Since 2007, more people live in cities than in rural areas, and the trend continues. According to UN forecasts, in 20 years more than 70 % of the world’s population will live in cities. While in 1800 there were only three cities in the world with more than one million inhabitants – London, Beijing, and Tokyo – now there are around 450 cities with a population of over a million.
Megacities - a new Challenge
Cities are termed “megacities” or “urban agglomerations” if they have more than five, eight, or ten million people, depending on the study. A distinction is made between three types of cities: emerging cities, transitional cities, and mature cities. The strongest megacity growth can currently be found in Asia and Latin America: Seoul, Mumbai, Manila, Jakarta, Bangkok, Delhi, Shanghai, Calcutta, and Dhaka are booming, as are Sao Paulo, Buenos Aires, and Rio de Janeiro, to name but a few.
Each of these megacities is facing individual and regional challenges. Still, certain issues can be identified that are relevant to all megacities, enabling them to bring their competitiveness, living quality, and ecological sustainability into sync. They all bundle trade, culture, knowledge, and industry, and often make a disproportionately high contribution to the gross domestic product (GDP). For example, Tokyo, Mexico City, and Buenos Aires achieve 40 to 45 % of their country’s respective GDP, and in Dhaka and Bangladesh the figure is even higher, at 60 %*. In all megacities, mobility and transport infrastructure play an important role. While sustainability and environmental protection are normally very important, economic aspects are the top priority in developing countries. The biggest problems facing megacities worldwide are unemployment, security, energy, water, air pollution, and traffic. New concepts, new technologies, and urban ideas can help strike a balance between competitiveness, quality of life, and environmental protection, and preserve them in the long term.