Population experts project that in 30 years 9 billion people will reside on this planet. That’s a staggering total, especially considering the demands such a number will place on our natural resources. World population surpassed 7 billion in 2011.
Efficient food production will become critical, but, food may not be the most important issue facing people at mid-century. The World Health Organization says the rapid increase of urban populations, especially slum populations, means health issues will remain a critical threat to humans. The agency cites overcrowding, lack of safe water, and improper sanitation systems as the primary factors contributing to poor health among the urban poor. Slums often become breeding grounds for diseases like tuberculosis, dengue, pneumonia, and cholera.
As global population expands, most of the growth will be in urban areas, according to new research conducted by the Worldwatch Institute, suggesting additional population growth in slum areas and further health concerns.
Grant Potter, author of the Worldwatch Institute study, says the world’s urban population is expected to grow by 2.6 billion people between 2011 and 2050, bringing the number of urbanites to 6.3 billion. That’s especially concerning to developing countries, where 82 percent of the world’s population currently lives.
The developing world is less urbanized than the industrial world, yet developing countries are home to an estimated 1.54 billion more people. Population growth studies, however, suggest cities in the developing world will add 2.45 billion people by the year 2050, while industrial world cities will add just 170 million. The industrialized world has little room to urbanize further: it was 78 percent urban in 2011, and by 2050 it is expected to be approximately 86 percent urban. By comparison, the developing world was only 47 percent urban in 2011, a share that could reach 64 percent by 2050.
The Worldwatch Institute says within the developing world, the vast majority of this urban growth is projected to occur in Asia and Africa. Asia far outstrips Africa in total population, with 4.2 billion people in 2011 compared with Africa's 1 billion. But these regions are also the least urbanized areas on Earth: Asia's population was 45 percent urban in 2011, and Africa's was only 40 percent urban. In Latin America and the Caribbean, by contrast, 78 percent of the regions' 599 million people live in cities.
A characteristic feature of Asian urbanization is the prevalence of "megacities" that are home to more than 10 million people. In 2011, there were 23 such cities worldwide, 13 of which were Asian. By 2025, the total number of megacities is expected to reach 37----with 21 in Asia alone. Southeast Asia is the most densely settled subregion in Asia, with approximately 16,500 people per square kilometer (compared with only 4,345 people per square kilometer in Europe in 2000).