A THIRSTY WORLD G2sr05

 5. A THIRSTY WORLD

The world is not only hungry, it is also thirsty for man. This may seem strange, since nearly 75 per cent of the earth's surface is covered with water. But about 97 per cent of this is seawater, or salt water. Man can only drink and use the other 3 per cent—the fresh water that comes from rivers, lakes, underground, and other sources. And we cannot even use all of that, because some of it is in the form of icebergs and glaciers. Even worse, some of it has been polluted.

However, the need for water is increasing day by day. Only if steps are taken to deal with this problem now can we avoid a severe worldwide water shortage later on. A limited water supply would affect agriculture and industry. So we should all learn how to stop wasting water. One of the first steps is to develop ways to reuse it. Experiments have already been done in this field. Today, in most large cities, water is used only once and then flows through pipes to the sea, or into underground tanks for waste water. But it is possible to pipe water that has been used to a purifying plant. There it can be separated from waste matter and treated with chemicals so that it can be used again, just as if it were fresh from a spring.

But even if every large city purified and reused its water, there still would not be enough. Other sources would have to be found. Where could people turn to next?

The oceans seem to offer the best answer. There is plenty of water in the oceans. All that needs to be done is to remove the salt from the seawater. This process is expensive but it is already in use in many parts of the world. Research is going on to make the process cheaper. So you see, if we take these steps we'll be in no danger of drying up!