As an old saying goes, “Water is life.” It shows that water is vital for human beings and it is a necessity in our life. However, nowadays, water is becoming the new oil: a resource long squandered and becoming scarcer.

    First of all, due to the sheer number of people using water, a water crisis is near. Sixty years ago, the world’s population was about 2.5 billion. Today there are about 7 billion. By 2050 the number could hit 9 billion.

    Farmers’ increasing demand for water is caused by people’s desire for better-tasting, more interesting food. With 2 billion people around the world about to enter the middle class, the agricultural demand for water will increase, even if the population stops growing.

    What’ more, industry also needs water. Together, the demands by industry and domestic activities quadrupled in the second half of the 20th century, growing twice as fast as those of farming.We also should realize that the supply of water is finite, which makes it difficult to meet demand. Because of the law of conservation of mass, you can neither destroy water nor readily make it.

    Most of Earth’s surface is sea. As a result, over 97 percent of the water of the total on Earth is saltwater. Though we can change seawater into fresh water, desalination is expensive and uses lots of energy. What’s worse, of the 2.5 percent of water that is freshwater, about 70 percent is frozen, either at the poles, in glaciers or in permafrost.

    In principle, water is not evenly distributed. Just nine countries have 60 percent of all available fresh water. Some countries have an abundance of water, while others with a large population have little.

    Even within countries, the variations may be huge. For example, the average annual rainfall in India’s northeast is 110 times that in its western desert. Besides, in some places with far too much water, flooding is common.

    In addition to the uneven distribution, because water is heavy, it is difficult and expensive to transport it with artificial diversion.

    Furthermore, almost anywhere arid, the water underground, once largely ignored, has come to be seen as especially valuable as the demands of farmers have outgrown their supply of rain and surface water. In many places, the quantities being withdrawn exceed the amount that forms, resulting in water shortages all over the world.

    In the end, a widespread belief that no one should have to pay for water makes people take it for granted that we can use water as we like.

    A water crisis is approaching, and we should not only realize the cause of the water shortage but seek ways to save water.