The world population is expected to be between 9 and 10 billion people by 2050, compared to 7 billion today. The increase will be distributed in the giant cities or in the multitude of cities of more than a million inhabitants. The sustainable management of the environment of these large urban spaces is one of the greatest challenges of the 21st century.
By 2050, 66% of the world’s population could live in cities, up from 54% in 2014 and 30% in 1950, according to the UN report on the prospects for urbanization.
The cities of the future
In 35 years, an additional 2.5 billion people will populate urban areas. This increase is equivalent to the creation of 70 cities with more than one million inhabitants each year by 2050.
About 90% of this increase should be in Africa and Asia, which are now mostly rural continents, and less developed. India, China and Nigeria will be the three most affected countries. Agglomerations in the Americas and Europe – now by far the most urbanized continents – will experience a moderate increase.
The “megacities” of the world (called when they exceed 10 million inhabitants), led by Tokyo, New Delhi, Shanghai, Mexico City, Mumbai (Bombay) and São Paulo, will continue to grow as there will be more than 40 in 2030; compared to 28 in 2016.
Against this background, the management of the city of the future has become a major development challenge in the 21st century. Engineering companies like CAYCCA speak of two factors that accentuate it:
- Urbanization is extreme in developing countries where infrastructure problems are most acute. Housing is often precarious. Treatment of sewage and waste is generally insufficient and transportation is congested.
- Unbridled urbanization occurs when the planet faces the consequences of climate change, and problems are likely to accumulate. Extreme weather events, risks to food and health, the fragility of estuarine areas make urban management more complex.
The UN speaks of sustainable development as that which aims to make compatible -in the long term- the demands of the environment, economic development and social progress.
Applied to cities, sustainability involves the environment. It concerns both air pollution, which reaches catastrophic dimensions in China, and water supply and treatment, a major problem in Cairo, for example, sanitation and waste treatment.
With climate demands, cities are increasingly concerned about their CO2 emissions. Some like Copenhagen ultimately point to the rather theoretical term “carbon neutrality”.
The use of renewable energy, the renovation of houses, the reduction of car traffic are the essential tools of these policies, which are increasingly led by public and private associations.
In Europe, cities, even if they experience less spectacular development than in Africa or Asia, are programmed to continue to grow with the evolution of modes of exchange and production.
But this problem of advanced urbanization must necessarily take into account the other great phenomenon of this new century: climate change. How to combine the growth of the population in small spaces with the need to fight against environmental degradation?
Several tracks are explored and will no doubt be complementary. The most interesting thing concerns energy efficiency. While sprawling cities are a major source of anthropogenic CO2 emissions, they are also an essential part of the solution by allowing solutions to go global.