How will cities need to change to accomodate growth

Cities will need to grow vertically, to become much more self-sustaining

Explanation:

Cities will need to grow vertically and to become much more self-sustaining. The global population is growing and it is predicted to grow at least until the end of this century. Even more so, the population of cities is growing at an even faster rate, with people abandoning rural areas and towns and moving into the large urban areas.