Rise of the Megacity

We live in a new age of cities. Around the world, urban areas are growing faster and larger than at any previous time in human history, driven largely by rural dwellers migrating in search of economic opportunity. In 2008, for the first time ever, more than half the world’s population lived in urban areas, a share that is projected to reach 60 percent by 2030, and 70 percent by 2050.

The term “megacity” is often applied to metropolitan areas with a population of 10 million or more. In 1950, there were just two megacities in the world: New York and Tokyo. According to the National Intelligence Council, there are now 27, most of them in developing countries in Asia, Africa and Latin America.

Rapid urbanization is emerging as one of the defining trends of the 21st Century, and it is difficult to overstate the challenges it presents. To understand the scale of those challenges, consider the case of Karachi, Pakistan. Since 1950, Karachi’s population has grown nearly 2,000 percent, to more than 20 million people. (New York, by contrast, has grown a mere 30 percent during the same period.) Such frenzied growth is typical of megacities, and it is creating a host of unprecedented social and environmental problems. The United Nations estimates that as many as 50 percent of urban dwellers in the developing world live in slums, where they have little or no access to adequate shelter, clean water, sanitation, education, or health services. Traffic congestion fouls the air, and poverty is widespread.

The task is to build sustainable cities, where all inhabitants can live with dignity, security and prosperity. This will not be easy, but it is a tremendous opportunity. To seize it, cities must become massively more efficient and effective in the way they use natural resources (water, energy, land) and provide essential public services.

Most importantly, for this transformation to happen, cities will have to do things differently than they have done them in the past. Urban development models inherited from North America and Europe will not work in the megacity of the 21st century. New technologies, design philosophies, governance structures, investment vehicles, infrastructure and behaviors will be required. More efficient diffusion of learning will also be essential. And all this must occur in multiple places simultaneously, with widely varying cultures, and severe limitations on human, financial, and institutional resources. The potential, and hope, is that these constraints will foster creativity and innovation, rather than paralysis.

In future columns, I will be profiling initiatives in different megacities—exploring how they are confronting their growth, and what we can learn from them. In the effort to build a sustainable world, megacities are the laboratories. They are where social and environmental problems are most acute, but also where innovators are most abundant. Increasingly, cities are where humanity lives, so that is where humanity must learn to live sustainably. I look forward, in the months to come, to delving into specific examples from the front lines