Megacities, Megachallenges

Of all the global demographic changes occurring in the 21st century, one of the most significant will occur in the next five years when a majority of the world's population will live in cities rather than rural areas for the first time. By 2030, the number of urban residents will double from 2.5 billion to almost 5 billion, according to a June report released by the Johns Hopkins Population Information Program at the Center for Communication Programs. The report also estimates that by 2030, 60 percent of the world's population will live in cities, with many inhabiting "megacities" (cities with more than 20 million residents) like Lagos, Bombay, Shanghai, and Mexico City.

"Often, when we think and teach about international health in developing countries, we think naturally about rural populations," says Bernard Guyer, chair of Population and Family Health Sciences at the School. Rural populations are often considered poorer, more isolated, and less healthy than their urban counterparts, Guyer explains. But the new population report shows that urban dwellers face some serious health problems: The majority of urban inhabitants lack proper sanitation, and air and water pollution kill a combined 8 to 15 million people annually.

In developing countries, the study predicts the concentration in cities will push already overburdened public institutions to the brink — leaving many people without basic services like sanitation and health care. The population shift to urban living will have profound consequences for public health and will require new approaches.

Guyer, MD, MPH, believes that the faculty members are keeping pace with the growing problems associated with urbanization. "There's been a transition in the kind of work that faculty have done, moving away from rural areas into much more urban settings," he says. Many have close ties to urban centers like Jakarta and New Delhi and are working with local officials on issues like sanitation, nutrition, and leadership development.

"These are not new problems, places like London [in the 18th and 19th centuries] had problems of solid waste disposal, overcrowding, and pollution similar to those in modern cities like Dhaka," Guyer says. In some ways, the growing urbanization will diminish differences between developed and developing countries - making research on domestic public health issues, such as controlling urban epidemics, globally relevant, he says.

Ultimately, Guyer foresees the School offering new courses on urban health issues and students increasingly focusing on urban centers for dissertation research. In order to facilitate these coming changes, he says, "We're going to have to be, as a faculty, much more informed about the urban public health situation."