Imagine you are transported to the year 2050: the same city, but a different time. Look around at a city that has changed completely. Between the buildings are grasslands and lakes. Suburbs in the distance are overgrown with trees in huge swathes of forest. And it’s all eerily quiet – the noise of traffic that once filled the streets and rumbled out to the suburbs has ceased.
This will probably be a real scenario soon enough for large parts of the world’s population, and some of the changes are already being made. Today some 55% of the world’s 8 billion people live in cities. By 2050 it will be 68%, according to the UN, with cities accommodating 2.5 billion more people than they do now.
This brings challenges. Living conditions in cities deteriorate as numbers rise, while rising
