Joel E. Cohen is Abby Rockefeller Mauzé Professor of ­Populations at the Rockefeller University and Columbia University and the author of How Many People Can the Earth Support?
 (April 2014)

The Case for More Babies

Titian: The Worship of Venus, 1518–1520
Jonathan Last wants Americans to have more babies. If we don’t, he warns, the proportion of young people will fall while the proportion of old people will rise to unprecedented levels. This aging of the population will bankrupt our retirement system or divert spending from other priorities or—heaven forbid—lead to an increase in taxes. It will weaken America’s capacity to project military power in the world because families with few offspring will be reluctant to sacrifice them in battle. It will diminish the proportion of innovators in the economy and lower America’s rate of economic improvement. It will undermine America’s competitive position in the world.

What Will It Take to Save the Earth?

A solar power plant with sunflowers in the foreground, Seville, Spain, 2007; detail of a photograph by Henrik Saxgren from his 2009 book Unintended Sculptures, which collects his images of man-made objects—paved roads, power lines, and wind turbines among them—that appear to have been abandoned to nature. It is published by Hatje Cantz.
The lights must never go out, The music must always play. —W.H. Auden, “September 1, 1939” Daniel Yergin’s 804-page The Quest: Energy, Security, and the Remaking of the Modern World raises large questions: Can today’s $65 trillion world economy be sure it will have the energy it needs to …

Disaster Watch

Under the ominous title Global Catastrophes and Trends: The Next Fifty Years, Vaclav Smil, a versatile geographer at the University of Manitoba, provides a broad, factual vision of the “major factors that will shape the global future [to 2050] and…their probabilities and potential impacts.” He warns the reader not to …

The Bright Side of the Plague

What was the infectious agent of the Black Death that struck Europe in 1348 and succeeding decades? The classical answer is Yersinia pestis, today’s bubonic plague. But if the disease had been bubonic plague, then outbreaks in the human population should have been preceded by extensive deaths among local rodents.

How Many People Can the Earth Support?

The question “How many people can the Earth support?” is useful, though it is seriously incomplete. It focuses attention on the present and future numbers, qualities, activities, and values of humans in their relations with one another and with the Earth. To explain why people are interested in this question, …