What are the negative effects of urbanization

Urbanization and sustainable development

More and more people around the world are living in cities. The ratio of urban to rural population is reversed within a century. While 30 percent of the world's population lived in cities in 1950, it is expected to rise to 66 percent by 2050. Growth will primarily take place in emerging and developing countries, but it will have enormous effects worldwide, including on Western societies. This is indicated by the WBGU, the German Advisory Council on Global Change, among others. The advisory board published an expert report on urbanization in 2016.

The pattern of urbanization that is common today is not sustainable. Among other things, it brings with it consumption and production patterns that endanger natural resources. For example, cities already account for 70 percent of global CO2Emissions responsible. At the same time, urbanization has positive aspects. "Our struggle for global sustainable development will be won or lost in the cities," said United Nations Secretary General Ban Ki-moon.

The development of the cities depends on how their growth is planned and controlled, according to the United Nations World Cities Report of 2016. At the UN Habitat III conference in October 2016, the member states adopted the so-called "New Urban Agenda" adopted. This document defines a framework and formulates goals for the sustainable development of cities.

Urbanization worldwide: terms, trends, key facts

On the one hand, urbanization refers to the degree of "urbanization", that is, the proportion of the population that lives in urban areas. On the other hand, urbanization describes the increase in the urban population. Causes are migration from rural to urban areas or population growth within cities.

For the first time in 2007, the number of people living in cities worldwide exceeded that of the rural population. Before that, the rural population was always in the majority. Especially from 1950 onwards there was a global trend towards urbanization. While in 1950 30 percent of people lived in cities, in 2014 it was already 54 percent. In 2050, two-thirds of the population - 66 percent - are expected to live in cities. The majority ratio of urban and rural populations will thus be reversed within 100 years.

The urban population has also grown rapidly in absolute terms. In 1950 it was 746 million, in 2014 it was 3.9 billion people. It is expected to grow by a further 2.5 billion people by 2050.

There are clear regional differences in urban growth. The affluent countries have had a high degree of urbanization for decades. But since the 1950s, urbanization has been particularly rapid in emerging countries. In 1950 the proportion of the urban population in affluent countries was 57 percent, in emerging countries only 20 percent. In 2014 it was 80 percent in affluent countries, and 63 percent in developing and emerging countries. The proportion there is expected to rise to 79 percent by 2050.

The majority of city dwellers (53 percent) already live in Asia today. Almost 90 percent of the growth by 2050 will take place in Asia and Africa.

What is a city

When calculating the proportion of the urban and rural population, the United Nations bases its calculations on the definitions and figures provided by the respective countries. There is no globally standardized definition for the terms urban and rural areas. There are also no uniform size classes or a uniform division into small, medium-sized or large cities. The WBGU points out that, among other things, this means that the United Nations' calculations contain considerable imprecision.

In Germany, the Federal Institute for Building, Urban and Spatial Research (BBSR) differentiates between rural communities, small towns (5,000 to 20,000 inhabitants), medium-sized towns (20,000 to less than 100,000 inhabitants) and large cities (at least 100,000 inhabitants). In order to distinguish between urban and rural areas, the population density and the proportion of settlement areas are compared. In addition to key figures, the meaning is also important: cities are centers that gather special functions in one place. They are of particular political, cultural and economic importance. They serve, for example, as production facilities or trading hubs.

In its publications on global urbanization, the United Nations distinguishes between smaller cities (up to 500,000 inhabitants), cities (500,000 to 1 million inhabitants), medium-sized cities (1 to 5 million), large cities (5 to ten million) and Megacities or megacities (more than ten million)

Megacities are therefore significant due to their size and concentration of economic power, but they only accommodate around one eighth of the world's population. However, the development of the megacities reflects the trends in urbanization. In 1990 there were only 10 cities worldwide with more than 10 million inhabitants; in 2014 there were already 28. Most megacities and large cities are to be found in the global south. There are six megacities in China alone. In Asia and Africa, the number of megacities, large cities and the proportion of people living there will increase sharply.

What are the reasons for urbanization?

The reasons for urban growth are either natural growth or immigration from rural areas. Natural growth is the growth that results from the surplus birth rate of the urban population. In addition, urban areas can expand into previously rural areas, or rural areas condense and are reclassified as urban areas.

Depending on the city, region and time period, different reasons can be responsible for the growth. In developing countries, natural growth has the largest share in urban growth (60 percent).

Urbanization as a challenge for sustainable development

Where people live has a decisive influence on their lifestyle - including employment, consumption patterns, education, their supply of living space, water, sanitation and health care. Their ecological footprint is also related to this, as is the risk of natural disasters.

