Half of the world’s population now lives in towns.
Very rapid urban growth is predicted for the next two decades, 95% of which will take place in developing countries because of the combined effects of rural exodus and demographics. This rapid growth of cities in the South represents one of the global challenges which humanity will have to address in the 21st century, with major consequences for the world’s social, economic and environmental balance.
Cities will also combat climate change, through both adaptation and mitigation. Development will thus be an urban challenge in the future in cities which will become the centre of all paradoxes, where difficulties will be concentrated but also hopes.