The news of the 8 billionth person joining our species last week was a joyous affair, with the UN secretary general, António Guterres, declaring it “an occasion to celebrate”. In contrast, when the global population hit 4, 5, 6 and 7 billion, in 1975, 1987, 1999 and 2011 respectively, there was widespread dismay, although that did reduce with each billion. The doubling of our numbers in 47 years did not bring about the famines and other disasters widely predicted in the 1960s.
As Poonam Muttreja, the executive director of the Population Foundation of India, explained last week, we welcomed the new child whose birth marked this event and we are no longer afraid. We have learned that most of our population growth is not due to births but to most of us living much longer, as the Swedish physician and statistician Hans Rosling so brilliantly explained. When sadly he died in 2017, aged just 68, global average life expectancy was 72.
