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May 31, 2007


Concentration of Population into Urban Areas and Sustainability

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Lecturer: Keisuke Hanaki, Professor at Department of Urban Engineering, The University of Tokyo

I have been specializing in urban engineering. In the past, I could focus on solving each individual pollution problem like industrial wastewater. But today, we must pay attention to various aspects including global warming, technologies and waste problems to change society. How should we deal with the environment of metropolitan areas and regional areas? How should a recycling-based society be built in each area? These questions fall into the field of urban engineering but are the issues of the society as well. Today, based on such a viewpoint, I would like to talk about my research and efforts about the problems caused by concentration of population into urban areas and hints on their solution.

Ever-increasing world's urban population

Increasing urban population is a worldwide tendency. Above all, it is remarkable in Asian developing nations. While the ratio of urban population to the total population increased from 35.9 percent in 1970 to 46.7 percent in 2000 on the world average, Asia went through more significant increase from 22.7 to 37.1 percent for the same 30 years. In India, for example, the ratio of urban population largely increased from 19.8 percent to 27.7 percent, while the national population itself significantly increased. Although China's national population has not increased greatly due to its one-child policy and migration from rural to urban area is strictly limited, the ratio of urban area more than doubled from 17.4 to 35.8 percent.

Let us see the projection of the population increase in the mega cities worldwide for 15 years starting from 2000. The world's largest city is the Tokyo metropolitan area (including Saitama, Kanagawa, Chiba, etc.). Its population is expected to increase from 26.4 million in 2000 to 27.2 million in 2015.

On the other hand, astonishing increase is projected in Dacca, Bangladesh. Its population was 12.5 million in 2000 (the ninth place in the world) but is expected to be 22.5 million in 2015, which means becoming the second largest city after Tokyo. Mumbai, India, shows significant increase from 16.1 million (the fifth place) to 22.6 million in 2015, which is almost the same level as Dacca and will become the third largest city in the world. In this projection, seven of the top-ten cities in 2015 will be occupied by Asian cities, showing population explosion is expected in Asian cities.

One of the problems caused by this sudden increase is that the speed of development of infrastructure cannot catch up the one of population explosion. Systems like transportation, water supply, sewerage and waste disposal cannot be built in one or two years. The high-speed increase in population will be a trigger for the collapse of the society's structure, exerting direct impact on people's lives. It also causes disordered state in suburbs. If people came to cities to find jobs but could not obtain good ones, they may illegally occupy houses due to the city's high house rent. In this way, the city is going to have slums, which will be a serious problem.

Concentration of population into urban areas in Japan

Let us move to the topic of population influx into cities in Japan. In 1960's, as many as 650,000 young people took "group employment" trains and migrated from regional areas to three major metropolitan areas of Tokyo, Osaka and Nagoya every year. It means a city larger than today's Utsunomiya (the capital of Tochigi Prefecture) was born every year. This phenomenon was obvious during the high economic growth period around the Tokyo Olympic Games (1964), but ceased in the period of the oil crisis, because the income gap between cities and regional areas had been narrowed by this time.

1970's was the age when each regional area promotes industries. In the bubble economy period around late 1980's and early 1990's, the population showed rising trend only in Tokyo but the trend was halted by the collapse of bubble economy. Since the late 1990's, however, the population has been heavily concentrated in Tokyo again and now it is more or less the only growing city in Japan. The fiercer competition becomes, the even stronger a strong city becomes - it is thought to be a positive cycle.

If we look at the Gini coefficient, or a measure of inequality of income distribution among areas, we realize that the tendency is almost the same as the one of population influx. The gap became wider in 1960's and the bubble economy, then became narrower for the meantime, but shows expansion again in recent years. The data for 2003 indicates that the average income per capita in Tokyo at the top of the list is more than twice of the one in Okinawa at the bottom. Even in Japan, the gap between metropolitan areas and other areas is not small.

A link between national land planning and environmental policies - living in two areas

While Japan's population is obviously decreasing in the long run, only the Tokyo metropolitan area is drawing populations. It means depopulation is accelerating in suburbs and mountain areas. Will the concentration of population into urban areas continue as it has been? Or, will the trend change and will the population be dispersed to the rural areas? No one knows the ideal answer to the question of how the future of the cities will be. But, let me introduce some of the proposals that have been made.

For example, the Ministry of Land, Infrastructure and Transport is now studying, in its national land plan, the idea of having two houses both in a city and in a non-urban area. When the environmental problems simply meant pollution, the environmental aspect was just one of the points of concern in the national land "development" plan. Now, our perception has changed and the national land planning and environmental policies must be linked with each other. Some local governments seek the possibility of using the environmental industry like biomass for revitalization of the region. If these two are well linked, they will propel the national land planning.

There was a survey that asked people what an ideal residential area is like. The result clearly shows a shift in preference from midtown areas to the cities and villages in provinces. The trend is obvious especially among people above 50. It is a clear indication of their hope for moving from Tokyo to other regional areas after retirement.

