People are making more and more demands for the world's natural resources. If babies born in 1991 live for80 years, the human population of the world may be anything from twice to three times the present total by 2070. In other words, they will have to share what is left of the earth's resources with between 10 and 15 billion other people. But hopefully there will be a significant decrease in the growth of population. What if this does not happen?The answer is that before the babies born in 1991 reach the age of 40 they will have been sharing resources with as many as 10 billion other people. Limiting the pollution of water and the atmosphere, controlling the output of the chemicals that may be causing global warming,and eating less meat may go some way to help, but can anyone seriously imagine that these are going to solve the problems of the "baby class" of 1991? There is no getting away from the fact that people are responsible for the present state of the world, and only people can solve the problems. The decisions have to be taken by people as members of national and local governments; as leaders and decision-makers in industry; as scientists and technologists; as professional engineers and designers; as religious leaders and as individual citizens.