According to UN figures, today’s urban population of 3.2 billion will rise to nearly 5 billion by 2030. Three out of five people will then live in cities.
Three-quarters of the population of industrial countries, approximately 900 million people, already live in cities– over the next fifteen years this figure will only increase slightly. However in the developing and emerging countries of Africa and Asia, there will be an enormous increase: about 60% of the total population – more than 3.8 billion people – will be living in cities by 2025 . Strong population growth, intensive industrialization and globalization processes and the attraction of economically prosperous cities and rural flight will cause cities to grow. Alongside the demographic change and global ageing, the impact on the affected societies will be huge. Urban economies are increasingly being integrated into international divisions of labor and economic linkages. Millions of people need housing, an infrastructure and secure access to food, water, healthcare and energy.
In the next ten years the world will have about 500 cities with more than one million inhabitants. The majority of people will live in metropolises of up to five million inhabitants. The number of cities with over five million people, currently there are 50 cities, as well as those with more than ten million people, 21 megacities as of 2011, will also continue to grow.
Megacities are disproportionately affected by environmental contamination, congestion, consumption of resources, natural disasters, water shortages, economic crises and religious disputes. But they are also sowing the seeds for sustainable developments, because of the reduced consumption of land, as cities usually expand vertically, the resources can be used more efficiently and through improvements in education and healthcare, more people can be reached.
Technical innovation is more viable in megacities and can be more efficiently integrated into existing structures such as transportation systems, power networks, process innovation and buildings with higher energy efficiency.