China's water problem Although two thirds of the earth is covered with water, 97.5% of it is salt water, and 87% of the remaining 2.5% fresh water is polar ice sheets, glaciers and ice and snow that are difficult for human beings to use. The fresh water available to human beings only accounts for 0.26% of the global total water, and most of these fresh water is groundwater. In fact, the fresh water that humans can get from rivers and lakes only accounts for 0.0 14% of the total water. For example, there is only one tablespoon of fresh water available in the earth's big water tank, and this tablespoon of water has been seriously polluted. According to United Nations statistics, since the beginning of the 20th century, the global consumption of fresh water has increased by about 6-7 times, which is twice the population growth rate. At present, 1 400 million people in the world lack safe and clean drinking water, that is, on average,1person in every five people is short of water. It is estimated that by 2025, 3 billion people in the world will be short of water. More than 40 countries and regions are affected, mainly in Africa and the Middle East, and parts of India, Peru, Britain, Poland and China will also be affected. China is one of 13 water-deficient countries in the world. According to the internationally accepted standards, the per capita water resource of 2000 cubic meters is the edge of serious water shortage, and the per capita water resource 1000 cubic meters is the minimum requirement line. By 2030, China will. At present, the surface water that can't be drunk due to pollution accounts for 40% of all monitored water bodies in China, 78% of river sections flowing through cities are not suitable for drinking water sources, 50% of groundwater is polluted, and 64% of people are using unqualified water sources. According to the inspection results of about 700 large and medium-sized rivers in China by the water conservancy department, nearly 10/2 of the existing rivers in China have been polluted, among which110 has been seriously polluted for a long time, which makes the above water shortage worse. Due to serious pollution, at present, the river water of half tributaries in the upper reaches of Huaihe River has completely lost its use value, and 62.5% of the main stream cannot be used at all in dry season. The Pearl River, which accounts for 0/2% of the national water resources, is also short of water due to pollution, and many rivers are black and smelly. The water quality in the urban reach of Guangzhou is worse than the five standards, and the river water contains more than 20 kinds of toxic substances. As a result, Guangzhou was forced to spend huge sums of money to transfer water from Xijiang and Dongjiang rivers dozens of kilometers away. Since 1990s, the sewage discharge in the Yangtze River basin has been increasing day by day, with an average of about 654.38+042 billion cubic meters per year, accounting for 40% of the national annual sewage discharge. Shanghai's water intake extends from Huangpu River to the center of the Yangtze River. Like air, water is necessary for people and all living things. People can't live without water, and animals and plants can't live without water. Scientists have long confirmed that early primitive life originated from water. Therefore, we can say that water is the source of life. In nature, oceans, rivers, lakes, glaciers and groundwater constitute a water world, which scientists call hydrosphere. Hydrosphere and atmosphere, lithosphere and biosphere are isomorphic, forming a complete world.