根据世界银行的统计，多达20亿人缺乏足够的卫生设施来保护他们免受水传播疾病的侵害，而10亿人完全无法获得洁净水。根据宣布2005-2015为“生命之水”十年的联合国，世界上95％的城市仍将未经处理的污水倾倒入供水系统。因此，毫不奇怪，发展中国家80％的健康疾病都可以追溯到不卫生的水源。 1998年出版的“最后绿洲：面临水资源短缺”一书的作者桑德拉·波斯特尔（Sandra Postel）预测，由于所谓的“水资源紧张”国家的人口在未来30年内增长了六倍，因此水资源供应问题严重。 “它提出了大量关于水和农业的问题，种植了足够的食物，满足了人们在收入增加时所需的所有物质需求，并提供饮用水，”Postel说。发达国家也不能免受淡水问题的影响。自1900年以来，研究人员发现，美国的用水量增加了六倍，人口规模仅增加了两倍。这种趋势反映了生活水平提高与用水量增加之间的联系，并强调了更加可持续管理的必要性。即使在较发达的社会中也使用水供应。预计到本世纪中叶世界人口将超过90亿，解决水资源短缺问题的办法并不容易。一些人建议，技术 – 如大型海水淡化厂 – 可以产生更多的淡水供世界使用。但环保主义者认为，耗尽海水是没有答案的，只会造成其他大问题。无论如何，正在进行改进海水淡化技术的研究和开发，特别是在沙特阿拉伯，以色列和日本。世界上大约120个国家已经有大约11,000个海水淡化厂。其他人认为，将市场原则应用于水将有助于更有效地分配供应。例如，哈佛中东水利工程的分析师主张为淡水分配货币价值，而不是将其视为免费的天然商品。他们说这种做法有助于缓解水资源短缺造成的政治和安全紧张局势。作为个体，我们都可以控制自己的用水量，以帮助保护正在变得越来越宝贵的资源。在干旱时期，我们可以推迟给草坪浇水。当它下雨时，我们可以在桶中收集排水，以喂养花园软管和洒水器。我们可以在刷牙或刮胡子时关掉水龙头，并采用更短的淋浴。正如桑德拉·波斯特尔（Sandra Postel）总结的那样，“少花钱多办事是迈向水安全的第一步也是最简单的一步。”
英国曼彻斯特大学环境学Assignment代写：全球供水量
According to the World Bank, as many as 2 billion people lack adequate sanitation to protect them from water-borne diseases, and 1 billion people have no access to clean water. According to the United Nations, which declared 2005-2015 as the “Water for Life” decade, 95% of the world’s cities still dump untreated sewage into the water supply system. Therefore, it is no surprise that 80% of health diseases in developing countries can be traced back to unsanitary water sources. Sandra Postel, author of the book “The Last Oasis: Facing Water Shortages,” published in 1998, predicts that the population of so-called “water stress” countries will grow six-fold in the next 30 years, Therefore, the water supply problem is serious. “It raises a lot of questions about water and agriculture, planting enough food to meet all the material needs that people need to increase their income, and provide drinking water,” says Postel. Developed countries are also not immune to the impact of freshwater issues. Since 1900, researchers have found that water use in the United States has increased six-fold and the population has only tripled. This trend reflects the link between improved living standards and increased water use and highlights the need for more sustainable management. Water supply is used even in more developed societies. It is estimated that by the middle of this century, the world population will exceed 9 billion, and it is not easy to solve the problem of water shortage. Some people suggest that technology – such as large desalination plants – can produce more fresh water for the world to use. But environmentalists believe that there is no answer to the exhaustion of seawater, and it will only cause other big problems. In any case, research and development to improve desalination technologies is underway, especially in Saudi Arabia, Israel and Japan. There are approximately 11,000 desalination plants in approximately 120 countries around the world. Others believe that applying market principles to water will help allocate supplies more efficiently. For example, analysts at Harvard Middle East Water Engineering advocate the allocation of monetary value to freshwater, rather than treating it as a free natural commodity. They say this approach helps alleviate the political and security tensions caused by water shortages. As individuals, we can control our water consumption to help protect resources that are becoming more and more valuable. During the dry period, we can postpone watering the lawn. When it rains, we can collect drainage in the bucket to feed the garden hose and sprinkler. We can turn off the faucet and use a shorter shower when brushing or shaving. As Sandra Postel concludes, “doing more with less is the first and easiest step towards water