Just a few decades ago, the largest urban settlements were to be found in the industrialized countries. Today they are predominantly in developing and emerging countries. The fastest growing cities worldwide are in Asia and Africa and typically have 500,000 to five million inhabitants.

Rapid and uncontrolled growth is usually incompatible with the goal of sustainable development, especially when the necessary infrastructure is lacking or there are no provisions to ensure that the benefits of urban development are available to all. In 2012, around a third of the urban population in developing countries (around 860 million people) lived in slums or informal settlements. There is a lack of adequate housing or there is overpopulation. There is also a lack of sanitary facilities and a safe water supply. In many places the slum population has to expect displacement.

In some cities, the unplanned or insufficiently controlled growth leads to rapid expansion in the area and environmental pollution.

Today, the land consumption of cities is growing twice as fast as their population. This is problematic, for example, where development competes with agriculture. In the Cairo area in Egypt, for example, informal settlements are growing on areas that could also be used for agriculture. But such areas are rare, because the city is surrounded by desert areas.

Environmental problems arise both in the city itself and in the region. In addition, there are some global interactions, for example greenhouse gas emissions contribute to climate change.

Typical local and regional environmental impacts include air pollution, overuse of water supplies and water pollution, noise and pollution.

An extreme example of a problematic water supply is the Peruvian capital Lima. The region is characterized by a dry climate, so that the city is almost completely dependent on the glacier water from the Andes.

In many large cities in emerging and developing countries there are deficiencies in waste and wastewater disposal. In the Indian megacity of Mumbai, for example, only 42 percent of the population is connected to the sewage system. In the slums it is only 2 percent. Therefore, the waters in the region are heavily polluted.

The Chinese capital Beijing is known for extreme air pollution. The values ​​measured there often exceed the limit value recommendations of the World Health Organization many times over. The causes are traffic and industrial emissions.

At the same time, cities open up the opportunity to offer the population better access to public services and better supply. Health care or access to education for large numbers of people can be achieved more efficiently in the city. Local public transport, living space, energy and water supply can be organized in a more cost-effective and environmentally friendly way in densely populated areas. The urban population usually has access to a larger and more diverse job market. Overall, she can lead healthier lives, according to the United Nations.

Approaches to sustainable urbanization

Cities are so complex and different that there are no transferable recipes for planning and managing cities, according to the WBGU. The respective local conditions must be taken into account in order to find individual solutions for sustainable development. This includes the respective decision-makers as well as the population. In addition, the cities' competence to act must be promoted, according to the WBGU.

The advisory board also summarizes the requirements for sustainable urbanization. These include:

  • The infrastructures for energy, water, waste, mobility and the buildings have to be rebuilt. The conversion must take place in a climate-friendly manner, and the goal must be to avoid future greenhouse gas emissions. This is often referred to as "decarbonisation". This means, for example, that the energy supply will be switched to renewable energies. In the mobility sector, it is necessary to move away from the focus on motorized individual transport.
  • Cities should be environmentally friendly and offer healthy living spaces. For example, urban air and water pollution problems need to be resolved. In addition, the environmentally friendly handling of waste must be ensured.
  • People's quality of life must be ensured. This area goes beyond urban design and infrastructure development. The WGBU points out that quality of life does not only depend on income. The subjective well-being must be given more attention. The spatial design, which is based on “human dimensions”, plays an important role. Among other things, the city must offer recreational spaces and enable social interaction. This also raises the question of how people can help shape urbanization processes.

The efforts in the Danish capital, Copenhagen, are often cited as an example of human-centered, sustainable urban planning. One of the goals of Copenhagen is to become climate neutral by 2025. The energy supply is ensured by means of renewable energies, and remaining greenhouse gas emissions are to be offset.

Copenhagen has turned away from auto-centered traffic planning. The city is particularly known for innovations and experiments to promote cycling. There is a very well developed network of cycle paths. Bicycle traffic often has priority over other means of transport, for example with a “green wave” for bicycles. The city has developed an integrated mobility system that is designed to make it easier to switch between different types of public transport.

There are also various approaches to political participation. They range from legally stipulated opportunities to participate in urban development to informal, creative processes. For example, households are asked about urban development issues.

Related Links

Scientific Advisory Council of the Federal Government - Global Change (WBGU): The Movement of Mankind: The Transformative Power of Cities

Federal Foreign Office: Sustainable Urbanization (2016)

Federal Environment Agency (UBA): Fine dust in megacities (2013)

National urban development policy: German contribution to the "New Urban Agenda" of the United Nations

United Nations Habitat: World Cities Report (2016, in English)

United Nations, Department of Economic and Social Affairs: World Urbanization Prospects (2014, in English): Highlights

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