depending on location (Johnston, 2015). For example, it can be far more expensive and energy-intensive to pump fresh water from 200 kilometers away, than it would be to desalinate and use water on the coast. While desalination is arguably a necessary solution in some countries, in others, such as northern Europe, it would make much more sense to focus on reducing the volume of wastewater. As droughts are rarely an issue in these regions, such an expensive and energy-intensive method of water purification makes little sense.
4 Another new, and perhaps more controversial, solution to the fresh water crisis is a form of weather-modification【人工影响天气】 known as cloud seeding, a technique that aims to boost rainfall by stimulating production of ice crystals in clouds. Essentially, particles of potassium chloride, sodium chloride, or silver iodide are fired into passing clouds where they attract existing water vapor. 【从本质上讲，氯化钾、氯化钠或碘化银的微粒被发射到经过的云层中，吸引现有的水蒸气。】The vapor bonds with the chemical particles to form ice crystals, which increase in size until they are too heavy to remain suspended and fall, often melting on the way to form rain. 【水蒸气与化学粒子结合形成冰晶，冰晶体积不断增大，直到重到无法悬浮下落，常常在形成雨的过程中融化。】Cloud seeding can also be used to dissipate【驱散】 clouds. Proponents【支持者；建议者】 argue that cloud seeding offers an inexpensive and energy-efficient alternative to desalination. In the UAE, Dr. Habib of the National Center of Meteorology and Seismology recently argued that studies suggest rain enhancement programs could increase rainfall by 10%–30% (Pennington, 2017). However, while research into cloud seeding is ongoing, the technique has garnered【获得了】 its fair share of criticism. In fact, the United States National Academy of Sciences (2003) stated that 30 years of research showed no convincing evidence that it worked. This is primarily because you cannot use the technique to actually generate clouds and it is impossible to conclusively demonstrate that the clouds that have been treated wouldn't have produced rainfall anyway. Essentially, you cannot extract moisture 【提取水分】from the air if it isn't there to begin with, meaning the technique simply isn't viable on cloudless days or during periods of drought.
5 One final solution is to reduce water consumption in the manufacturing sector. In the US, just under 5% of fresh water is used in the production of consumer goods, usually as a coolant or cleaning agent.【通常用作冷却剂或清洗剂】 This may sound like a fairly insignificant percentage, but the volume of water it equates to is staggering—for example, the United States Environmental Protection Agency estimates that it takes 39,090 gallons of water to manufacture a single car. One way to reduce consumption is to seek alternative sterilization methods【消毒方法】 such as CO2 cleaning, which uses CO2 recycled from other industries in place of water to allow for【使……成为可能】 "dry-cleaning in an eco-friendly manner" (Wikstrom, 2015). While CO2 cleaning has been used for decades in the aerospace and automotive industries, it has unfortunately not been rolled out to the manufacturing sector as a whole. Another way to reduce the industrial water footprint is to recycle more. It's estimated that recycling just one newspaper saves around 3.5 gallons of water. Buying second-hand clothes would also help because, for example, it takes over 100 gallons of water to produce a single cotton T-shirt.
6 Global water consumption has reached unsustainable levels. If we do not modify our behavior, billions of people will be plagued【困扰；折磨】 by water scarcity. To put it simply, fresh water shortages are likely to cause the next great global crisis. In the words of Jean Chrétien, former Canadian prime minister and co-chair of the InterAction Council, "The future political impact of water scarcity may be devastating … using water the way we have [done] in the past simply will not sustain humanity in future."
1. Why does the world's population still face water scarcity even though water covers most of the Earth's surface?
Although most of our planet is covered by water, only 3% of it is drinkable fresh water. Of the fresh water, 99% is inaccessible as it is buried beneath the world's glaciers. As the world's population is growing rapidly, coupled with the growth of water consumption in agriculture and manufacturing, the fresh water supply has reached an unsustainable level. Thus, the world's population is still facing water scarcity.
2. Why may the solution of switching to a vegetarian or vegan diet not be viable?
It is true that switching to a vegetarian or vegan diet can reduce water consumption, as the production of meat is much more water-intensive than the production of vegetables. However, asking people to consume less (or no) meat means asking them to significantly change their dietary habits or even culture. As most of the population in almost all countries are not vegetarians, the feasibility of switching dietary habits is doubtful.
3. Can desalination be applied widely to address water shortage issues? Why or why not?
Desalination cannot be applied widely to address water shortage issues, at least not right now. First, desalination is a capital-intensive process, meaning that it costs lots of money. When a place cannot afford it financially, even if this place is located in coastal areas, desalination is not a viable option. Second, desalination is fairly inefficient. The water produced by 18,426 desalination plants around the world can only meet the needs of 1% of the world's population. Therefore, desalination can only be applied in certain areas where there is a balance between investments and rewards.
4. Based on the text, what are the major ways of reducing water consumption in manufacturing?
The author mainly mentions two ways to reduce water consumption in the manufacturing sector. One way is to use alternative sterilization methods, such as carbon dioxide cleaning. This will save water and make sterilization more eco-friendly. The second way is to recycle more. Recycling more products means that few new products will be produced, and thus less water will be consumed.
5. How does the author increase the persuasiveness of this article?
The author uses a number of strategies to increase the persuasiveness of this article. First, the author mainly explains from a third-person perspective. By avoiding using first-person perspective often, third-person perspective increases the objectivity of the whole article. Second, the author uses statistics and research to support major arguments. By appealing to logic, the author makes these arguments more convincing. Third, the author uses language cautiously and precisely and does not oversimplify or overgeneralize problems and solutions. For example, in the sentence "While desalination is arguably a necessary solution in some countries …," the adverb "arguably" is a hedging word, showing that the author uses words cautiously and does not oversimplify the solution.
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