The world will hit its peak global population around the year 2064, according to a new modelling study, and slowly decline after that.
The peak, the researchers estimate in a study published in the Lancet medical journal, will be 9.73 billion, declining to 8.79 billion by the year 2100.
“Continued global population growth through the century is no longer the most likely trajectory for the world’s population,” lead study author Dr. Christopher Murray, director of the Institute for Health Metrics and Evaluation, said in a press release.
The authors expect population growth and decline to vary considerably by country. Japan and Italy’s populations will fall by more than 50 per cent by 2100, the study says.
According to their projections, Canada will hit a peak population of 45.2 million in 2078. Canada’s current population is just under 38 million, Statistics Canada says.
The population is expected to triple in the region of sub-Saharan Africa by the end of the next century, and North Africa and the Middle East’s population is also expected to grow.
There are “two tracks” to the story, said Rania Tfaily, an associate professor of sociology at Carleton University. In highly industrialized countries like Canada, where the fertility rate is expected to remain the same or decline, populations will decline unless there is massive immigration or another policy response.
“This has implications for the number of people of working age, the number of people available to support the elderly population,” she said. “It is often brought up that this could have implications for our ability to meet financial obligations in terms of social security or health care.”
On the other hand, in poorer countries where the population continues to expand, “this would put additional pressure in terms of space, in terms of accessibility to water, to basic infrastructure.”
The authors calculated their estimate based on factors like migration, fertility rates, deaths and other demographic information.
Their estimate is considerably lower than one produced by a United Nations agency. The authors of the Lancet paper say this is because there has been an “unprecedented” decline in fertility in sub-Saharan Africa recently, which the latest UN report hasn’t accounted for. They also say women’s educational attainment and access to contraception could have an effect.
Tfaily, who has studied women’s changing reproductive choices, said that before the Industrial Revolution, women typically had many more children – but only two might survive, meaning that population growth wasn’t that quick.
In industrialized countries, she said, falling fertility rates are linked to urbanization and increases in women’s education and employment opportunities. There’s also been a change in many people’s calculations when it comes to having a family, she said.
“Having children is becoming rather than a source of child labour as it used to be in the past, that is becoming more of a burden on women’s education and labour force participation.”
While many countries have tried to encourage women to have more children at one time or another, these programs have been largely unsuccessful, she said.
For industrialized countries, maintaining the population means encouraging immigration instead, said Ibrahim Abubakar, a professor at University College London and author of a commentary published alongside the study.
“Ultimately, if Murray and colleagues’ predictions are even half accurate, migration will become a necessity for all nations and not an option,” he wrote.
“The positive impacts of migration on health and economies are known globally. The choice that we face is whether we improve health and wealth by allowing planned population movement or if we end up with an underclass of imported labour and unstable societies.”