人们需要水来饮用、种植粮食和清洁身体,工业也需要大量用水。用水量一直在增加——20世纪,全世界人口增加了两倍,而用水量则增加了六倍。随着生活水平的提高,人们需要更加洁净的生活环境,吃种类更加丰富的食物(这就导致越来越密集的农业种植),所有这些会需要更多的水。我们已经将河水、溪水和湖水中的水用去了一半,但是野生动物和植物也 People need water for drinking, growing food and cleaning their bodies. Industry also needs a lot of water. Water usage has been increasing - in the 20th century, the world’s population tripled and water consumption increased sixfold. As living standards rise, people need cleaner living conditions and eating more kinds of food (which leads to more and more intensive farming), all of which will require more water. We’ve already cut in half the water in streams, streams and lakes, but wildlife and plants also