Vision of the low carbon society in 2050

Another example is an effort to delineate a picture of a future society in relation to the measures against global warming. Although how CO2 emission should be reduced is a frequent topic of discussion, simple advocacy of the goal of global warming prevention is not persuasive enough. The starting point should be drawing a vision of the society. The National Institute for Environmental Studies has drawn two visions of the 70-percent reduction of greenhouse gases in its Japan Low Carbon Society Scenarios toward 2050.

Scenario A is an energetic, convenient and comfortable society where population is centralized in urban areas and individualism is regarded as important. They have advanced recycling technologies, with which they try to solve environmental issues. Scenario B means decentralization of population and attaches importance to the role of communities. The local community produces and consumes what is required as much as possible by itself and respects its social and cultural values.

The two scenarios should have both advantages and disadvantages. In Scenario A, for example, population in agricultural or mountainous areas will reduce by half; medium or small-sized cities will be less energetic; and the level of public services based on infrastructures such as medical care or water supply and sewerage systems will become lower. On the other hand, in Scenario B, as long as Japan cannot live alone in a global society, international competitiveness will be reduced and financial problem may arise on a national level. Having more latitude means a complacent situation in a sense. It may be a society where people with high competence cannot make use of it.

Mini Workshop
"Consider how the future society should be, using examples of two scenarios."

The following opinions were expressed by the students:

  • It is a good idea to choose where you live based on the life stages; for example, living in an urban area when young, moving to regional areas when married and raising children, and then coming back to a city area when old.
  • Mixture of Scenario A and B is ideal. How about establishing universities in depopulated areas, using power and ability of young people and solving problems of the community with collaboration between local governments and residents?
  • Scenario B is suitable for the coming aging society with a falling birthrate. If we make full use of the power of women and foreign workers, GDP of the Scenario A level may be attained.
  • If we promote a policy that can minimize the cost of transportation including the Shinkansen bullet trains, information and infrastructure, every part in Japan will be the suburbs of Tokyo in a sense. This will reduce disadvantage of living in regional areas and may be a new model of land planning.
  • If people live scattered in mountainous areas, the administrative services cannot reach them. It is good to have residents live in local cities to some extent. Then, how about characterizing each major city in each region as a university city, a tourist city or an industrial city?

If this trend continues, the society will be something like Scenario A. To realize Scenario B, sufficient income and quality of life must be assured even in regional areas and the community must be full of vitality.

We have confused increase in population with vitality somehow. To improve the quality of life, characteristics of the region and enjoyment of living there must be enhanced. While endeavoring to realize Scenario B, in reality, each individual person may have option to choose a life similar to A or B.

Trade-off and coexistence of environmental burden and quality of life

We have to note that improvement of quality of life (QOL) and environmental burden are in a trade-off relationship. Let us pick up some familiar cases we may come across in a downtown.

If an elevator is installed in a station, it will provide barrier-free access and ensure quality of life for certain people. But, it will consume more electricity than stairs and increase environmental burden.

Frequent train service is convenient for sure, but it will impose a certain load on the environment. Like JR Yamanote Line, if it has huge number of passengers, a load per person is comparatively small. But if the passenger number is much smaller, the number of train service must be reduced. On the other hand, if the interval is 30 minutes, it will be so inconvenient that more people will use cars instead of trains. It will impair convenience and produce another environmental burden. When we look at Tokyo and its vicinity, Tsukuba city is a good example.

Culture and quality of life in each region are important factors and they cannot be measured only by the magnitude of environmental burden. In the past, QOL was measured by physical satisfaction. For example, people wanted to buy a car and live a convenient life. Now that environmental burden has been increasing in pursuit of such desire, QOL in a mental sense tends to be and will be sought. Although mental quality does not increase the burden, CO2 will not be reduced without further action. Under the circumstances, environmental friendliness that can contribute to CO2 reduction adds value. In a real urban development, this point of view is essential.

How will be the urban area in Japan?

There is no helpful model case about this question even outside Japan. It is effective to know each individual case but mere imitation will not be meaningful, as what is ideal depends on what the standard of value is.

What can we do to make much of diversity in each region and to create a community full of vitality? Originally, each community has its own characteristics. They are not visible in our daily life but they will be apparent when we are involved in community building. This process is very important. Only a few people are involved in it today, but considering how to vitalize our own community naturally leads to the actual vitalization of the region. It is desirable that this virtuous circle will be generated in each region.

Although the title of the lecture was "concentration of population into urban areas", I dared to pay attention to a decrease in population in Japan. How the society will be in 2050 depends on what measures will be taken until around 2020 to 2030, when today's young people work in the front-line of society. I hope you will form your opinion in the process of exchanging your thought with a variety of people in a variety of position. I really hope you will contribute to the presentation of a new dimension of Japan.