22 Sustainable Cities

In 2011 the world's population topped seven billion people. The number of megacities with populations in excess of ten million people also continues to grow. We now live in an age in which over than half the world's population live in cities. As climate fluctuations become increasingly severe, realizing sustainable cities is becoming an issue of importance to everyone around the world. In this edition of Earthrium, we consider the future of cities from the point of view of sustainability and adaptation to climate change.

Reporting: Soichi Ueda
Photography: Tomoyo Yamazaki
Cooperation: National Institute for Environmental Studies

last update 2014.10.27


This time we've plotted on the Earthrium globe megacities (cities with populations in excess of 10 million people) from 1950 through 2025 based on data from a 2011 report by the United Nations Department of Economic and Social Affairs (UN DESA).

In 2010, the population of the worldfs megacities in the world ranked as follows.

1Tokyo (Japan)36.93 million
2Delhi (India)21.94 million
3Mexico City (Mexico)20.14 million
4New York (USA)20.1 million
5Sao Paulo (Brazil)19.65 million
6Shanghai (China)19.55 million
7Mumbai (India)19.42 million
8Beijing (China)15 million
9Dakar (Bangladesh)14.93 million
10Kolkata (India)14.28 million
11Karachi (Pakistan)13.5 million
12Buenos Aires (Argentina)13.37 million
13Los Angeles (USA)13.22 million
14Rio de Janeiro (Brazil)11.87 million
15Manila (Philippines)11.65 million
16Moscow (Russia)11.47 million
17Osaka (Japan)11.43 million
18Cairo (Egypt)11.03 million
19Istanbul (Turkey)10.95 million
20Lagos (Nigeria)10.79 million
21Paris (France)10.52 million
22Guangzhou (China)10.49 million
23Shenzen (China)10.22 million

The same report predicted that by 2015 the following 14 cities would be added to the list of megacities: Kinshasa (DR Congo), Chongqing (China), Bangalore (India), Jakarta (Indonesia), Chennai (India), Wuhan (China), Tianjin (China), Hyderabad (India), Bogota (Columbia), Lima (Peru), Chicago (USA), Bangkok (Thailand), Lahore (Pakistan), London (UK).

*UN statistics are based not on administrative divisions but on "urban agglomerations," meaning the population for Tokyo, for example, includes people living not only in Tokyo prefecture but in Yokohama and other surrounding regions as well.

Towards sustainable cities


Tokyo: the world's largest megacityi© Tomo.Yunj

According to the United Nations Population Fund (UNFPA), in 2008 half the world's population already lived in cities, and in 2050, when the world's population is expected to top nine billion people, two-thirds of us will be city-dwellers. As you will see at a glance if you look at the globe, in emerging regions such as China, India and Africa, a large number of massive cities will appear. In order to build a sustainable society in which humans and the natural environment co-exist, thinking about the sustainability of such cities is an issue that cannot be ignored. On top of this, climate fluctuations are predicted to become more severe, and for this reason it could also be said that building cities that can also deal with natural disasters is a matter of urgency.

With this in mind, we talked to Yasuaki Hijioka, Head of the Environmental Urban Systems Section within the Center for Social and Environmental Systems Research at the National Institute for Environmental Studies and Coordinating Lead Author on the Intergovernmental Panel on Climate Change (IPCC), about climate change and cities.

¨We asked an expert!

ͺ page top

We asked an expert!

National Institute for Environmental Studies
Environmental Urban Systems Section