One factor that contributes to our changing climate is our expanding population. Increasing numbers means increasing demands for space, food and power. In response, some ingenious people contributed to writing a book about solving the problem. They called it, the Vertical City.
The concept is based on a very simple notion; that we are running out of space. By as soon as 2050, there could be as many as 10 billion people on earth, 80% of whom will be living in urban areas. When you consider how much of the total amount of land on earth is unusable, how much is needed for farming and power generation, a population of 10 billion means space would be hard to come by. The theory, then, is to build upwards, instead of outwards. Instead of sprawling cities and infrastructure and urban landscapes, you have a small number of huge skyscrapers, interconnected with one another, providing all the needs of the inhabitants.