Hey Mr. Green,

Earth’s population has grown by about 700,000,000 people since your February 25, 2009, column regarding procreation, when Earth’s population was approximately 6.9 billion. Is this a reason for concern? 

—Craig in Raleigh, North Carolina

Your numbers are correct. The world’s population now exceeds 7.6 billion and continues a net growth of about 80 million a year, though not as fast as it might have been, thanks to a variety of factors that have tended to reduce birth rates.  

Global population is expected to hit 9.8 billion by 2050, according to the latest projections by the United Nations. Not everybody agrees that the increase will be this large. For example, Sanjeev Sanyal, now the principal economic adviser in the department of economic affairs for India’s Ministry of Finance, has said that global population will hit 8.7 billion by 2050. He argues that efforts to slow population will accelerate, and sees it peaking at around 9 billion before the number declines. Still, that is a mighty big number.

Complicating the whole issue is that while many countries still face a population increase, others are worried about a loss of population. That could pressure a younger and a smaller workforce to contribute more support to the fast-growing numbers of elders. Consider Japan, whose population has been dropping rapidly: The number of Japanese has plunged by almost a million since 2014, while the fertility rate is down to 1.4 births per woman. (When the sale of adult diapers eclipses the sale of infant diapers, as it did several years ago in Japan, you sense the problem.) But Japan is far from alone: Some 48 countries will experience a decline in population by 2050, according to predictions from the United Nations and other population observers, and many countries around the world already have birth rates much lower than needed to maintain existing population numbers.

Among the remedies being considered by Japan are adding more women to the workforce; further development of high technology; free education; encouragement of a higher birth rate; and promoting more immigration.