Science Sundays: Joel Cohen – The Human Population: Its Past and Its Prospects

Dr. Joel Cohen

The history of the human population results from interactions among demography, economics, the environment, and culture. The human population today is very heterogeneous. In 2005-2010, roughly half (48%) of the world’s people lived in the 75 countries where fertility was below replacement level, although population continued to increase in many of these countries. Roughly 1/8 of the world’s people live in regions with 4 or more children per woman per lifetime. The fractions of people living in cities and the fractions of old people also differ widely among regions. Under assumptions that are plausible but by no means certain, most demographers anticipate that, by the middle of the 21st century, the world’s population will be larger by several billion people, more slowly growing, more urban, and older. Actions taken now can strongly influence the world we will have half a century from now.

Joel E. Cohen is Professor of Populations in the School of International Relations and Public Affairs; the Department of Earth and Environmental Sciences; and the Center for Environmental Research and Conservation at Columbia University. He also is the Abby Rockefeller Mauze Professor of Populations at Rockefeller University and director of the Laboratory of Populations at Rockefeller University & Columbia University in New York.