Introduction Although the world is large, man is able to live in only a small part of it. The atmosphere is only about eleven kilometers thick. The soil that supplies us with food is only about fifteen centimeters thick and man can live on only about one eighth of the worlds surface. In the past two hundred years man has greatly changed his environment. Water has been given to deserts. Roads have been built across deserts and through forests Cities have grown to an astonishing size. many scientists think that man may not find life pleasant in the world of the futureIntroduction Although the world is large, man is able to live in only a small part of it. The atmosphere is only about eleven kilometers thick. The soil that supplies us with food is only about fifteen centimeters thick and man can live on only about one eighth of the world’s surface. In the past two hundred years man has greatly changed his environment. Water has been given to deserts. Roads have been built across deserts and through forests. Cities have grown to an astonishing size. Many scientists think that man may not find life pleasant in the world of the future