We are experiencing a historical transition – human civilization will more and more coalesce into very large urban centers. Cities are the manifestation of the cultural, economic and social acceleration that we have experienced in the last century. In 1950 about 2/3 of the population worldwide lived in rural areas, and 1/3 in urban settlements. By 2050, we will roughly see the reverse distribution, with more than 6 billion people living in the crowded environment of urbanized areas. Nearly all global population growth from 2017 to 2030 will be absorbed by cities, and we expect about 1.1 billion new urbanites over the next 13 years.

Urbanization is not a new phenomenon, but the process took on a whole new dimension in the 20th century. We are witnessing a historic transformation of human social roots on a global scale. Ancient rural cultures are replaced by the complex environments of diverse megacities, with millions of inhabitants. The first major change in settlement patterns was the accumulation of hunter-gatherers into villages many thousand years ago. Village culture is characterized by common bloodlines, intimate relationships, and communal behavior. Urban culture is characterized by distant bloodlines, unfamiliar relations, and competitive behavior. Your neighbors are strangers, and there are millions of them. This unprecedented movement of people will continue and even intensify during the first half of the 21st century. The emerging “metroplexes” (conglomerates of cities) will grow to sizes unthinkable only a century ago.

Urban areas currently occupy less than 5% of the world’s landmass ¹. Nevertheless, they account for around 70% of both global energy consumption and greenhouse gas emission. Innovation in urban infrastructure and technology is essential for achieving sustainable growth in the future. ²

Planning decisions and strategic design in the context of rapidly increasing urbanization will decide the future of countries, of regions and large social systems. The global political order of the future will depend on whether we get this right or not. The design of cities and urban areas influences social equality, mobility, quality of life, eduction, global competitiveness, and energy-efficiency.

Cities grow not only by numbers but also in size. In fact, city areas grow faster than city populations and affect environmental sustainability at local, regional and global scales. How we manage this unprecedented urban growth in the following years strongly influence the outcome of our efforts to achieve worldwide sustainability.

Between now and 2050, 90% of the expected increase in the world’s urban population will take place in the urban areas of Africa and Asia ³ The projected urban growth will mostly affect the developing world. In these countries, however, the correlation between the rate of urbanization and economic growth is weaker, which means that the growth of urban areas translates into the creation of slums. Future urban population growth will take place in small- to medium-sized urban areas in developing countries. These urban areas will geographically expand on average twice as fast as the urban population growth, which will have significant consequences for greenhouse gas emissions and climate change.

Here are some highlights from the United Nations World Population Prospects, 2015:

• Globally, more people live in urban areas than in rural areas, with 54% of the world’s population residing in urban areas in 2014. In 1950, 30% of the world’s population was urban, and by 2050, 66% of the world’s population is projected to be urban.

• Today, the most urbanized regions include Northern America (82% living in urban areas in 2014), Latin America and the Caribbean (80 percent), and Europe (73%). In contrast, Africa and Asia remain mostly rural, with 40 and 48 percent of their respective populations living in urban areas.

• All regions are expected to urbanize further over the coming decades. Africa and Asia are urbanizing faster than the other regions and are projected to become 56 and 64% urban, respectively, by 2050.

• The rural population of the world has grown slowly since 1950 and is expected to reach its peak in a few years. The global rural population is now close to 3.4 billion and is expected to decline to 3.2 billion by 2050. Africa and Asia are home to nearly 90% of the world’s rural population. India has the largest rural population (857 million), followed by China (635 million).

• The urban population of the world has grown rapidly since 1950, from 746 million to 3.9 billion in 2014. Asia, despite its lower level of urbanization, is home to 53% of the world’s urban population, followed by Europe (14 per cent) and Latin-America and the Caribbean (13%).

• Continuing population growth and urbanization is projected to add 2.5 billion people to the world’s urban population by 2050, with nearly 90% of the increase concentrated in Asia and Africa.

• Just three countries—India, China, and Nigeria—together are expected to account for 37% of the projected growth of the world’s urban population between 2014 and 2050. India is projected to add 404 million urban dwellers, China 292 million and Nigeria 212 million.

• Close to half of the world’s urban dwellers reside in relatively small settlements of less than 500,000 inhabitants, while only around one in eight live in the 28 mega-cities with more than 10 million inhabitants.

• Tokyo is today the world’s largest city with an agglomeration of 38 million inhabitants, followed by Delhi with 25 million, Shanghai with 23 million, and Mexico City, Mumbai and São Paulo, each with around 21 million inhabitants. By 2030, the world is projected to have 41 mega-cities with more than 10 million inhabitants. Tokyo is projected to remain the world’s largest city in 2030 with 37 million inhabitants, followed closely by Delhi, where the population is projected to rise swiftly to 36 million.

• Several decades ago most of the world’s largest urban agglomerations were found in the more developed regions, but today’s large cities are concentrated in the global South. The fastest-growing urban agglomerations are medium-sized cities and cities with less than 1 million inhabitants located in Asia and Africa.

• Some cities have experienced population decline in recent years. Most of these are located in the low-fertility countries of Asia and Europe where the overall population is stagnant or declining. Economic contraction and natural disasters have contributed to population losses in some cities as well.

• As the world continues to urbanize, sustainable development challenges will be increasingly concentrated in cities, particularly in the lower-middle-income countries where the pace of urbanization is fastest. Integrated policies to improve the lives of both urban and rural dwellers are needed.

Notes:

1. Sustainable Urbanization Policy Brief

2. For instance, greenhouse gas emissions could be reduced substantially through transformative change in the transport systems of the world’s largest cities.

3. United Nations, Department of Economic and Social Affairs, Population Division (2014). World Urbanization Prospects: The 2014 Revision, Highlights.