The world population is expected to rise from 7 billion today to 9 to 10 billion people by 2050. Growth will be spread across the large metropolises and the many cities that have over one million inhabitants. Sustainable development of these major urban areas is one of the key challenges of the 21st century.
By 2050, 66% of the world's population is expected to live in cities, versus 54% in 2014 and 30% in 1950, according to the the World Urbanization Prospects report published by the United Nations in 20141.
What this means is that in 35 years, 2.5 billion more people will be living in urban areas. This would be equivalent to creating 70 cities with more than one million inhabitants every year until 2050. About 90% of the growth is expected to take place in Africa and Asia, which are still largely rural and underdeveloped. The countries most affected will be India, China and Nigeria. Cities in Europe and the Americas, by far the most urbanized continents, will experience moderate increases.
The number of megacities with a population of over 10 million – such as Tokyo, New Delhi, Shanghai, Mexico City, Mumbai and Sao Paulo – will continue to grow. From 2016 to 2030, their number is expect to rise from 28 to more than 40. Intermediate-sized cities will be concerned as well. At present, nearly half of the world's urban population already lives in cities with less than 500,000 inhabitants. The sharpest growth will take place in cities that have between 500,000 and 1 million inhabitants.
2.5 billion: the number of additional city dwellers in 2050
How to manage the city of the future has become a key development challenge of the 21st century. Two factors are adding to the difficulty of the challenge:
- Extreme urbanization in the developing world, where infrastructure problems are the most dire. Precarious housing is widespread. According to the World Economic Forum's 2015 global risks report, "40% of the world's urban expansion is taking place in slums”2. Furthermore, waste and wastewater treatment tends to be inadequate, and transportation congestion is common.
- Rampant urbanization, just when climate change mitigation needs to be addressed, possibly leading to multiple problems. Extreme weather conditions, which pose food supply and public health risks, as well as threats to estuaries, are making urban management more complex. On the positive side, although these rapidly expanding cities are a major source of anthropogenic carbon emissions, they are also an important key to solving the problem, since their solutions can be applied globally.
Sustainable developmentThis term was first defined in the Brundtland Report, published in 1987, as “development that meets the needs of the present without..., a concept first introduced by the United Nations, promotes the long-term balance of social, economic and environmental objectives. The exponential growth in digital technology has given rise to another popular concept – that of the smart city.
One-third of the world's inhabitants lived in urban areas in 1950, versus two-thirds in 2050.
Three Major Priority Areas
Applied to cities, sustainabilitySustainability indicates a state that is sustainable or reasonably manageable over the long term. concerns three vital sectors:
The environment - This sector covers air pollution (which has reached catastrophic levels in China); water supply and treatment (a major problem in Cairo); and waste management (woefully insufficient in Rio de Janeiro). Due to climate concerns, cities are making more and more efforts to cut their co2See Carbon Dioxid emissions. Some cities, such as Copenhagen, have their sights set on carbon neutrality, which is in fact a fairly theoretical concept. Emission-reducing strategies are based on several key initiatives aimed at promoting renewable energyEnergy sources that are naturally replenished so quickly that they can be considered inexhaustible on a human time scale..., insulating homes and reducing car use. These initiatives are increasingly being funded through public-private partnerships.
The economy - The cost and availability of energy, the quality of housing and the availability of communication resources are key competitive drivers of a city's economic attractiveness compared to other major world cities. Even though they aren't capitals, cities such as Osaka, Vancouver, Boston, Sao Paulo, Shanghai, Dubai and Casablanca are competing for investment.
Quality of Life - Health, housing and education are three areas that are highly dependent on access to energy. They are important social indicators for cities in the developing world. Cities in the industrialized world are focusing their efforts on improving quality of life, developing alternative means of transportation and creating green spaces. They are also introducing a growing number of digital services to enhance mobility and support a wide range of urban services. Technology-intensive cities are also being developed, such as Masdar City in Saudi Arabia and Songdo in South Korea.
All these innovations come with a high price tag of course. The Organization for Economic Cooperation and Development (organization for economic co-operation and development (oecd)Founded in 1960, the OECD promotes policies that will improve the economic and social well-being of people around the world...) has estimated that global infrastructure needs (energy, transportation, water, etc.) will amount to 3.5% of global GDP, or $71 trillion, by 2030.