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Rio+20 Feature: Seven Issues, Seven Experts – Cities

Joan Clos, Executive Director of UN-Habitat.
UN Photo/P. Filgueiras
Joan Clos, Executive Director of UN-Habitat.

Rio+20 Feature: Seven Issues, Seven Experts – Cities

Cities – Executive Director of UN-Habitat, Joan Clos

World leaders, along with thousands of participants from governments, the private sector, non-governmental organizations (NGOs) and other groups will come together from 20-22 June in Rio de Janeiro, Brazil, to take part in the UN Sustainable Development Conference (Rio+20).

In our Seven Issues, Seven Experts series, UN officials tell us more about the key issues that will be discussed during the conference and how we can contribute to make our planet more sustainable.

In the fifth installment, the UN News Centre spoke with the Executive Director of UN-Habitat, Joan Clos, who tells us why rapidly growing cities can be an asset for countries if they know how to plan in advance for urbanization.

UN News Centre: What makes up a sustainable city?

Joan Clos: A sustainable city is one which contributes to sustainable development, and to do this it must have a high level of urbanization. This is what is happening in different parts of the world, and especially in sub-Saharan Africa, where in order to accelerate development there is a process of urbanization taking place. Without urbanization, it’s nearly impossible to have important development and growth in the economy.

To have a city that generates wealth, prosperity and jobs for young people, you need to have planned organization. You need an urban plan and you need to have public spaces and basic services. This is the price one needs to pay so that a city, on top of being a city, is a wealth-generating engine.


A view of passengers aboard trains connecting the suburbs of Kolkata, India. The Asia-Pacific region is urbanizing rapidly with 1.77 billion people living in urban areas. UN Photo/Kibae Park

The way a city can generate wealth is when it is a space for communication between the people and facilitates the movement of persons, goods and services. For that, you require good street grids, basic services such as sewage and drainage, illumination, lighting, etc. All of that is required in order to have sustainable city and that requires commitment from local governments.

UN News Centre: What are the most pressing issues that governments need to act on regarding sustainable cities? What could happen if we don't act on them?

Joan Clos: The first is that proper attention should be given to public spaces. In a city, at least 35 to 40 per cent of the land should be used for communication and public space. Otherwise it is very difficult to organize a transportation system that allows for proper inter-communication between the different factors and the different areas of the city.


A hillside slum area in Port-au-Prince, Hait. UN Photo/Sophia Paris

For example, in Manhattan, New York, 50 per cent of the land is allocated to mobility and public spaces. This is not the case in the developing cities. In the developing cities, we have figures of percentage of land allocated to roads and communication systems which usually do not exceed 10 per cent, and this is low because as those cities are growing very fast, then they can collapse very easily. This is a problem that requires a very high degree of attention.

UN News Centre: Can you give an example of a project that is succeeding in making a city more sustainable?

Joan Clos: Well, there are many cities that are now trying to introduce rapid bus systems, those are cities that are worried about connectivity and mobility, and are doing huge efforts to address those problems. The question is that we are now at a level of urbanization, with around 40 per cent of the population living in cities, and we know that in the coming 30 years, there is going to be a huge growth of urbanization. My advice is to plan in advance for urbanization because planning allows policymakers to direct the process, and prevent some of the big mistakes that later on become a problem for the development of the city.


Traffic congestion in Kabul, where more than 400,000 vehicles often drive on the ctiy's roads. UN Photo/Nasim Fekrat

This is what we will insist in Rio: that is it crucial to plan in advance, as we are still in the developing world in a phase of rapid urban growth. Now is the time to prepare a good plan for the next urbanization phase in the coming 10-20 years. This is the most important thing. I think we can repair the things that are not working properly, but it’s [planning] much more important due to the expected growth of urbanization. If we do this, the growth of the city is much less costly and it will perform much better.

UN News Centre: Is there a specific goal for Rio+20 regarding sustainable cities?

Joan Clos: We are proposing a series of measures in order to increase the awareness and interest of politicians and stakeholders so as to help improve understanding of urbanization issues in-depth. Urbanization issues [are] crucial for development. There’s no development without urbanization, but it’s not enough just to have people… one on top of the other, accumulated in the urban area. On top of that, you need to organize the spatial order and you need institutions. You need a lot of things, but also you need a clear layout of the city with respect to public spaces, as I have mentioned.

Facts and figures

  • Half of humanity – 3.5 billion people – live in cities today.
  • By 2030, almost 60 per cent of the world’s population will live in urban areas.
  • 95 per cent of urban expansion in the next decades will take place in developing world.
  • 828 million people live in slums today and the number keeps rising.
  • The world’s cities occupy just 2 per cent of the Earth’s land, but account for 60-80 per cent of energy consumption and 75 per cent of carbon emissions.
  • Rapid urbanization is exerting pressure on fresh water supplies, sewage, the living environment, and public health.

There is still another thing that is required and this is some minimum density – the proximity of the people. There has been a tendency in some parts of the world to increase the sprawl of the city, the scattering of the people around the land, and diminishing the density.

There are some traditional cultures, like some of the ancient cultures of Africa, where people are not used to [living] in dense settlements and even if they go to the city, they organize their dwellings in a way that resembles that of the village, but that doesn’t produce wealth if there’s no minimum density. We are talking about a net density of more than 10,000, 15,000 inhabitants per square kilometre. This is something that is very complex to attain in cultures where there is no tradition yet of urbanization. That requires change of mentality, a change of behaviour, and for people to adapt a new kind of life, and that is quite an important change which should be guided and helped in order to create a city that produces jobs and prosperity.


A slum in Rio de Janeiro, Brazil. UN Photo/Claudio Edinger

UN News Centre: What are some concrete actions that people can take to contribute to making their cities more sustainable?

Joan Clos: The most important contribution that people can make is to ask their local governments to prepare their city for the next wave of population growth, and then plan for enlargement in the existing layout of the city. Also, we are promoting a campaign, which is called “I am a city changer.” I think this is very important - to raise awareness in the general public that our cities are going to grow, and that this growth should be planned.